出版者・発行元：ACS Energy Letters  

Clean energy-driven high-flux CO-to-C conversion has become increasingly urgent following the recent validation of CO<inf>2</inf>-to-CO-to-C chemical looping. This approach addresses rising net carbon emissions and the growing demand for green nanocarbons, but the CO-to-C conversion limits process capacity. Meanwhile, sustainable nanocarbon production via mainstream thermal catalytic chemical vapor deposition of hydrocarbons faces bottlenecks. CO<inf>2</inf> is released during thermal reactions, and the process is hindered by the high temperatures, gas dilution requirements, rapid catalyst deactivation, and inconsistent carbon quality. Here, we report a strategy using cost-efficient iron oxides, combining nonthermal plasma, the Boudouard reaction, and fluidized bed technology for electrified high-flux CO-to-C conversion. This process integrates high carbon yield (>228.9 g<inf>C</inf> g<inf>Fe</inf>^-1) and synthesis rate (30.2 g<inf>C</inf> g<inf>Fe</inf>^-1 h^-1), operates an electrically driven mode at a reduced temperature (577 °C), avoids catalyst deactivation (>11 h), requires no gas dilution, and produces high-quality nanocarbons (nanofibers/nanocoils), demonstrating its industrial potential for sustainable nanocarbon synthesis and CO<inf>2</inf> fixation.

DOI： 10.1021/acsenergylett.4c02660

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DOI： 10.35848/1347-4065/ad85eb

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掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Advanced Manufacturing Technology  

Direct bonding of a TP340 titanium to PEEK by hot pressing via pre-treatment of non-thermal atmospheric pressure plasma jet has been demonstrated. The plasma irradiation effect on the bonding surface on the bond strength after hot pressing was investigated. The tensile shear strength of TP340-PEEK joined by hot pressing after plasma pre-treatment was measured by comparing specimens bonded using conventional hot pressing and those bonded using adhesives. The plasma treatment to the TP340 side resulted in the formation of TiO<inf>2</inf>, which is chemically fed to oxide formation due to the irradiation of oxygen radicals generated by the plasma, resulting in a bond strength of less than 1 MPa, similar to the bond strength of the untreated specimens. The plasma irradiation effect on the PEEK side on the bond strength of TP340-PEEK bonded samples was also investigated. The bonding strength was increased by plasma irradiation to PEEK. As the plasma irradiation time was increased, the bonding strength gradually increased to 9.2 MPa, which is about 19 times higher than the bonding strength without plasma irradiation. These results suggest that oxygen radicals in the atmospheric pressure RF plasma jet produced oxygen-containing surface functional groups on the PEEK surface, which increased the strength of the TP340-PEEK direct joining.

DOI： 10.1007/s00170-024-14160-z

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その他リンク： https://link.springer.com/article/10.1007/s00170-024-14160-z/fulltext.html

担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

To realize high-capacity Ge anodes for next-generation Li⁺-ion batteries, a multilayer anode with a C(top)/Ge(middle)/C(bottom) structure was developed, where nanostructured amorphous Ge (a-Ge) and amorphous-like carbon films with a grain size of 10-20 nm were deposited sequentially by high-pressure Ar sputtering at 500 mTorr. Compared with the a-Ge anode, the C(top)/a-Ge(middle)/C(bottom) multistacking layer anode showed improved capacity degradation for repeated lithiation/delithiation reactions and achieved a high capacity of 910 mAh g⁻¹ with no capacity fading after 90 cycles at a C-rate of 0.1.

DOI： 10.35848/1882-0786/ad2785

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掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Advanced Manufacturing Technology  

The direct bonding of A5052 aluminum (Al) alloy to the engineering polymer poly(ether ether ketone) (PEEK) using an atmospheric pressure plasma-assisted process was demonstrated. The effect of plasma irradiation on the bonding surface of metal resin on the bonding strength following thermal press fitting method was investigated. Specimens bonded by plasma irradiation on the PEEK surface only showed a high tensile shear stress of 15.5 MPa. With increasing plasma irradiation time, the bond strength of the samples bonded to the PEEK surface by plasma irradiation increased. The increase in the bond strength between metals and polymers following direct bonding is caused by the addition of oxygen functional groups on the polymer. In contrast, specimens in which only the Al was exposed to the plasma showed a decrease in bond strength compared with unirradiated samples. This reduction in bond strength is attributed to the forming magnesium oxide, which forms in the early stages of participation due to plasma irradiation.

DOI： 10.1007/s00170-023-12747-6

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その他リンク： https://link.springer.com/article/10.1007/s00170-023-12747-6/fulltext.html

掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Advanced Manufacturing Technology  

Aluminum alloy A1050 to polyetheretherketone (PEEK) direct joining with hot-pressing process via pre-treatment using non-thermal atmospheric pressure plasma jet has been performed. The effect of plasma irradiation on the tensile shear strength of A1050-PEEK direct bonded specimens joined by a combination of hot-pressing process and pre-plasma treatment using non-thermal atmospheric pressure plasma jet was investigated. A1050-PEEK bonded samples with plasma-treated PEEK only showed high tensile shear stress of 13.4 MPa. This increase in tensile shear strength is attributed to the addition of oxygen functional groups on the surface of the PEEK by reactive oxygen species produced by the plasma jet.

DOI： 10.1007/s00170-023-12827-7

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その他リンク： https://link.springer.com/article/10.1007/s00170-023-12827-7/fulltext.html

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Manufacturing Processes  

This work demonstrates the direct bonding of stainless steel (SUS304) to poly(ether ether ketone) (PEEK) using non-thermal atmospheric pressure plasma-assisted joining technology in association with thermal press fitting. The tensile shear stress values of specimens bonded after plasma treatment of both the SUS304 and PEEK surfaces were higher than those of untreated samples and samples for which only one of the two surfaces was exposed to the plasma. These results indicate that the surface physical and chemical changes induced by exposure to the radio frequency plasma jet significantly increased the bonding strength.

DOI： 10.1016/j.jmapro.2023.09.049

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DOI： 10.35848/1347-4065/acfc50

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Materials Letters  

The charge/discharge capacity and cycle performance of lithium-ion batteries (LIBs) are studied in terms of the nanostructure of silicon-based anode materials and doping. The anode material is chosen to be either hydrogenated amorphous silicon (a-Si:H) or hydrogenated microcrystalline silicon (μc-Si:H), in which the doping is controlled between non-doped intrinsic i-type and phosphorous-doped n-type. The results show that a LIB test cell composed of a n-type a-Si:H anode yields a higher performance. The specific capacity during discharge is obtained initially at 2478 mAh/g, 1940 mAh/g after 10 cycles, and 1360 mAh/g after 40 cycles under a 0.2C condition.

DOI： 10.1016/j.matlet.2023.134777

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Scientific Reports  

To realize high-capacity Si anodes for next-generation Li-ion batteries, Si/Sn nanowires were fabricated in a single-step procedure using He plasma sputtering at a high pressure of 100–500 mTorr without substrate heating. The Si/Sn nanowires consisted of an amorphous Si core and a crystalline Sn shell. Si/Sn composite nanowire films formed a spider-web-like network structure, a rod-like structure, or an aggregated structure of nanowires and nanoparticles depending on the conditions used in the plasma process. Anodes prepared with Si/Sn nanowire films with the spider-web-like network structure and the aggregated structure of nanowires and nanoparticles showed a high Li-storage capacity of 1219 and 977 mAh/g, respectively, for the initial 54 cycles at a C-rate of 0.01, and a capacity of 644 and 580 mAh/g, respectively, after 135 cycles at a C-rate of 0.1. The developed plasma sputtering process enabled us to form a binder-free high-capacity Si/Sn-nanowire anode via a simple single-step procedure.

DOI： 10.1038/s41598-023-41452-3

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Thermal desorption spectroscopy using stable isotopes of ¹⁸O<inf>2</inf> and D<inf>2</inf> was employed to investigate the incorporation and behavior of oxygen-based species in a-IGZO films during plasma assisted processing. Specifically, the behavior of oxygen introduced during deposition with an Ar-¹⁸O<inf>2</inf> plasma was assessed. The data show that the oxygen amount incorporated in these films during deposition was greatly reduced by a post-deposition plasma treatment. The OD radicals introduced into a-IGZO films deposited with Ar-¹⁶O<inf>2</inf> during a post-treatment with an Ar + D<inf>2</inf> + O<inf>2</inf> mixture was also examined. The results indicate that −OD groups in the films were strongly bonded to the metal atoms.

DOI： 10.35848/1347-4065/acdb7e

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Plasma-sputtered amorphous films for all-solid-state Li⁺-ion batteries are investigated. In LiPON electrolyte films, the amount of N incorporated into LiPO films is controlled by the sputtering discharge gas. Ionic conductivity increases with increasing N<inf>2</inf> gas proportion in Ar/N<inf>2</inf> discharge, reaching a maximum of 2.7 × 10⁻⁶ S cm⁻¹ at Li<inf>2.39</inf>PO<inf>3.71</inf>N<inf>0.13</inf>. In amorphous LiAlGePO electrolyte films, the amounts of Al and Ge incorporated into LiPO films are controlled in a combinatorial approach using two-source co-sputtering. The P/Ge ratio varies over a wide range from 23.3 to 1.61 at the radial substrate positions, and the highest ionic conductivity of 4.32 × 10⁻⁵ S cm⁻¹ is achieved at Li<inf>4.80</inf>Al<inf>0.80</inf>Ge<inf>1.16</inf>P<inf>3</inf>O<inf>13.1</inf>. We evaluate all-solid-state Li⁺-ion batteries fabricated using the developed amorphous LiPON electrolyte and GeSn anode films, where GeSn films with about 50 nm nanograins are fabricated by high-gas-pressure sputtering at 500 mTorr. A maximum capacity of 2.86 μAh cm⁻² is attained for all-solid state Li⁺-ion battery.

DOI： 10.35848/1347-4065/acd55d

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Vacuum  

This work assessed the effects of residual oxygen remaining on the surfaces of a plasma-assisted reactive sputtering chamber during the deposition of a-InGaZnO<inf>x</inf> (a-IGZO) thin films, based on employing a stable oxygen isotope together with thermal desorption spectroscopy. The absorption of oxygen by such films may affect the deposition process, especially in the case that residual oxygen is left on the chamber walls by a preceding deposition. Trials using ¹⁸O<inf>2</inf> as a stable isotope of oxygen showed no evidence of the contamination of a-IGZO thin films by oxygen desorbed from the chamber walls. These results indicate that residual oxygen and other substances on the chamber walls can be expected to have little effect on the films when using this deposition technique.

DOI： 10.1016/j.vacuum.2023.112227

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The homogeneous formation of high-mobility oxide semiconductor thin films over large areas at low temperatures was accomplished by optimizing both the film formation process and the low-temperature post-processing via plasma annealing. Increasing the substrate-to-target distance (D <inf>ST</inf>) and the applied target voltage was found to produce more uniform deposition. The results of the field-effect mobility distributions of IGZO TFTs processed using plasma annealing were founded that plasma annealing generated essentially uniform distributions with μ <inf>FE</inf> values in the range of 32-35 cm² V⁻¹ s⁻¹

DOI： 10.35848/1347-4065/acbd56

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その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/acbd56/pdf

出版者・発行元：Journal of Manufacturing Processes  

This work demonstrated the joining of SUS304 stainless steel to polycarbonate (PC) using an atmospheric pressure radio frequency (RF) plasma jet in conjunction with thermal press fitting. The tensile shear stress values of samples bonded after plasma treatment of both the SUS304 and PC were found to be higher than those of specimens in which only one or neither surface was exposed to the plasma. These results confirm that an atmospheric pressure RF plasma jet can be applied to the joining of different materials.

DOI： 10.1016/j.jmapro.2022.01.041

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Nature Portfolio  

We fabricated nanostructured Ge and GeSn films using He radio-frequency magnetron plasma sputtering deposition. Monodisperse amorphous Ge and GeSn nanoparticles of 30–40 nm size were arranged without aggregation by off-axis sputtering deposition in the high He-gas-pressure range of 0.1 Torr. The Ge film porosity was over 30%. We tested the charge/discharge cycle performance of Li-ion batteries with nanostructured Ge and GeSn anodes. The Ge anode with a dispersed arrangement of nanoparticles showed a Li-storage capacity of 565 mAh/g after the 60th cycle. The capacity retention was markedly improved by the addition of 3 at% Sn in Ge anode. The GeSn anode (3 at% Sn) achieved a higher capacity of 1128 mAh/g after 60 cycles with 92% capacity retention. Precise control of the nano-morphology and electrical characteristics by a single step procedure using low temperature plasma is effective for stable cycling of high-capacity Ge anodes.

DOI： 10.1038/s41598-022-05579-z

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：最終著者   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We present a study on morphological control of nanostructured Ge films by the Ar gas pressure in plasma sputtering deposition. In the low Ar-gas-pressure range, aggregated islands of amorphous grains are formed on the film surface, while in the high-pressure range of 500 mTorr monodisperse nano-grains of about 30 nm in size are orderly arranged without aggregation. The film porosity shows a high value of over 10%. We tested the charge/discharge cycle performance of Li-ion batteries with nanostructured Ge films as anodes. The battery cell with an ordered arrangement structure maintained a high capacity of 434 mAh g-1 after 40 charge/discharge cycles, while that with an aggregated structure exhibited a rapid degradation of capacity to 5.08-183 mAh g-1. An ordered arrangement of Ge nano-grains with a high porosity, which is realized in a simple one-step procedure using high Ar-gas-pressure plasma sputtering, is effective for the stable cycling of high-capacity metal anodes.

DOI： 10.35848/1347-4065/ac2b7b

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Open Journal of Nanotechnology  

We fabricated nanocrystalline Ge films using radio-frequency (RF) magnetron plasma sputtering deposition under a high Ar-gas pressure. The Ge nanograins changed from amorphous to crystalline when the distance between the Ge sputtering target and the substrate was decreased to 5 mm and the RF input power was 11.8 W/cm2 (60 W), where the deposition rate was as high as 660 nm/min. In addition, the size of the nanocrystalline grains increased from 100 to 307 nm when the RF input power for plasma production was increased from 11.8 W/cm2 (60 W) to 17.7 W/cm2 (90 W). In the developed narrow-gap plasma process at sub-Torr pressures, nanocrystalline Ge films were successfully fabricated on Cu substrates at low temperatures, without the substrate being heated. However, when annealing was conducted under an N2 atmosphere, which is the conventional method to induce solid-phase crystallization, the amorphous Ge layer on a Cu substrate changed to a Cu3Ge crystal layer through interdiffusion of Ge and Cu atoms at 400-500 °C.

DOI： 10.1109/OJNANO.2022.3221462

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Open Journal of Nanotechnology  

Plasma nanotechnology is widely used for nanoscale etching, dopant implantation and thin-film deposition for state-of-the-art semiconductor devices. Such a plasma nanotechnology has another interesting aspect of synthesizing nanoparticles, in a controlled manner of atomic composition, structure and those size. Here, we present the polymerization and growth of silicon nanoparticles from a molecular level to 10 nm-particles in hydrogen diluted silane plasmas. The polymerization and growth are experimentally studied using various plasma diagnostic tools. The results indicate that nanoparticles are rapidly formed via gas-phase reactions in a low-density plasma comprising high-energy electrons. The growth kinetics and the modification of plasma properties are discussed in terms of gas-phase reactions, charging and coagulation of nanoparticles.

DOI： 10.1109/OJNANO.2022.3209995

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出版者・発行元：Japanese Journal of Applied Physics  

Understanding the mechanisms behind plasma-induced liquid flow is important for the transport of reactive species in liquid. In this study, we studied the effects of the surrounding gas compositions of a plasma-jet on the plasma-induced downward liquid flow using particle image velocimetry. Nitrogen (N<inf>2</inf>) and oxygen (O<inf>2</inf>) mixtures in different mixing ratios were supplied as surrounding gas around a helium (He) plasma jet at a constant flow rate. The results clearly indicated that O<inf>2</inf> in the surrounding gas plays a key role in enhancing the downward flow. Increasing the O<inf>2</inf> concentration increased the downward flow in the depth direction. An emission spectroscopy analysis suggested that reactive species related to excited atomic O were considered to be important for inducing downward flows. The relationship between the downward flows and oxidation reactions on a liquid target were discussed to determine the reasons responsible for the driving forces.

DOI： 10.35848/1347-4065/ab71dc

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担当区分：筆頭著者  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Scientific Reports  

In Figure 5 there is a missing axis label. The y-axis of the bottom graph should be labelled “Intensity (arb. units)” The correct Figure 5 appears below as Figure 1. Additionally, this Article contains errors in Reference 44 which is incorrectly given as: Ito, T., Uchida, G., Nakajima, A., Takenaka, K. & Setsuhara, Y. Selective production of reactive oxygen and nitrogen species in the plasma-treated water by using a nonthermal high-frequency plasma jet. Jpn. J. Appl. Phys. 56, 01AC06 (2016) The correct reference is listed below as ref. 1:.

DOI： 10.1038/s41598-019-54737-3

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出版者・発行元：Thin Solid Films  

Functional thin films on organic materials are important in flexible electronics including next-generation flexible displays and photovoltaic cells. Herein, we describe the formation of SiN<inf>x</inf> films by plasma-assisted reactive sputtering deposition at low temperature, and detail the properties of the formed films. The effect of plasma assistance on the deposition rate and the properties of the SiN<inf>x</inf> films deposited by this system are reported as functions of relative N<inf>2</inf> partial pressure. Plasma assistance led to a deposition rate as high as 1.63 nm/s. The thin film formed at a relative nitrogen partial pressure of 21.4% exhibited a density of 2.73 g/cm³ and was more than 95% transparent over the entire visible region of the spectrum. The properties of SiN<inf>x</inf> films formed by plasma-assisted reactive sputtering deposition demonstrate the feasibility of forming SiN<inf>x</inf> films that are suitable for passivation applications in devices such as organic light-emitting diodes (OLEDs) and solar cells.

DOI： 10.1016/j.tsf.2019.06.049

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出版者・発行元：Japanese Journal of Applied Physics  

This work demonstrated the low-temperature fabrication of high-mobility a-InGaZnOx (a-IGZO) films using plasma-enhanced reactive processing. The effect of the post-processing temperature on the performance of IGZO thin-film transistors (TFTs) using these a-IGZO films as a channel layer was also investigated. IGZO TFTs incorporating a-IGZO films plasma-treated at temperatures as low as 200 °C exhibited the expected TFT transfer characteristics, with field effect mobility values as high as 40 cm² V^-1 s^-1. The fabrication of IGZO TFTs that exhibited homogeneous characteristics over large substrate areas was attempted, by assessing the effects of the plasma treatment on a-IGZO films deposited at various oxygen flow rate ratios. The electrical properties of IGZO TFTs using plasma-treated films were found to be dramatically improved, irrespective of the film deposition conditions prior to the plasma treatment. These results confirm the feasibility of producing IGZO TFTs with uniform characteristics over large substrates areas.

DOI： 10.7567/1347-4065/ab219c

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Scientific Reports  

We present evidence for the decomposition and oxidation of amino acids in aqueous solution following irradiation with a nonequilibrium plasma jet. Of 15 amino acids tested in cell culture medium, plasma irradiation induced a marked chemical change in methionine and tryptophan due to the effective production of reactive oxygen species by plasma-water interaction. We also report that plasma-treated methionine and tryptophan aqueous solutions can kill cancer cells, greatly decreasing the viability of human endometrial carcinoma (HEC-1) cancer cells due to the presence of decomposition or oxidation products generated from the amino acid. Plasma-treated methionine and tryptophan aqueous solutions also induced an anti-cancer effect on cancer-initiating cells.

DOI： 10.1038/s41598-019-42959-4

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担当区分：筆頭著者   記述言語：日本語  

出版者・発行元：Japanese Journal of Applied Physics  

Effects of post-deposition plasma treatments on the stability of amorphous InGaZnO<inf>x</inf> thin-film transistors (TFTs) prepared with plasma-assisted reactive magnetron sputtering were investigated. The temporal evolution in the electrical characteristics of as-deposited IGZO TFT and post plasma treated IGZO TFT that passed over 400 d after fabrication and were kept under 40% humidity at room temperature were measured, resulting in which no change in the electrical characteristics of post plasma treated IGZO TFT with mobility of 40 cm² V^-1 s^-1 were observed. Positive-current-bias instability in post plasma treated IGZO TFTs was examined together with as-deposited IGZO TFTs. The results indicated that the stabilities of electrical characteristics caused by the positive bias stress is primarily attributed to defects in the bulk a-IGZO region for as-deposited IGZO TFTs. The stabilities of electrical characteristics in post plasma treated IGZO TFTs were considerably improved compared to that of as-deposited IGZO TFTs. From these results, it was shown that the post plasma treatment is considered to be effective for improving the stability of IGZO TFTs as well as conventional thermal annealing.

DOI： 10.7567/1347-4065/aaec18

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出版者・発行元：Journal of Alloys and Compounds  

The effects of sputtered atom flux on the electrical properties of a-IGZO films before and after thermal annealing were examined by varying the fluxes of sputtered atoms at the substrate holder. The electrical proprieties of IGZO TFTs fabricated from a-IGZO films were found to vary widely depending on the sputtered atom flux. Specifically, the electrical properties of a-IGZO films after thermal annealing improved considerably with increasing sputtered atom flux, such that a field effect mobility as high as 23.6 cm²V⁻¹s⁻¹ was achieved following annealing. These results suggest that the electrical characteristics of IGZO TFTs after annealing are affected by the film structure, including the density and quality of the as-deposited a-IGZO films.

DOI： 10.1016/j.jallcom.2018.09.143

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

出版者・発行元：Japanese Journal of Applied Physics  

We describe the effects of the plasma-activation of a medium on the killing of cancer cells, in which the plasma-activated medium is produced by the irradiation of the cell culture medium using a low-frequency (LF) or very-high-frequency (VHF) plasma jet. The plasma-activated medium produced by the direct contact of the LF plasma jet with the liquid surface induces much lower cancer cell viability, and large amounts of oxidation products, such as gluconic acid and methionine sulfoxide, can be detected in the plasma-activated medium. Our experiments show that the process of using plasma created by the direct contact of a LF plasma jet leads to a plasma-activated medium with stronger cancer-cell killing ability compared with a no-contact process. Also, the oxidation products, such as methionine sulfoxide in the plasma-activated medium become useful proxies for lethality.

DOI： 10.7567/JJAP.57.096201

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出版者・発行元：Review of Scientific Instruments  

In this study, an inductively coupled plasma (ICP)-enhanced reactive sputter deposition system with a rectangular target was developed as a linear plasma source for roll-to-roll deposition processes. The longitudinal distribution of the film thickness indicated the feasibility of uniformity control via the control of the power deposition profile of the assisted ICPs. The characteristics of Si films were investigated in terms of the film thickness uniformity and film crystallinity. The results of Raman and X-ray diffraction measurements indicated the crystallization of the Si film with a crystallinity as high as 73%-78% in all the samples of the longitudinal position.

DOI： 10.1063/1.5037408

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Letters  

This work demonstrated the low-temperature control of the oxidation of Amorphous InGaZnO<inf>x</inf> (a-IGZO) films using inductively coupled plasma as a means of precisely tuning the properties of thin film transistors (TFTs) and as an alternative to post-deposition annealing at high temperatures. The effects of the plasma treatment of the as-deposited a-IGZO films were investigated by assessing the electrical properties of TFTs incorporating these films. A TFT fabricated using an a-IGZO film exposed to an Ar-H<inf>2</inf>-O<inf>2</inf> plasma at substrate temperatures as low as 300 °C exhibited the best performance, with a field effect mobility as high as 42.2 cm² V^-1 s^-1, a subthreshold gate voltage swing of 1.2 V decade^-1, and a threshold voltage of 2.8 V. The improved transfer characteristics of TFTs fabricated with a-IGZO thin films treated using an Ar-H<inf>2</inf>-O<inf>2</inf> plasma are attributed to the termination of oxygen vacancies around Ga and Zn atoms by OH radicals in the gas phase.

DOI： 10.1063/1.5011268

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The low-temperature formation of c-axis-oriented aluminum nitride thin films was demonstrated by plasma-assisted reactive pulsed-DC magnetron sputtering. The effects of the duty cycle at the pulsed-DC voltage applied to the Al target on the properties of AlN films formed via inductively coupled plasma (ICP)-enhanced pulsed-DC magnetron sputtering deposition were investigated. With decreasing duty cycle at the target voltage, the peak intensity of AlN(0002) increased linearly. The surface roughness of AlN films decreased since there was an increase in film density owing to the impact of energetic ions on the films together with the enhancement of nitriding associated with the relative increase in N radical flux. The improvement of both the crystallinity and surface morphology of AlN films at low temperatures is considered to be caused by the difference between the relative flux values of ions and sputtered atoms.

DOI： 10.7567/JJAP.57.01AD06

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出版者・発行元：Japanese Journal of Applied Physics  

We present the control of H<inf>2</inf>O<inf>2</inf> and NO<inf>2</inf> ^- productions in deionized water by using a high-frequency plasma jet driven by a 60 MHz voltage. In the gas phase, the high-frequency plasma jet has a high O (³P) atom density of 8 × 10¹⁴ cm^-3, which is two orders of magnitude higher than that of the low-frequency plasma jet driven by a 5 kHz voltage. Concerning the production of reactive oxygen and nitrogen species in the liquid phase, with the direct contact of the plasma jet to the liquid surface, the H<inf>2</inf>O<inf>2</inf> concentration is higher than the NO<inf>2</inf> ^- concentration. On the other hand, without the observable contact of the high-frequency plasm jet with high plasma density to the liquid surface, the NO<inf>2</inf> ^- concentration increases with the flow rate of N<inf>2</inf>(20%)O<inf>2</inf>(80%) gas added to the Ar discharge gas and becomes more dominant compared with H<inf>2</inf>O<inf>2</inf> in the plasma-treated water. H<inf>2</inf>O<inf>2</inf> and NO<inf>2</inf> ^- could be selectively produced in the plasma-treated water by using a nonthermal high-frequency plasma jet, which is a promising tool for biomedical applications.

DOI： 10.7567/JJAP.57.0102B4

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

High-frequency plasma jets driven by voltages in the frequency range of 6-60 MHz are developed. A long plasma jet, 40 mm in length, is successfully produced by using a pair of ring electrodes outside a quartz tube. The electrode pair consists of a wide power electrode and a narrow ground electrode that is positioned at the head of the tube. The ratio of the length of the ground electrode to the length of the power electrode must be small in order to produce long plasma jets. The high-frequency plasma jet is operated in a non-thermal-equilibrium state at a gas temperature of around 60 °C. Operation at the very-high-frequency of 60 MHz leads to a lower discharge voltage and lower electron energy compared to lower frequencies of 6 and 13.56 MHz. The ability of the very-high-frequency (60 MHz) plasma jet to produce reactive oxygen and nitrogen species in water is also investigated. High H<inf>2</inf>O<inf>2</inf> and NO<inf>3</inf>^- concentrations of more than 1 mmol/l are realized by irradiating 3 ml of deionized water with the plasma for a short period of 2 min.

DOI： 10.1063/1.4993715

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

DOI： 10.7567/JJAP.56.01A001

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We present the development of a low-frequency nonthermal plasma-jet system, where the surrounding-gas condition of the plasma jet is precisely controlled in open air. By restricting the mixing of the ambient air into the plasma jet, the plasma jet can be selectively changed from a N<inf>2</inf> main discharge to an O<inf>2</inf> main discharge even in open air. In the plasma-jet system with the controlled surrounding gas, the production of reactive oxygen and nitrogen species is successfully controlled in deionized water: the concentration ratio of NO<inf>2</inf>^- to H<inf>2</inf>O<inf>2</inf> is tuned from 0 to 0.18, and a high NO<inf>2</inf>^- concentration ratio is obtained at a N<inf>2</inf> gas ratio of 0.80 relative to the total N<inf>2</inf>/O<inf>2</inf> gas mixture in the main discharge gas. We also find that the NO<inf>2</inf>^- concentration is much higher in the plasma-activated medium than in the plasma-activated deionized water, which is mainly explained by the contribution of amino acids to NO<inf>2</inf>^- generation in the medium.

DOI： 10.7567/JJAP.56.01AC06

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Web of Science

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

The effects of working pressure on the physical properties of amorphous InGaZnO<inf>x</inf> (a-IGZO) films fabricated using inductively coupled plasma-enhanced reactive sputtering deposition were studied, while also assessing the plasma employed during film deposition. With decreasing working pressure, the ion saturation current corresponding to the plasma density increased along with the film deposition rate, because of the greater number of ions incident on the IGZO target. The physical properties of the resulting a-IGZO films were examined to determine the effect of ion energy while varying the working pressure. With decreasing working pressure, the film densities estimated from X-ray reflection data were found to increase. In addition, the concentrations of excess oxygen and hydrogen species incorporated into the a-IGZO films, which can potentially lead to structural and electrical instability, decreased. These results indicate the feasibility of enhancing the electrical properties of a-IGZO films.

DOI： 10.1109/TPS.2016.2593458

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

We present the effects of the application of a nonthermal plasma jet to a liquid surface on H<inf>2</inf>O<inf>2</inf> and NO<inf>2</inf> ^- generation in the liquid. Two distinct plasma irradiation conditions, with plasma contact and with no observable plasma contact with the liquid surface, were precisely compared. When the plasma was made to touch the liquid surface, the H<inf>2</inf>O<inf>2</inf> concentration of the plasma-treated water was much higher than the NO<inf>2</inf> ^- concentration. In contrast, when no observable contact of the plasma with the liquid surface occurred, the ratio of the NO<inf>2</inf> ^- to H<inf>2</inf>O<inf>2</inf> concentration became over 1 and NO<inf>2</inf> ^- became more dominant than H<inf>2</inf>O<inf>2</inf> in the plasma-treated water. Our experiments clearly show that reactive oxygen and nitrogen species can be selectively produced in liquid using appropriate plasma-irradiation conditions of the liquid surface. The ratio of NO<inf>2</inf> ^- to H<inf>2</inf>O<inf>2</inf> was controlled within a wide range of 0.02-1.2 simply by changing the plasma-irradiation distance from the liquid surface.

DOI： 10.1063/1.4968568

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J-GLOBAL

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

The two-dimensional concentration distribution of reactive oxygen species (ROSs) transported through an agarose-film tissue phantom by atmospheric-pressure plasma-jet irradiation is visualized using a KI-starch gel reagent. Oxygen addition to helium enhances ROS transportation through the film. A radial ROS distribution pattern at the plasma-irradiated film surface changes into a doughnut-shaped pattern after passing through the film. The ROS transportation speed is 0.14-0.2mm/min. We suggest that there are two types of ROS transportation pathways in the plasma-irradiated film: linear and circular. The majority of ROSs are transported through the circular pathway. ROS concentration distributions changed markedly with irradiation distance. Diffusive ROS transportation due to a concentration gradient is negligible in plasma-irradiated films.

DOI： 10.7567/APEX.9.076202

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

The impact of irradiation distances on plasma jet-induced specific effects on the supply of reactive oxygen species (ROS) to the bottom of a Petri dish filled with liquid was investigated using a KI-starch gel reagent that can be employed as a ROS indicator even in water. O<inf>3</inf> exposure experiments without plasma irradiation were also performed to elucidate the specific effects of the plasma jet. Relative concentrations of ROS transported to the bottom were evaluated using absorbance measurements. The results indicated that ROS supply to the bottom is markedly enhanced by the plasma jet irradiation at shorter irradiation distances, whereas similar results could not be obtained for the O<inf>3</inf> exposure. In these cases, the liquid mixing in the depth direction was also enhanced by the plasma jet irradiation only, and the supply of reactive atomic oxygen to the liquid surface was markedly increased as well.

DOI： 10.1063/1.4948430

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記述言語：英語   出版者・発行元：Science of Advanced Materials  

Si is currently the most widely used material in the photovoltaics. Since the first development of Si photovoltaics, various types of Si solar cells, such as single-crystal and multicrystalline, amorphous and thin film, have been developed and commercialized. The present work focused on Si quantum dots as another route to Si photovoltaics. To apply Si quantum dots to photovoltaic devices, the quantum characteristics of Si nanoparticles should be verified, and so 4 nm crystalline Si nano-particles were fabricated by multi-hollow discharge plasma chemical vapor deposition. The size and distribution of these particles were determined by transmission electron microscopy and compared against theoretically calculated values. These particles were applied to the fabrication of a Schottky cell and the quantum efficiency of the Si quantum dot layer was measured as a function of the incident photon energy. The quantum efficiency was found to exceed 100% and so multiple exciton generation from the Si quantum dots was clearly realized.

DOI： 10.1166/sam.2016.2520

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We present here the analysis of the discharge characteristics of a He dielectric-barrier-discharge (DBD) plasma jet operated in the voltage duty ratio of 20 to 80% under the condition of driving voltage frequency 5 kHz. Discharge strength is sensitive to the voltage pulse width, and the pulse width of 70 μs, which corresponds to the duty ratio of 35%, leads to high O optical emission intensity. We also performed time-resolved optical emission measurements in a transient pulse discharge driven by various voltage duty ratios. Two distinct pulse discharges are observed in the rising and falling periods of the positive rectangular voltage, and the first and second discharges have a peak intensity of optical emission at different duty ratio. The observations indicate that an adequate voltage pulse width could ignite a strong discharge both in the rising and falling period of applied voltage, which could produce a large amount of reactive excited O atoms.

DOI： 10.7567/JJAP.55.01AH03

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The process controllability of inductively coupled plasma-enhanced reactive sputter deposition for the fabrication of amorphous InGaZnO<inf>x</inf> (a-IGZO) channel thin-film transistors (TFTs) was investigated. a-IGZO film deposition with the addition of H2 gas was performed using a plasmaassisted reactive sputtering system to control the oxidation process during a-IGZO film formation by balancing the oxidation and reduction reactions. Optical emission spectroscopy measurements indicate the possibility for the oxidation reaction to be inhibited by a decrease in the density of oxygen atoms and the reduction effect of hydrogen during a-IGZO film deposition due to the addition of H2 gas. The characteristics of TFTs fabricated using a-IGZO films deposited with a plasma-enhanced magnetron sputtering deposition system were investigated. The results indicate the possibility of expanding the process window by controlling the balance between oxidation and reduction with the addition of H<inf>2</inf> gas. TFTs with a-IGZO films that were deposited with the addition of H<inf>2</inf> gas exhibited good performance with a field-effect mobility (μ<inf>FE</inf>) of 15.3cm²V^-1 s^-1 and a subthreshold gate voltage swing (S) of 0.48Vdecade^-1.

DOI： 10.7567/JJAP.55.01AA18

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

DOI： 10.11316/jpsgaiyo.71.1.0_868

Open Access

CiNii Research

記述言語：英語  

Web of Science

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

We present here an analysis of the discharge characteristics near the liquid surface in the plasma jet operated at a He gas flow rate of 1.5-10 slm. The plasma diameter on the liquid surface increases with an increase in He gas flow rate, which results in an increase in the total amount of charge particles transferred from the plasma to the liquid. We also analyzed the gas flow patterns using a Schlieren gas flow imaging system. The diameter of the laminar flow and the gas flow distance along the liquid surface increase with an increase in He gas flow rate, which well explains the increase in the plasma diameter on the liquid surface. Our experiments clearly demonstrate that high gas flow rate realizes the large reaction area between the water molecule and the plasma in the plasma jet system.

DOI： 10.1109/TPS.2015.2488619

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

We present here the analysis of the dynamic discharge characteristics of the plasma jet, where we set the metal plate in the downstream region and measure its voltage and current induced by the plasma-jet contact. The voltage of the metal plate is as high as 1.9 kV at a distance of 15 mm from the plasma source under the high discharge voltage condition of 9 kV. The metal-plate voltage measured at a distance of 40 mm from the plasma source decreases markedly to 0.5 kV, which is still high enough for causing chemical reactions induced by accelerated ions in the potential. The metal-plate voltage also changes in the wide range of 0.3-1.9 kV with various discharge-voltage conditions, where the metal plate is set to a distance of 20 mm from the plasma source. Our experiments demonstrate that the voltage and current measurements using the metal plate could be used as one of the effective protocols to evaluate the plasma-jet irradiation condition in the plasma-jet process.

DOI： 10.1109/TPS.2015.2482998

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Multiple exciton generation (MEG) in QDs is expected to enhance significantly the energy conversion efficiency of solar cells. Although there are several reports on MEG characteristics from various QD materials such as PbS, CdSe, CdS ZnS, and Ag2S, such materials have disadvantages of their toxicity and limited resources. Here we have developed quantum-dots (QDs) solar cells using Ge nanoparticles fabricated by rf sputtering method under high pressure. We fabricated Ge nanoparticles by rf sputtering at a pressure of 1.5 Torr. Since the mean free path of Ge atoms is an order of micrometer, and Ge nanoparticles are formed in gas phase. We fabricated Ge nanoparticles using Ar and N2 to terminate surface defects by N. Ge and Ar emission intensities decrease significantly with increasing N2 partial pressure. The electron density was measured with a plasma absorption probe. The electron density decreases with increasing N2 partial pressure.

We are developing Au-induced crystalline Ge film formation using sputtering deposition. For the method, very thin Au films were deposited on SiO2 substrates and then Ge atoms were irradiated to the Au films by sputtering. We found two kinds of Ge film growth: one is Ge film formation on Au films, and the other is Ge film formed between Au films and SiO2. The latter film formation, however, takes place in a narrow temperature range around 140°C. Here we report two kinds of substrate temperature dependence of Ge film formation: one is annealing temperature of Au films, and the other is the substrate temperature dependence during Ge sputtering. 30nm-thick Au films were deposited quartz glass as a catalyst at room temperature by sputtering. Then the Au films were annealed in a temperature range from room temperature to 190 °C in a vacuum. Au grain grows and crystal orientation shows better alignment as the annealing temperature rises. We found that the smaller grain size with random orientation is better for Ge film formed between Au films and SiO2.

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

We present here analysis of oxidation reaction in liquid by a plasma-jet irradiation under various gas flow patterns such as laminar and turbulence flows. To estimate the total amount of oxidation reaction induced by reactive oxygen species (ROS) in liquid, we employ a KI-starch solution system, where the absorbance of the KI-starch solution near 600nm behaves linear to the total amount of oxidation reaction in liquid. The laminar flow with higher gas velocity induces an increase in the ROS distribution area on the liquid surface, which results in a large amount of oxidation reaction in liquid. However, a much faster gas flow conversely results in a reduction in the total amount of oxidation reaction in liquid under the following two conditions: first condition is that the turbulence flow is triggered in a gas flow channel at a high Reynolds number of gas flow, which leads to a marked change of the spatial distribution of the ROS concentration in gas phase. Second condition is that the dimpled liquid surface is formed by strong gas flow, which prevents the ROS from being transported in radial direction along the liquid surface.

DOI： 10.1063/1.4927217

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

A plasma-enhanced sputter deposition system has been developed via enhancement of target sputter discharge with inductively coupled RF plasma (ICP) driven by multiple inner-type low-inductance antennas (LIAs). The advantage of fine control of reactivity during the deposition is of great significance for the deposition of a transparent amorphous oxide semiconductor films, amorphous InGaZnOx (a-IGZO), whose electrical properties are significantly sensitive to the reactivity of the films with oxidation species during the film deposition. The characteristics of thin-film transistors (TFTs) fabricated with an a-IGZO film using the plasma-enhanced magnetron sputter deposition system have been investigated. The a-IGZO channel TFTs fabricated using the plasma-enhanced reactive sputtering system at a substrate temperature as low as or lower than 150 °C exhibited a good performance of μ<inf>FE</inf> = 18.5cm²V^-1 s^-1.

DOI： 10.7567/JJAP.54.06GC02

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

We present here an analysis of the discharge characteristics of a He plasma jet operating under three different types of applied voltage waveform: (a) a μs-pulse voltage waveform with a slow voltage rise time, (b) ns-pulse, and (c) rectangular voltage waveforms with fast voltage rise time. Optical emission measurements show that the application of a voltage with a fast voltage rise time induces rapid discharge growth and, consequently, produces an abundance of energetic electrons, which in turn leads to high optical emission from the O atoms. We also estimate the optical emission efficiency of the O atom (η<inf>o</inf>), which corresponds roughly to the production efficiency of the reactive O species. η<inf>o</inf> increases with increasing applied voltage, and the highest value of η<inf>o</inf> is obtained in the shortest pulse discharge, which was ignited by a ns-pulse voltage waveform with a fast voltage rise time and short pulse width.

DOI： 10.1063/1.4918546

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Nanoscience and Nanotechnology  

We present He atmospheric-pressure gas-breakdown phenomena with radio frequency (RF) voltages in the frequency region from a few tens MHz to 100 MHz. The gas-breakdown voltage for RF and very high frequency (VHF) discharges is considerably lower than that for the DC discharge, and the gas-breakdown voltage is effectively reduced to be as low as 160 V in VHF region. The discharge characteristics drastically change with increasing discharge-voltage frequency, and strong emisson is highly loclized in front of the power- and ground-electrode in the VHF discharges. The lowering gas-brakdown voltage and the localized emission-profile are well explained by the effect of the charged-particle confinement in a micro dishcarge-space.

DOI： 10.1166/jnn.2015.10233

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Nanoscience and Nanotechnology  

Molecular-structure variation of organic materials irradiated with atmospheric pressure He plasma jet have been investigated. Optical emission spectrum in the atmospheric-pressure He plasma jet has been measured. The spectrum shows considerable emissions of He lines, and the emission of O and N radicals attributed to air. Variation in molecular structure of Polyethylene terephthalate (PET) film surface irradiated with the atmospheric-pressure He plasma jet has been observed via X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). These results via XPS and FT-IR indicate that the PET surface irradiated with the atmospheric-pressure He plasma jet was oxidized by chemical and/or physical effect due to irradiation of active species.

DOI： 10.1166/jnn.2015.10229

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Nanoscience and Nanotechnology  

We present here experiments on helium atmospheric dielectric-barrier discharge jet in open air. A long stable plasma plume is realized at high applied voltage and high gas flow rate. Optical emission measurements show that the plasma plume consists of two part: a plume head with high energy electrons and a tail part with low energy electrons. The plasma plume propagates away from the quartz-tube outlet with about 30-80 km/sec along the helium gas flow channel. The propagation velocity of plasma plume is in the time scale of electron drift velocity, and the electric field plays an important role as a driving force of the plasma plume propagation.

DOI： 10.1166/jnn.2015.10232

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PubMed

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

We present here the analysis of the characteristics of a dielectric-barrier-discharge (DBD) plasma jet in open air using the optical emission spectroscopy (OES). The OES on oxygen emission is useful to estimate the presence of reactive excited O atoms. The O emission intensity is much higher near the quartz-tube outlet and abruptly decreases with distance from the quartz tube. Our experiments also show that the DBD plasma jet is quite sensitive to He gas flow rate (R<inf>He-gas flow</inf>): increasing R<inf>He-gas flow</inf> induces weak pulse discharge, resulting in decreasing O emission intensity.

DOI： 10.1109/TPS.2014.2387064

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Nanoscience and Nanotechnology  

Investigation of plasma-organic materials interaction in aqueous solution with atmospheric pressure plasmas have been carried out. Degradation of methylene blue (MB) in aqueous solution via atmospheric pressure He plasma exposure through gas/liquid interface have been investigated. The optical emission spectrum shows considerable emissions of He lines and the emission of O, OH and N radicals attributed to dissociation of water (H<inf>2</inf>O) and air has been confirmed. Structure variation of MB in solution treated with the atmospheric-pressure He plasma has been measured by Fourier transform infrared spectroscopy (FT-IR). The results obtained from FT-IR analysis show degradation of MB in solution treated with the atmospheric-pressure He plasma. The pH effect of MB degradation was investigated using controlled pH solutions by an ultraviolet-visible (UV-Vis) spectroscopy and FT-IR. The results show no effect of MB degradation on pH. The results exhibit that the atmospheric pressure plasmas exposure has made it possible to degrade organic materials in solution due to irradiated radicals from plasma through plasma/liquid interface.

DOI： 10.1166/jnn.2015.10230

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Plasma interactions with organic materials through a plasma/liquid interface have been investigated via the degradation of L-alanine in liquid by irradiation with atmospheric-pressure He plasma. The optical emission spectra of atmospheric-pressure He plasma show considerable emissions of He lines and emissions of O, N, H, and OH radicals attributed to the dissociation of air and water. Variation in the molecular structure of L-alanine in aqueous solution irradiated with the plasma has been observed by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoemission spectroscopy (XPS). The results obtained from FT-IR and XPS analyses show that the atmospheric-pressure He plasma exposure affects the structural variation of L-alanine in solution owing to the oxidation by irradiated radicals from plasma through the plasma/liquid interface.

DOI： 10.7567/JJAP.54.01AF04

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Dye-sensitized solar cells (DSCs) still need wider absorption range despite their stable and good performance. This work proposed the cosensitization of Si quantum dot (QD) and N749 dye for better photo-generation. Si QD was chemically stable with regard to all DSC components and its stability enabled to co-sensitize with dye. Si QDs were fabricated by multihollow discharge plasma chemical vapor deposition and applied for the co-sensitization. Si and dye co-sensitization led to the increase of incident photon to current conversion efficiency and decrease of internal impedance as compared with a standard DSC. As a result, short-circuit current density was increased over 1mA/cm² and the performance was enhanced with co-sensitization from 4.36 to 5.10%. Si and dye co-sensitization was very effective because the enhancement was much larger than the performance of Si QDSC without dye sensitization.

DOI： 10.7567/JJAP.54.01AD02

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We present here the analysis of the discharge characteristics of a He dielectric-barrier-discharge (DBD) plasma jet operated in the frequency range of 0.6 to 30 kHz under an open-air condition. Discharge strength is sensitive to driving voltage frequency, and an increasing driving frequency induces a weak pulse discharge with a small plume length. We also performed time-resolved optical emission measurements in a transient pulse discharge driven by various voltage frequencies. A strong optical emission from O atoms is observed near the quartz-tube outlet at a low driving voltage frequency of about 5 kHz, where more than 90% of the total O emission intensity is detected in the after-discharge period. The observations indicate that low-frequency discharge operation can generate a large number of reactive excited O atoms near the quartz-tube outlet, and this is ascribed to the chemical reactions in the after-discharge period.

DOI： 10.7567/JJAP.53.11RA08

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

Cyclic transport of dust particles (dust hour glass) in a capacitively coupled radio frequency discharge with horizontal electrodes is demonstrated. Dust transport toward the upper electrode is initiated by varying the electrical asymmetry of the discharge. A shaped upper electrode guides dust particles to move toward the center of the discharge. Subsequently, the dust drops through the plasma bulk spontaneously, this way returning to the starting location.

DOI： 10.1109/TPS.2014.2343975

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

A chemical interaction between an atmospheric pressure plasma jet and liquid media is of great interest for biomedical applications. In this paper, the visualization method and typical results of the 2-D distribution of oxidizing substances generated by the plasma jet were reported using the gel visualization reagent. The plasma jet generator consists of a glass tube and two electrodes. As a result, the distribution of oxidizing substances was able to be visualized around the contact point between the plasma jet and the reagent in atmospheric air. The interesting distribution patterns depending on the supplied gas were visually obtained by the reagent. In addition, its relative concentration distribution was also obtained by an absorbance measurement.

DOI： 10.1109/TPS.2014.2325038

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Au counter electrode is generally used with polysulfide electrolyte for quantum dot-sensitized solar cells (QDSCs) due to degradation of QD by iodine electrolyte and strong interaction between Pt counter electrode and S ^2% ions in polysulfide electrolyte. In this work, the effects of the thickness and morphology of Au counter electrode on the performance of Si QDSC were investigated. Au film thickness was linearly controlled from 5 to 500nm by deposition time. Cyclic voltammetry and impedance analysis clarified the catalytic activity of counter electrode, surface resistance of transparent conductive oxide (TCO), and the charge transportation at the counter electrode. The increase of Au film thickness reduced the surface resistance of TCO with increased conductivity. No significant difference in the redox reaction from electrolyte to Si QDs was observed for Au film thickness from 20 to 500 nm. Catalytic reaction of counter electrode was activated with the increase of Au film thickness up to 200 nm. The impedance of charge transportation at the counter electrode was also decreased with Au deposition. Their surface resistance, catalytic activity and internal resistance were reflected in overall performance. Consequently, Si QDSC with 200-nm-thick Au counter electrode had the best performance. © 2014 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.53.05FZ01

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

A dye-sensitized solar cell is one of the representative photochemical solar cells. It has been actively studied and its performance has been much enhanced so far. For better performance, various additional layers such as compact, barrier, and light scattering layers have been applied. Compact and barrier layers suppress the charge recombination with redox electrolyte and light scattering layer improves the light harvesting. Although it was confirmed that these layers were clearly effective for the performance enhancement, there is still a variety of opinions concerning their electrochemical impedance analyses. Therefore, this work tried to analyze their effect on the internal impedance using electrochemical impedance spectroscopy. The most widely used materials were employed for the fabrication of additional layers. TiCl <inf>4</inf> and Zn(NO<inf>3</inf>)<inf>2</inf>â̂™6H <inf>2</inf>O aqueous solutions, and a 400 nm sized TiO<inf>2</inf> were used for compact, barrier, and light scattering layers, respectively. The photovoltaic characteristics confirmed their effect on the performance and their impedance spectra were analyzed according to high, middle, and low frequency bands. As a result, these layers mainly affected the impedance in the middle frequency range because the change of TiO<inf>2</inf>/dye/electrolyte interface was significantly associated with this impedance. Finally, all three layers were applied to a single cell and the performance was considerably increased with reduced charge recombination and improved light harvesting. © 2013 Elsevier B.V.

DOI： 10.1016/j.tsf.2013.08.103

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：International Journal of Precision Engineering and Manufacturing  

This work first introduced Si quantum dots (QDs) for QD-sensitized solar cells (QDSCs). However, the particle size of Si QDs, which had visible light absorption, was relatively large. The paint-type Si QDSC was proposed in this work because Si QDs could not penetrate into nano-porous TiO<inf>2</inf> network. Si QDs were synthesized by multi-hollow plasma discharge CVD and mixed with TiO<inf>2</inf> paste. For better performance, thickness of Si-TiO<inf>2</inf> layer was varied by coating times and Si-TiO<inf>2</inf> films were optically and electrically analyzed. As a result, 6 times screen printed Si-TiO<inf>2</inf> film had the best performance with the smallest internal impedance and the highest photon to current efficiency.

DOI： 10.1007/s12541-014-0343-8

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We report experimental results on correlation between plasma parameters and growth of nanoparticles in capacitively-coupled VHF discharges with amplitude modulation (AM) obtained using two dimensional laser light scattering (LLS) method. Power spectra of floating potential, Ar 810.27?nm emission intensity, and LLS intensity have peaks at the modulation frequency of 100?Hz and its second harmonics, indicating linear correlation between plasma parameters and growth of nanoparticles, that is, their size and/or density. The power spectrum of LLS intensity has another peak at 60?Hz, which coincides with our theoretical prediction of plasma fluctuation induceed nonlinear response of nanoparticle growth.

DOI： 10.7566/JPSCP.1.015083

Crystalline Si nanoparticles were successfully fabricated by a multi-hollow discharge plasma CVD method. Optical band gap of Si-nanoparticle composite films was controlled in a range of 1.6?1.9?eV by the volume fraction of Si nanoparticles in the films. SiN nanoparticle composite films were also successfully produced using a double multi-hollow discharge plasma CVD method in SiH4/H2 and N2 gas mixture. High optical band gap of 2.1?2.2?eV was achieved by adding N atoms to the Si naoparticles.

DOI： 10.7566/JPSCP.1.015080

We have deposited crystalline Ge nanoparticle films using a radio frequency magnetron sputtering method in argon and hydrogen gas mixture under a high pressure condition. Raman spectra and X-ray diffraction pattern of Ge nanoparticle films show a transition from amorphous to crystalline by adding H2 gas.

DOI： 10.7566/JPSCP.1.015082

Si clusters formed in silane discharge plasmas are mainly responsible for light induced degradation of hydrogenated amorphous Si (a-Si:H) thin films deposited by the plasmas. Here we have investigated effects of grid DC bias on incorporation amount of Si clusters into a-Si:H films in multi-hollow discharge plasma CVD reactor using quartz crystal microbalances, by which volume fraction of Si clusters in deposited films is quantitatively measured. When the grid potential is lower than plasma potential, the negatively charged clusters are repelled away from the grid by electrostatic force, resulting in lower volume fraction.

DOI： 10.7566/JPSCP.1.015069

記述言語：日本語   出版者・発行元：The Materials Research Society of Japan  

Dye and quantum dot (QD) are representative sensitizers of the photochemical solar cells. Dye has the highest efficiency in the whole sensitizers. QDs have relatively low performance but their multiple exciton generation enhanced theoretical efficiency from 33 to 44% and expected to achieve high efficiency. This work tried to enhance the photovoltaic performance with the co-sensitization of N719 dye and Si QD. The performance of dye and QD co-sensitized solar cell was not much enhanced because of electron loss of charge recombination. Therefore, TiO2 barrier layer was introduced on TiO2 and Si QD. It blocked the charge recombination with redox electrolyte. It also helped better electron injection from excited dye to TiO2 with strengthened dye adsorption. Consequently, the performance of co-sensitized solar cell was enhanced with reduced charge recombination and increased dye adsorption.

DOI： 10.14723/tmrsj.39.321

CiNii Research

Effects of nitrogen addition to the sputtering atmosphere on crystal growth of ZnO films have been studied. The AFM characterization shows that the nitrogen suppresses the nucleation in the early stage of the crystal growth leading to a non-continue film structure with sparsely distributed grains. As the deposition time increases, the physical properties of the ZnO films are modified by enhancement of adatoms migration at the growing surface, thus homogenous and dense films with larger grain size are obtained. Utilizing these ZnO films as buffer layers with film thickness greater than 4?nm, the electrical resistivity of ZnO:Al films have been significantly decreased from 7.8 × 10?3?Ω?cm to 6.7 × 10?4?Ω?cm.

DOI： 10.7566/JPSCP.1.015064

We have measured spatial profile of flux of dust particles generated due to interaction between H2 plasmas and graphite target in a divertor simulator to study transport mechanism of dust particles. Dust particles were collected on c-Si substrates and observed with a scanning electron microscope. We have found nanostructure of 10?nm in size on the substrate surface. Dust fluxes of both spherical dust particles and flakes are maximum at a position between 80 and 140?mm from the center of the plasma column. The spatial profile of dust flux is determined by the balance between deposition of nanoparticles and their etching by H atoms.

DOI： 10.7566/JPSCP.1.015020

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We propose a simple theoretical model that describes the correlation between plasma fluctuation and fluctuation of nanoparticle growth in reactive plasmas. The model predicts that the high density of nanoparticles brings about small mean size, narrow size dispersion, and sharp size slope on the large side of the size distribution. The model suggests some methods of tuning the size dispersion, and it also suggests that a self-limiting process is the key to markedly suppressing fluctuations in nanostructure fabrication. All predictions coincide with the experimental results reported previously. Moreover, the model suggests that plasma fluctuation induces both the linear and nonlinear responses of nanoparticle growth.© 2014 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.53.010201

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出版者・発行元：電気・情報関係学会九州支部連合大会委員会  

Siは太陽光発電市場の90％以上を占めている代表的な太陽電池材料である．1、2世代型太陽電池研究を主導したSi太陽電池はSi量子ドットをもとにして、次世代型太陽電池への可能性を示している。Siの量子特性は以前研究から証明されたにもかかわらず、多重励起子生成の実現と太陽電池への応用は相変わらず非常に難しい課題である．本研究では，Si量子ドットとポリマーを用いて有・無機ハイブリッド太陽電池を研究した．ポリマーの割合調節を通じてエネルギーバンドをコントロールして、Si量子ドットのバンドギャップに合わせたバンド構造から電荷の抽出が改善された高効率有・無機ハイブリッド太陽電池を作製した。

DOI： 10.11527/jceeek.2014.0_23

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

Quantum dots (QDs) have been attractive recently with their multiple exciton generation characteristics. QD solar cells can more effectively use the incident energy because one or more electrons are generated with the photon of high energy. They have less heat loss and higher theoretical efficiency (44%) than single exciton generation solar cells (33%). This work focused on Si as alternative to conventional QD materials. Si has QD's unique characteristics such as the quantum size effect and quantum confinement with non-toxicity and abundance. Si QDs were fabricated by the multi-hollow discharge plasma chemical vapor deposition and applied to QD-sensitized solar cells (QDSCs). Contrary to the good characteristics of Si QDs, Si QDSCs had poor performance as compared with conventional QDSCs because of the weak combination between Si QDs and TiO<inf>2</inf>. Small amounts of adsorbed Si QD on TiO<inf>2</inf> made low photocurrent and TiO<inf>2</inf> surface widely exposed to redox electrolyte caused charge recombination, the decrease of open-circuit voltage, and low fill factor. For improving their combination, Si QDs were functionalized. The electron transfer from Si to TiO<inf>2</inf> and the bonding with TiO <inf>2</inf> were improved and more Si QDs were adsorbed bythe functionalization. In the functionalization process, the linking source is one of the key parameters. Therefore, 4-vinylbenzoic acid was controlled and its effect was analyzed. The change in the photovoltaic parameters according to the concentration of 4-vinylbenzoic acid and the performance dependence were investigated. In order to verify their characteristics, the effects in terms of the photovoltaic performance, electrochemical impedance, and optical properties were examined. © 2013 Elsevier B.V.

DOI： 10.1016/j.tsf.2013.04.073

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Here, we report the characteristics of a novel organic/inorganic hybrid photovoltaic device using a Si quantum dot (QD) layer synthesized by multihollow discharge plasma chemical vapor deposition. The hybrid device has a p-i-n structure, which consists of a crystalline Si (c-Si) substrate, a Si QD layer, and poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). We have examined the absorption coefficient and photoconductivity of Si QD layers, and confirmed electricity generation from Si QD layers. We have measured the current-voltage characteristics and incident photon-to-current conversion efficiency (IPCE) of c-Si/Si QD/poly(3,4-ethylenedioxythiophene) (PEDOT) hybrid solar cells. This hybrid device shows an energy conversion efficiency of 2.84%, a short-circuit current of 6.84 mA/cm², an open-circuit voltage of 0.73 V, and a fill factor of 0.58. A high IPCE value of 82.8% is obtained at a short wavelength of 460 nm. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.11NA05

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

The volume fraction of silicon clusters in amorphous silicon (a-Si:H) films has been investigated using specially designed quartz crystal microbalances (QCMs) together with optical emission spectroscopy (OES). The optical emission intensities of Si* and SiH* and their intensity ratios are selected for comparison with the QCM results. We show that the volume fraction of silicon clusters strongly correlates with not only the electron temperature but also the SiH* intensity. This suggests that the ratios of Si*/SiH* and SiH* can be used to predict the volume fraction of Si clusters in a-Si:H films. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.11NA07

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We have studied the effects of the N<inf>2</inf> gas flow rate on the surface morphology of ZnO films deposited by the sputtering of a ZnO target using Ar/ N<inf>2</inf>. Height-height correlation function (HHCF) analysis indicates that introducing a small amount of N<inf>2</inf> (<5 sccm) to the sputtering atmosphere enhances adatom migration, leading to a larger grain size in the ZnO films associated with an increase in the lateral correlation length. The HHCF analysis also reveals that films deposited with and without N <inf>2</inf> exhibit a self-affine fractal surface structure. We demonstrate that utilizing such ZnO films deposited using Ar/N<inf>2</inf> as buffer layers, the crystallinity of ZnO:Al (AZO) films on the buffer layers can be greatly improved. The electrical resistivity of 100-nm-thick AZO films decreases from 1.8 × 10^-3 to 4:0 × 10^-4 Ω·cm by utilizing a ZnO buffer layers prepared at N<inf>2</inf> flow rate of 5 sccm. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.11NB03

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Epitaxial ZnInON (ZION) films with a tunable band gap have been successfully fabricated by RF magnetron sputtering on ZnO templates prepared via nitrogen mediated crystallization (NMC). X-ray diffraction (XRD) measurements show that the full widths at half maximum of the rocking curves from (002) and (101) planes are small at 0.10 and 0.08°, respectively, indicating a high crystallinity with good in-plane and out-of-plane alignments. Since the coherent growth of 35-nm-thick ZION films on NMC-ZnO templates is deduced from the reciprocal space mapping around the (105) diffraction, there is little lattice relaxation at the interface between the films and templates, which is significant in terms of the suppression of carrier recombination. The band gap of the ZION films has been tuned in a wide range of 1.7-3.3 eV by changing the Zn:In ratio. These results indicate that ZION is a potential absorption layer material of solar cells. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.11NM06

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Flux control of dust particles in a nanometer size range using dc bias voltage is discussed based on dust collection in a divertor simulator employed helicon hydrogen discharges. To discuss mechanisms of flux control, we have estimated etching rate of deposited dust particles due to hydrogen plasma irradiation and have measured current density toward the dc biased substrates. We have found the contribution of the etching can be negligible in a dc bias voltage V<inf>bias</inf> range between -50 and 70 V. Clear correlation between V<inf>bias</inf> dependence of current density and that of dust flux shows electrostatic force is one of important forces for controlling flux of dust particles. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.11NA08

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Japanese Journal of Applied Physics  

In dye-sensitized solar cells, nanoporous structure of TiO<inf>2</inf> is very important for efficient cell because lots of dye molecules are adsorbable and they are the source of the photocurrent. However, the internal impedance of TiO<inf>2</inf> is relatively large and it limits the performance. For better performance, vanadium was doped into TiO<inf>2</inf> in this work. Doping different material generally improves the characteristics and functions of original materials. Vanadium doping has some advantages such as the reduction of internal resistance, the improvement of chemical stability and high absorption. Especially, reduced internal resistance is so helpful for better electron transfer in TiO<inf>2</inf> network. Various amounts of vanadium were applied and photovoltaic performance, internal impedance and absorbance were measured in order to verify the effect of vanadium doping. As a result, vanadium doping improved the overall performance from 6.01 to 6.81% with decreased internal resistance although adsorbed dye amount was reduced by decreased surface area and open circuit voltage was also decreased by the change of band-gap energy. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.11NM02

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

We have studied photocurrent generation in Si quantum-dot (QD) sensitized solar cells, where QD thin films composed of Si nanoparticles were deposited using the double multi-hollow discharge plasma chemical vapor deposition process in an SiH<inf>4</inf>/H<inf>2</inf> and CH<inf>4</inf> or N<inf>2</inf> gas mixture. The short-circuit current density of the Si QD sensitized solar cells increases by a factor of 2.5 by using Si nanoparticles prepared by irradiation of CH<inf>4</inf> or N<inf>2</inf> plasma onto the Si nanoparticle surface. We have measured incident photon-to-current conversion efficiency (IPCE) in the near-ultraviolet range using quartz-glass front panels of the QD sensitized solar cells. With decreasing the wavelength of irradiation light, IPCE gradually increases upon light irradiation in a wavelength range less than about 600 nm, and then steeply increases below 300 nm, corresponding to 2.2 times the optical band-gap energy of Si QD film. © 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2013.04.111

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Quantum dots (QDs) have attracted much attention with their quantum characteristics in the research field of photochemical solar cells. Si QD was introduced as one of alternatives to conventional QD materials. However, their large particles could not penetrate inside TiO<inf>2</inf> layer. Therefore, this work proposed the paint-type Si QD-sensitized solar cell. Its heat durability was suitable for the fabrication of paint-type solar cell. Si QDs were fabricated by multihollow discharge plasma chemical vapor deposition and characterized. The paste type, sintering temperature, and Si ratio were controlled and analyzed for better performance. Finally, its performance was enhanced by ZnS surface modification and the whole process was much simplified without sensitizing process. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.10MB07

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We have succeeded to deposit anisotropic and top surface deposition profile on substrates with trenches using H-assisted plasma CVD of Ar + H2 + C7H8 at a low substrate temperature of 100 oC. For the anisotropic deposition profile, carbon is deposited without being deposited on sidewall of trenches. For the top surface deposition profile, carbon is deposited at only top surface. The optical emission measurements and evaluation of deposition rate have revealed that a high flux of H atmos is the key to the deposition profile control. The mass density of the films and their Raman spectrum have shown that their structure is a-C:H.

High quality ZnO:Al (AZO) films have been obtained by utilizing buffer layers fabricated via nitrogen mediated crystallization (NMC), where sputtering method is employed for preparation of both buffer layers and AZO films. Introduction of small amount of N2 (N2/(Ar+N2) = 16%) to the sputtering atmosphere of NMC-ZnO buffer layers drastically improves the crystallinity of buffer layers and thus AZO films. The most remarkable effect of the buffer layers is a significant reduction in the resistivity at high base pressure of background gases. The resistivity of conventional AZO films increases from 2.0 m??cm to 70.0 m??cm with increasing the base pressure from 3×10-5 Pa to 1×10-3 Pa, while the resistivity of AZO films with NMC buffer layers increases from 0.5 m??cm to 2.0 m??cm, where the thickness of AZO film is 88 nm. Furthermore, AZO films with a sheet resistance of 10 ?/? and an optical transmittance higher than 80% in a wide wavelength range of 400?1100 nm have been obtained.

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Surface and Coatings Technology  

We investigated the effects of incorporation of crystalline nanoparticles on properties of microcrystalline Si films deposited using multi-hollow discharge plasma CVD. Both photo and dark conductivity of films with nanoparticles are lower than the films without nanoparticles. Films with nanoparticles have higher photosensitivity than those of films without nanoparticles in a low crystallinity region. Microcrystalline films of high crystallinity and high photosensitivity are obtained only in a range of small volume fraction of nanoparticles under low dilution ratio, R=([SiH<inf>4</inf>]+[H<inf>2</inf>])/[SiH<inf>4</inf>]. Incorporation of small amount of nanoparticles into films strongly affects photo and dark conductivity of films. © 2012 Elsevier B.V.

DOI： 10.1016/j.surfcoat.2012.04.029

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Surface and Coatings Technology  

In order to obtain high density carbon films with keeping anisotropic deposition profile on trench substrates, we control mass density of carbon films deposited by a H-assisted plasma chemical vapor deposition (CVD) method by ion kinetic energy of ions irradiating on film surface during deposition. The highest mass density of 2.14g/cm³ is obtained for deposition under the ion energy of 75eV and it is 1.4 times as high as that for the ion energy of 32eV. We also have studied etching rate of these films using H<inf>2</inf>+N<inf>2</inf> discharge plasmas. The lowest etch rate of 1.8nm/min is obtained for the ion energy of 75eV and it is 2.8 times as low as that for the ion energy of 32eV. Etching rate of carbon films decreases exponentially with increasing the mass density of carbon films. Control of ion energy is the key to obtain high mass density carbon films with keeping anisotropic deposition profile on trench substrates. © 2012 Elsevier B.V.

DOI： 10.1016/j.surfcoat.2012.10.002

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Time evolution of spatial profile of nanoparticle amount in low pressure reactive discharge plasmas have been measured to study effects of amplitude modulation of the plasmas on particle growth in the initial growth phase. Amplitude modulation of discharge voltage leads to oscillate nanoparticle amount and their spatial profile. Growth of nanoparticles is suppressed by increasing the AM frequency.

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Nuclear Materials  

In fusion devices, dust particles are generated due to plasma-wall interactions and may cause safety or operational problems. Therefore it is necessary to clarify the generation and transport mechanisms of dust particles. Here we have measured energy influx from H<inf>2</inf> plasmas toward a graphite target using a calorimetric probe and compared the results with the dust flux toward a dust collecting substrate set on the reactor wall. The dust flux decreases with increasing the energy influx. For the higher discharge power, the more number of dust particles tend to redeposit onto the graphite target due to the higher ion drag force and hence the dust flux toward the reactor wall becomes smaller. The results show that dust inventory depends strongly on energy influx to graphite divertor plates in fusion devices. © 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jnucmat.2013.01.169

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記述言語：英語   出版者・発行元：Journal of Nuclear Materials  

We measured the dependence of the collected flux of dust particles on the bias potential Δφ with respect to ground in the Large Helical Device at the National Institute of Fusion Science. This is a first step toward developing a novel method for removing dust for fusion reactors based on applying a local bias potential. The collected dust particles were classified into two kinds: spherical carbon particles smaller than 300 nm and stainless-steel flakes smaller than 1 μm. For Δφ = -70 to +70 V, the flux of spherical particles increased exponentially with increasing Δφ. The flux of flakes increased when Δφ was increased from -70 V to +30 V and it decreased at higher Δφ. These results suggest that this method is useful for removing carbon and metal dust particles from the shadow area of fusion devices using appropriate control of the local bias potential. © 2013 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jnucmat.2013.01.154

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記述言語：英語   出版者・発行元：Journal of Physics D Applied Physics  

The control of the spatial distribution of micrometre-sized dust particles in capacitively coupled radio frequency discharges is relevant for research and applications. Typically, dust particles in plasmas form a layer located at the sheath edge adjacent to the bottom electrode. Here, a method of manipulating this distribution by the application of a specific excitation waveform, i.e. two consecutive harmonics, is discussed. Tuning the phase angle θ between the two harmonics allows one to adjust the discharge symmetry via the electrical asymmetry effect (EAE). An adiabatic (continuous) phase shift leaves the dust particles at an equilibrium position close to the lower sheath edge. Their levitation can be correlated with the electric field profile. By applying an abrupt phase shift the dust particles are transported between both sheaths through the plasma bulk and partially reside at an equilibrium position close to the upper sheath edge. Hence, the potential profile in the bulk region is probed by the dust particles providing indirect information on plasma properties. The respective motion is understood by an analytical model, showing both the limitations and possible ways of optimizing this sheath-to-sheath transport. A classification of the transport depending on the change in the dc self-bias is provided, and the pressure dependence is discussed. © 2013 IOP Publishing Ltd.

DOI： 10.1088/0022-3727/46/24/245202

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Electrochimica Acta  

Quantum dot-sensitized solar cell (QDSC) based on multiple exciton generation of QD has been expected to realize high efficiency. This work focused on Si QD instead of conventional QD materials because of their toxicity and scarcity. Si QDs were fabricated by multi-hollow discharge plasma chemical vapor deposition. General QDSCs use polysulfide electrolyte because it is suitable for stabilizing QDs and its redox reaction is the best as compared with other redox systems. The improvement of redox reaction which is one of the slowest reactions in the kinetic analysis is closely connected with the enhancement of performance. For the enhancement on the overall performance of Si QDSC, the performance dependence on electrolyte composition was investigated. The concentrations of Na<inf>2</inf>S and S were varied for the activation of redox reaction and KCl concentration was optimized for the improvement of electrolyte characteristics. Consequently, the best performance of Si QDSC was obtained with 1 M Na<inf>2</inf>S, 2 M S, and 0.4 M KCl polysulfide electrolyte. © 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2013.02.026

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Electrochimica Acta  

Multiple exciton generation solar cell based on quantum dots has higher theoretical efficiency than single exciton generation solar cell. In this work, Si quantum dots with the diameter of 10 nm were fabricated by the multi-hollow discharge plasma chemical vapor deposition and applied to the quantum dot-sensitized solar cell. In this cell, there was considerable electron recombination with redox electrolyte in the Si-TiO<inf>2</inf> network because of large Si particle size. For the reduction of recombination and the enhancement of performance, a barrier layer was introduced. Zinc nitrate hexahydrate (Zn(NO<inf>3</inf>)<inf>2</inf>·6H<inf>2</inf>O) and zinc acetate dihydrate (Zn(CH<inf>3</inf>COO)<inf>2</inf>·H<inf>2</inf>O) were employed as precursors for surface modification. Consequently, short circuit current and open circuit voltage of the cells were increased by the surface modification with both precursors. The improvement was ascribed to the inhibition of electrons back transfer from TiO<inf>2</inf> to the electrolyte by the barrier layer. This result clearly demonstrated that the surface modification with ZnO was advantageous for the performance enhancement. © 2012 Elsevier Ltd.

DOI： 10.1016/j.electacta.2012.09.087

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記述言語：日本語   出版者・発行元：The Surface Science Society of Japan  

This paper reviews production of nanoparticles using low pressure reactive plasmas and its application to quantum dot sensitized solar cells. For the method, nanoparticles of several nm in size with a small size dispersion are produced in gas phase using reactive plasmas, and then the nanoparticles and radicals are co-deposited on a substrate. This method realizes one-step deposition of nanoparticle composite films in a controllable way.

DOI： 10.1380/jsssj.34.520

Open Access

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Fusion Engineering and Design  

The collection of dust particles using divertor simulation helicon plasmas has been carried out to examine dust formation due to the interaction between a graphite target and deuterium plasmas, which are planned to operate in the large helical device (LHD) at the Japanese National Institute for Fusion Science (NIFS). The collected dust particles are classified into three types: (i) small spherical particles below 400 nm in size, (ii) agglomerates whose primary particles have a size of about 10 nm, and (iii) large flakes above 1 μm in size. These features are quite similar to those obtained through hydrogen plasma operation, indicating that the dust formation mechanisms due to the interaction between a carbon wall and a plasma of deuterium, which is the isotope of hydrogen, is probably similar to those of hydrogen. © 2012 Elsevier B.V.

DOI： 10.1016/j.fusengdes.2012.10.002

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

Hydrogenated ZnO thin films have been successfully deposited on glass substrates via a nitrogen mediated crystallization (NMC) method utilizing RF sputtering. Here we aim to study the crystallinity and electrical properties of hydrogenated NMC-ZnO films in correlation with substrate temperature and H <inf>2</inf> flow rate. XRD measurements reveal that all the deposited films exhibit strongly preferred (001) orientation. The integral breadth of the (002) peak from the hydrogenated NMC-ZnO films is smaller than that of the conventional hydrogenated ZnO films fabricated without nitrogen. Furthermore, the crystallinity and surface morphology of the hydrogenated NMC-ZnO films are improved by increasing substrate temperature to 400 °C, where the smallest integral breadth of (002) 2θ-ω scans of 0.83° has been obtained. By utilizing the hydrogenated NMCZnO films as buffer layers, the crystallinity of ZnO:Al (AZO) films is also improved. The resistivity of AZO films on NMC-ZnO buffer layers decreases with increasing H<inf>2</inf> flow rate during the sputter deposition of buffer layers from 0 to 5 sccm. At a H<inf>2</inf> flow rate of 5 sccm, 20-nm-thick AZO films with low resistivity of 1.5 × 10.3 Ωcm have been obtained. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.01AC08

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.7567/JJAP.52.01AB01

Web of Science

記述言語：英語   出版者・発行元：Japanese Journal of Applied Physics  

Quantum dots (QDs) based on multiple exciton generation have attracted much attention. They are capable of generating multiple electrons by single-photon absorption. Si is one of the good QD sources and its nontoxicity and abundance are advantageous for photovoltaics. In this work, Si QDs were fabricated by multihollow discharge plasma chemical vapor deposition, and they were applied to Si QD-sensitized solar cells. Their initial performance was poor because of the weak adhesion of Si and charge recombination. In this work, we solved these problems through the functionalization of Si QDs and a ZnO barrier. Functionalized Si QDs were more adsorbed on TiO<inf>2</inf> with strengthened adhesion and the ZnO barrier prevented the contact between TiO<inf>2</inf> and the redox electrolyte. Consequently, the improved adhesion and the reduced electron recombination led to the enhancement of overall photovoltaic characteristics. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.01AD05

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We have carried out in-situ measurements of Si cluster volume fraction in Si films during plasma chemical vapor deposition by using quartz crystal microbalances (QCM's) together with a cluster-eliminating filter. The cluster volume fraction in films is deduced from film deposition rates with and without Si clusters using QCM's. By employing this method we have revealed a depth profile of the Si cluster volume fraction. A high cluster volume fraction is observed in the initial phase of film deposition. This behavior is compared with time evolution of SiH*, Si* emission intensities and their intensity ratio. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.01AD01

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DOI： 10.7567/JJAP.52.01AB01

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出版者・発行元：Japanese Journal of Applied Physics  

Etching resistance of carbon films deposited by plasma chemical vapor deposition (CVD) is one of the concerns to fabricate nanostructures using such carbon films as protective coating films and dummy films. We have carried out H<inf>2</inf>/N<inf>2</inf> plasma etching of carbon films deposited by using an H-assisted plasma CVD method. The etching rate of carbon films decreases exponentially with increasing the mass density of carbon films from 1.51 to 2.27 g/cm³. The mass density of carbon films is the key parameter to tune the etching resistance. © 2013 The Japan Society of Applied Physics.

DOI： 10.7567/JJAP.52.01AB01

Scopus

出版者・発行元：電気・情報関係学会九州支部連合大会委員会  

薄膜シリコン太陽電池は、現在アモルファスシリコン太陽電池をトップセル、微結晶シリコン太陽電池をボトムセルとしたタンデムセルが用いられている。タンデムセルが、太陽電池市場で大きなシェアを得るためには、トップセルの光劣化を抑制する必要がある。光劣化の原因として、シランプラズマ中で発生するナノ粒子の膜への取り込みが指摘されている。本研究では、我々が開発したナノ粒子体積分率その場計測法を用いて、製膜初期におけるナノ粒子取り込み量に対する振幅変調放電の効果について研究した。

DOI： 10.11527/jceeek.2013.0_453

CiNii Research

出版者・発行元：電気・情報関係学会九州支部連合大会委員会  

プロセシングプラズマにおいて、加工寸法の微細化に伴いナノ構造との界面制御が近年重要視されている。筆者等はプラズマ中の微粒子をナノ界面のモデルとして、微粒子に対するプラズマ作用について研究している。本研究の実現にあたって、単一微粒子をプラズマ中で保持し、1つの微粒子に対するプラズマ作用のその場計測が必要である。筆者等はレーザートラップ法を用いて、単一微粒子をプラズマ中で保持することに成功し、またプラズマ照射中の微粒子のラマン分光計測にも成功したので、これを報告する。

DOI： 10.11527/jceeek.2013.0_452

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

We investigate uniformity of radial density profile of nano-particles in capacitively-coupled radio frequency discharge with an amplitude modulation (AM) of rf discharge voltage, by a two-dimensional laser light scattering method. Their densities at the center and that at the edge of the electrode increase by 3 and 24 times when the amplitude modulation level increases from 0 (without AM) to 30%. The uniformity of radial density profile of nano-particles is significantly improved by using the AM method. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2012.07.059

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

We investigated effects of incorporation of Si crystalline nanoparticles into microcrystalline Si films during their deposition on their growth, structure and properties using multi-hollow discharge plasma chemical vapor deposition. The films with nanoparticles show a lower (220) orientation ratio than those without nanoparticles, whereas both the films have nearly the same film thickness and crystallinity. The films with nanoparticles have inverted conical growth, while the films without nanoparticles have columnar growth. Nucleation density of the films with nanoparticles is higher than that of the films without nanoparticles. Both photo and dark conductivities of the films with nanoparticles tend to be lower than those without nanoparticles. Thus, incorporation of small amount of nanoparticles into microcrystalline Si film affects growth, structure and properties of the films. © 2012 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2012.06.023

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plasma Sources Science and Technology  

Transport of micrometer-sized dust particles in a capacitively coupled radio frequency discharge at low pressures of a few Pa is realized experimentally and understood by a kinetic particle simulation combined with a model. Applying a voltage waveform, which consists of two consecutive harmonics with a variable phase angle, θ, to one electrode, control of both the spatial potential profile and the ion density distribution is obtained by adjusting θ. In this way, the electrostatic and ion drag forces, on dust particles initially located at the sheath edge adjacent to the lower electrode, are controlled. The sudden change of θ leads to an abrupt change of the sheath width. This introduces the particles instantaneously into a high potential that accelerates them to high kinetic energies. The experimental results show that a certain minimum change of the discharge symmetry, i.e. of the phase angle, is required to allow the transport of dust particles through the plasma bulk. Beyond this threshold, a part of the transported particles can even be trapped around the edge of the opposing (upper) sheath. © 2012 IOP Publishing Ltd.

DOI： 10.1088/0963-0252/21/3/032001

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

High quality epitaxial ZnO films on sapphire (110) plane have been fabricated on ZnO homo-buffer layers crystallized via solid-phase epitaxially (SPE). The SPE-ZnO films are fabricated by annealing of amorphous ZnON (a-ZnON) films deposited by RF magnetron sputtering. During annealing, the a-ZnON films are oxidized and converted to ZnO crystal. X-ray diffraction (XRD) analysis shows that the resultant films are epitaxially grown on the sapphire substrates. By using the SPE-ZnO films as homo-buffer layers, the ZnO films with high crystallinity, which are deposited by RF magnetron sputtering, are fabricated. The full width at half-maximum of XRD patterns for 2θ-ω and ω scan of (002) plane are 0.094° and 0.12°, respectively, being significantly small compared with 0.24° and 0.55° for the films without buffer layers. Thus utilizing SPE buffer layers is very promising to obtain epitaxial ZnO films with high crystallinity. © 2011 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2011.10.136

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記述言語：英語   出版者・発行元：Journal of Instrumentation  

We have developed a simple in-situ method for measuring the size distribution (the mean size (mean diameter) and size dispersion) of nano-particles generated in reactive plasmas using the 2 dimensional laser light scattering (2DLLS) method. The principle of the method is based on thermal coagulation of the nano-particles, which occurs after the discharge is turned off, and the size and density of the nano-particles can then be deduced. We first determined the 2D spatial distribution of the density and size of the nano-particles in smaller particle size (a few nm) range than ones deduced from the conventional 2DLLS method. From this 2D dataset, we have for the first time been able to determine the size distribution of nano-particles generated in a reactive plasma without ex-situ measurements. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

DOI： 10.1088/1748-0221/7/04/C04017

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Materials Transactions  

Plasma display panels (PDPs) with a SrCaO protective layer of high secondary electron emission coefficient were manufactured using the "all-in-vacuum" process, whereby the protective layer deposition and panel sealing were performed continuously in high vacuum in order to keep the surface of the protective layer as clean as possible. The PDP with the SrCaO protective layer manufactured using the "all-in-vacuum" process ("all-in-vacuum" SrCaO-PDP) for Ne20 vol% Xe exhibited a luminance 2.1 times larger, a luminous efficacy 1.7 times larger, and the same discharge time lag, compared with the PDP with the MgO protective layer manufactured using the conventional process (conventional MgO-PDP) for Ne4 vol% Xe, which had almost the same discharge voltage. © 2012 The Japan Institute of Metals.

DOI： 10.2320/matertrans.M2011181

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記述言語：英語   出版者・発行元：The Materials Research Society of Japan  

Effects of N2/Ar gas flow rate ratio on the crystallinity of sputtered ZnO films fabricated via nitrogen mediated crystallization (NMC) have been clarified. Introduction of small amount of N2?(N2/Ar = 4/20.5 sccm) drastically improves the crystal orientation and enlarges grain size of the NMC-ZnO films, where FWHM of XRD patterns for 2θ-ω and ω scan of (002) plane are 0.17° and 2.6°, respectively. A further increase in N2/Ar flow rate ratio deteriorates the crystallinity, since excess N atoms in the films disarrange the crystal structure of ZnO. Furthermore, ZnO:Al (AZO) films with high crystallinity have been successfully fabricated by utilizing the NMC-ZnO films deposited at N2/Ar = 4/20.5 sccm as buffer layers. 100-nm-thick AZO films with a resistivity of 6.8×10-4?Ωcm and an optical transmittance higher than 80% in a wide wavelength range of 500 nm to 1500 nm has been obtained.

DOI： 10.14723/tmrsj.37.165

CiNii Research

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

A high-pressure depletion method using plasma chemical vapor deposition (CVD) is often used to deposit hydrogenated microcrystalline silicon (c-Si:H) films of a low defect density at a high deposition rate. To understand proper deposition conditions of c-Si:H films for a high-pressure depletion method, Si films were deposited in a combinatorial way using a multihollow discharge plasma CVD method by which fluxes of H and SiH3 radicals and their flux ratio can be varied with the distance from the discharges. The higher gas pressure brings about the higher deposition rate, whereas the process window of device quality -c-Si:H films becomes quite narrower for the higher gas pressure. © 2012 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.51.01AD02

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記述言語：英語   出版者・発行元：Japanese Journal of Applied Physics  

We have deposited cluster-free B-doped hydrogenated amorphous silicon (a-Si:H) films using a SiH4+B10H14 multi-hollow discharge plasma chemical vapor deposition (CVD) method. We have studied the dependence of the deposition rate, band gap, and conductivity of the films on the gas flow rate ratio R =B <inf>10</inf>H <inf>14</inf>)=SiH <inf>4</inf>. The deposition rate for SiH4+B10H14 plasmas is 2-3 times as high as that for pure SiH4 plasmas. Optical emission spectroscopy (OES) measurements indicate that SiH3 radical generation rate remains nearly constant regardless of R. These results suggest that BxHy radicals enhance the surface reaction probability and/or sticking probability of SiH <inf>3</inf>, being the predominant deposition precursor. Cluster-free B-doped a-Si:H films have a wide band-gap energy of 1.8-2.0 eV and a conductivity as high as 5:0 × 10 ^-6 S/cm. These results demonstrate that cluster-free B-doped a-Si:H films deposited using SiH4+B10H14 multi-hollow discharge plasma CVD are promising as a p-layer of pin a-Si:H solar cells. © 2012 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.51.01AD03

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Japanese Journal of Applied Physics  

We developed Si quantum-dot (QD) sensitized solar cells using nitridated Si nanoparticle films. The Si/N content ratio of the Si nanoparticle films was combinatorially controlled in double multi-hollow discharge plasma chemical vapor deposition (CVD) process in a SiH <inf>4</inf>/H <inf>2</inf> and N <inf>2f</inf> gas mixture. The short-circuit current density of Si QD sensitized solar cells increases by a factor of 1.3 with the nitridation of Si nanoparticles, and a high photon-to-current conversion efficiency of 40% was achieved at a short wavelength of 350 nm. © 2012 The Japan Society of Applied Physics.

DOI： 10.1143/JJAP.51.01AD01

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Journal of the Vacuum Society of Japan  

We developed a new PDP manufacturing method in which protective layer deposition and sealing were performed continuously in high vacuum (pressure range 10 ^-6 Pa), to keep the protective layer surface as clean as possible ("all-in-vacuum"). The "all-in-vacuum" panel shows high performance: 1) short aging time, 2) low firing voltage, and 3) short statistical time lag. Especially, the short statistical time lag is not obtained once the MgO layer is annealed in ambient air, even though the annealed MgO layer is activated in high vacuum.

DOI： 10.3131/jvsj2.55.125

Scopus

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

We have investigated the effects of plasma fluctuation on the growth of nanoparticles in capacitively-coupled rf discharges with amplitude modulation (AM). Nanoparticles grow more slowly for higher AM levels, which causes the density of nanoparticles to increase by 100% and their size to decrease by 23%. The increase in the number of radicals for nucleation and nanoparticles by AM is thought to cause a decrease in the radical flux for a nanoparticle because the rate of increase in the number of radicals is smaller than that of nanoparticles. Therefore, this causes the generation of a large amount of nanoparticles with small sizes. © 2011 The Japan Society of Applied Physics.

DOI： 10.1143/APEX.4.105001

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

We have deposited Si thin films using a multi-hollow discharge plasma CVD method to compare properties of the films with and without incorporating crystalline Si nanoparticles into the films. After the deposition of the films, we have evaluated crystallization of the films by irradiating laser. We have found that a laser power at which crystalline Si nanoparticles embedded a-Si:H films start to be crystallized is lower than that for a-Si:H films without the nanoparticles. The incorporation of the nanoparticles has no effect on the defect density of the films. These results suggest incorporation of crystalline Si nanoparticles into the films play a role of crystallization of Si films during the deposition. © 2011 Elsevier B.V.

DOI： 10.1016/j.tsf.2011.01.408

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Physics D Applied Physics  

We propose the concept of 'nano-factory in plasma' which is a miniature version of a macroscopic conventional factory. A nano-factory in plasma produces nanoblocks and radicals (adhesives) in reactive plasmas, transports nanoblocks towards a substrate and arranges them on the substrate. We describe several key control methods for a nano-factory in plasma: size and structure control of nanoparticles, control of their agglomeration, transport and sticking, and then explain the combination of several types of control. Finally we point out remaining important issues in nano-factories in plasma. © 2011 IOP Publishing Ltd.

DOI： 10.1088/0022-3727/44/17/174038

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We collected dust particles generated by interaction between a plasma and a carbon target in helicon discharge reactor, by which diverter plasmas in fusion devices are simulated. The dust particles are classified into three kinds: small spherical particles, agglomerates, and large flakes, suggesting three formation mechanisms: chemical vapor deposition (CVD) growth, agglomeration, and peeling from redeposited layer on the reactor wall. The area density and flux towards substrates of dust particles exponentially increase with the substrate bias voltage. The energy influx of plasmas towards the target and ion density were measured to clarify the dust formation mechanisms. They are nearly constant irrespective of the substrate bias voltage suggesting that the production rate of dust particles does not depend on the substrate bias voltage and their collection efficiency does.

A combinatorial technique using a multi-hollow discharge plasma CVD method has been employed to investigate effects of substrate temperature on hydrogenated microcrystalline silicon (?c-Si:H) film growth. No film is deposited near the discharge region RT to 350°C, whereas the area of no film region decreases with increasing the substrate temperature. This is attributed to competitive reactions between Si etching by H atoms and Si deposition. The area of microcrystalline Si region increases with the substrate temperature due to high surface diffusion rate of Si containing radical. These results show that the process window of μc-Si:H films becomes wider for the higher substrate temperature due to two reasons: 1) the lower Si etching rate and 2) the longer surface migration length of Si containing radicals. The defect density decreases significantly with increasing Ts from 6.24 × 10 16 cm -3 for Ts =100 o C down to 6.26 × 10 15 cm -3 for T s =300 o C.

We have succeeded in deposition of highly stable a-Si:H films at a rate of 3 nm/s. To evaluate their performance as an I layer of PIN solar cells, Fill Factor (FF) of N-type c-Si/a-Si:H/Ni Schottky cells with cluster free a-Si:H films were measured. High quality stable a-Si:H films, were deposited with a multi-hollow discharge plasma CVD reactor together with a cluster-eliminating filter. Initial FF of the cell is 0.521, whereas stabilized FF is 0.495 that is 4.99% lower than the initial FF. Our multi-hollow discharge plasma CVD method is useful to fabricate highly stable a-Si:H solar cells.

We have investigated effects of nanoparticle inclusion on properties of a-Si:H films and mc-Si:H films using the multi-hollow discharge plasma CVD method. Minor deposition species (nanoparticles in this study) modify considerably properties of a-Si:H films and mc-Si:H films

Effects of N2/Ar flow rate ratio on properties of ZnO films fabricated via nitrogen mediated crystallization (NMC) have been studied. NMC-ZnO films are deposited by RF magnetron sputtering using Ar-N2 mixed gas. X-ray diffraction (XRD) analysis shows that the crystallinity of NMC-ZnO films is improved by addition of a small amount of N2 to sputtering atmosphere (N2/(Ar+N2) flow ratio of 8%). By using the NMC-ZnO films as homo-buffer layers, ZnO films with high crystallinity are deposited by RF magnetron sputtering. The full width at half-maximum of XRD patterns for ω scan of (002) plane are 0.061°, being significantly small compared with 0.49° for the films without buffer layers. A further increase in N2/Ar flow rate ratio deteriorates the crystallinity because excess N atoms in the films disarrange the crystal structure of ZnO. The results indicate that utilizing NMC buffer layers deposited at an adequate N2 partial pressure is very promising to obtain epitaxial ZnO films with high crystallinity.

Effects of electrolyte on performance of Si QDSCs were investigated. We successfully fabricated an efficient polysulfide electrolyte based on the solvent mixed with water and methanol at a volume ratio of 3:7. The optimal electrolyte contains 1.0M Na2S, 0.5M S and 0.2M KCl. By introducing different ingredients with proper concentration, Jsc, Voc and fill factor are much improved. The efficiency of Si QDSCs using optimized electrolyte is 0.027%

Low resistive ZnO:Al (AZO) films with uniform spatial distribution have been obtained by utilizing buffer layers fabricated by Ar/N2 magnetron sputtering. For 100 nm-thick AZO films, the averaged grain size of AZO films with buffer layers is 65 nm, which is 1.8 times larger than that of the films without buffer layers. This increase in the grain size of AZO films is due to the low grain density of buffer layers. As a result, the resistivity is drastically reduced. At the area facing the target erosion, the resistivity reduced from 2.27 m??cm for the films without buffer layers to 0.50 m??cm for our films, consequently, the spatial distribution of the resistivity is significantly improved. These results reveal that our method described here is full of promise for fabrication of ZnO-based TCO materials.

Effects of nano-particles on formation kinetics of microcrystalline silicon films were studied by X-ray diffraction spectroscopy (XRD) and optical emission spectroscopy (OES). Volume fraction of (220) orientation crystals of films without incorporating nano-particles is higher than that of those with nano-particles. The IH?/ISi* value in the region with nano-particles is slightly higher than that in the region without nano-particles. The ISi*/ISiH* value is almost the same as that in the region with and without nano-particles. These results suggest that (220) orientation crystal growth is suppressed by incorporation of nano-particles.

We have investigated effects of plasma fluctuation on the growth of nanoparticles in capacitively-coupled rf discharges with amplitude modulation. Nanoparticles grow more slowly for higher AM levels, that is they have 7 times higher density and 23% smaller size. This AM method is useful for the production of a large amount of nanoparticles with a small size

To evaluate radical fluxes for microcrystalline silicon film deposition, Si films were deposited in a combinatorial way using a multi-hollow discharge plasma CVD method. Film crystallinity varied with the distance from the powered electrode. Based on the film deposition rate and Raman crystallinity, we proposed a method to estimate hydrogen flux. This evaluation of hydrogen flux is one of useful way to understand a process window of ?c-Si:H films.

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Applied Physics Express  

We propose a novel method of oxide crystal growth via atomic-additive mediated amorphization. By utilizing this method, solid-phase crystallization (SPC) of ZnO from amorphous phase has been successfully demonstrated via nitrogen atom mediation. The resultant SPC-ZnO films are highly orientated and the crystallinity is higher than that of the films prepared by conventional sputtering. By using the SPC-ZnO as a buffer layer, the resistivity of ZnO:Al (AZO) films is drastically decreased. 20-nm-thick AZO films with a resistivity of 5 × 10^- ω cm and an optical transmittance higher than 80% in a wide wavelength range of 400-2500 nm have been obtained. © 2011 The Japan Society of Applied Physics.

DOI： 10.1143/APEX.4.011101

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Aip Conference Proceedings  

We present production of surface nitridated silicon nano-particle composite films for efficient multi exciton generation. Nitridation of silicon nano-particles were produced using double multi-hollow discharge plasma CVD, where generation of silicon nano-particles and their nitridation were independently performed using SiH<inf>4</inf>/H<inf>2</inf> and N<inf>2</inf> multi-hollow discharge plasmas. We succeeded in controlling nitrogen contents in silicon nano-particle composite films by varying flux of N radicals irradiated to silicon particles. We also observed strong photoluminescence emission centered at around 700 nm from the films. The PL signal may be attributed to the recombination of exciton confined in silicon nano-p articles. © 2011 American Institute of Physics.

DOI： 10.1063/1.3653600

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出版者・発行元：電気・情報関係学会九州支部連合大会委員会  

プラズマと材料のナノ界面における相互作用を解明・制御するモデル実験として、反応性プラズマ中のナノ粒子のサイズ分布に注目した[1-3]。実験では容量結合高周波放電により生成した。反応性プラズマ中でナノ粒子を発生成長させ、そのサイズ分に対するAM変調の効果を調べ,AM変調によりサイズ分布が狭くなる結果が得られた。

DOI： 10.11527/jceeek.2011.0_610

CiNii Research

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

We present here measurements of high Xe-contents plasma display panel (PDP) with SrCaO cold cathode. Luminous efficacy (η) shows a two-step increase with Xe-concentration in Ne/Xe gas mixture: η drastically increases up to Xe-concentration of 30% (Xe: 30%), and then attains 5 lm/W at the highest Xe-concentration of Xe: 100%. The high performance PDP with Xe: 100% can be operated at low applied voltage between 230 and 377 V due to the high secondary electron emission from the SrCaO cathode. Emission measurements clearly show the change in discharge characteristics at Xe: 30%, where the discharge changes from a Ne/Xe mixture discharge to an almost pure Xe discharge, and the vacuum ultraviolet (VUV) radiation from the combination of resonance and excimer radiations to only excimer radiation. Theoretical analysis solving Boltzmann equation for electron demonstrates that increasing Xe-concentration enhances the collision frequency for electron impact excitation directly from ground state to lower levels concerned with the VUV radiation, resulting in a drastic increase in luminous efficacy up to Xe: 30%. Also, one-dimensional fluid simulation of a Ne/Xe dielectric barrier discharge clearly shows that a combination of high secondary electron emission cathode and high Xe-concentration is quite effective for high VUV radiation efficiency because it induces a drastic increase in electron-heating efficiency. © 2010 American Institute of Physics.

DOI： 10.1063/1.3372612

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出版者・発行元：Digest of Technical Papers SID International Symposium  

The discharge characteristics of PDPs with the protective layers of MgO based ternary oxides are investigated. The panels with a gas mixture of Ne-Xe20% are manufactured by "all-in-vacuum" process, in which the front panels are processed without an exposure to ambient air after the deposition of protective layer. Compared with PDPs with conventional MgO protective layer, a discharge voltage is lowered by 40V and a discharge time lag is shortened within 1 μs. © 2010 SID.

DOI： 10.1889/1.3500576

Scopus

担当区分：筆頭著者   記述言語：英語   出版者・発行元：一般社団法人 日本MRS  

We present the measurement on SrO- and SrCaO-cathode PDP operated at lower voltage. SrO- and SrCaO-cathode PDP attain high luminous efficacy at low voltage, where the breakdown voltage is 30% lower than that of the ordinal MgO-cathode PDP. Emission measurements clearly demonstrate that the SrO- and SrCaO-cathode PDP have a weak discharge with small current flow and low electron energy, which is appropriate for high luminous efficacy of PDP. Also, the direct measurement of VUV radiation from a PDP small cell shows that increasing Xe gas pressure leads to a drastic increase in excimer radiation (172 nm) from Xe molecule, which also considerably contributes to the high luminous efficacy of PDP.

DOI： 10.14723/tmrsj.35.575

CiNii Research

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

We present here analysis of electron energy of a micro dielectric barrier discharge (micro-DBD) for alternating-current plasma display panel (ac-PDP) with Ne/Xe gas mixture by using the optical emission spectroscopy (OES). The OES method is quite useful to evaluate a variety of electron energy in a high pressure DBD ignited in a PDP small cell. Experiment shows that the ratio of Ne emission intensity (I<inf>Ne</inf>) relative to Xe emission intensity (I <inf>Xe</inf>) drastically decreases with time. This temporal profile is well consistent with dynamic behavior of electron temperature in a micro-DBD, calculated in one-dimensional fluid model. I<inf>Ne</inf>/I<inf>Xe</inf> also decreases with an increase in Xe gas pressure and a decrease in applied voltage especially in the initial stage of discharge, and these reflect the basic features of electron temperature in a micro-DBD. The influences of plasma parameters such as electron temperature on luminous efficacy are also theoretically analyzed using one-dimensional fluid model. The low electron temperature, which is attained at high Xe gas pressure, realizes the efficient Xe excitation for vacuum ultraviolet radiation. The high Xe-pressure condition also induces the rapid growth of discharge and consequent high plasma density, resulting in high electron heating efficiency. © 2010 American Institute of Physics.

DOI： 10.1063/1.3291123

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Conference Record of the IEEE Photovoltaic Specialists Conference  

We have deposited cluster-free P-doped a-Si:H films using SiH <inf>4</inf>+PH<inf>3</inf> multi-hollow discharge plasma CVD method. We have measured dependence of a deposition rate and SiH emission intensity on a gas flow rate ratio R=[PH<inf>3</inf>]/[SiH<inf>4</inf>]. The increase of deposition rate with R is much larger than that of SiH emission intensity. These results suggest PH<inf>x</inf> radicals enhance surface reaction probability of SiH <inf>3</inf> radicals. The P concentration in the films can be controlled by the gas flow rate ratio for R<5%. We have succeeded in depositing P-doped a-Si:H films of a low stabilized defect density of 2.9×10¹⁵ cm ^-3. The conductivity of the films is lower than that of the conventional films. Other optoelectronic properties such as conductivity, its activation energy, and bandgap energy are value ranges of the conventional films. © 2010 IEEE.

DOI： 10.1109/PVSC.2010.5616514

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE Region 10 Annual International Conference Proceedings TENCON  

We have deposited cluster-free B-doped a-Si:H films using a SiH <inf>4</inf>=B<inf>10</inf>H<inf>14</inf> multi-hollow discharge plasma CVD method. We have studied gas flow rate ratio R=[B<inf>10</inf>H <inf>14</inf>]/[SiH<inf>4</inf>] dependence of deposition rate and absorbance of films together with plasma emission intensities. Deposition rate increases sharply from 0.8nm/s R=0.0 % to 2.2nm/s for R=0.53%, but SiH emission intensity is almost constant for R=0-2.0%. These results suggest B<inf>x</inf>H <inf>y</inf> radicals enhance surface reaction probability of SiH<inf>3</inf> radicals. The optical bandgap of films is around 1.9eV, being larger than that of conventional B-doped films. © 2010 IEEE.

DOI： 10.1109/TENCON.2010.5686686

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：48th Annual SID Symposium Seminar and Exhibition 2010 Display Week 2010  

The discharge characteristics of PDPs with the protective layers of MgO based ternary oxides are investigated. The panels with a gas mixture of Ne-Xe20% are manufactured by "all-in-vacuum" process, in which the front panels are processed without an exposure to ambient air after the deposition of protective layer. Compared with PDPs with conventional MgO protective layer, a discharge voltage is lowered by 40V and a discharge time lag is shortened within 1 μs.

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE Region 10 Annual International Conference Proceedings TENCON  

We have studied deposition profiles of micro crystalline silicon (μc-Si) films using a multi-hollow discharge plasma CVD method, by which contribution of SiH<inf>3</inf> and H to deposition varies with the distance between the substrate and discharge region. Under high pressure (6 Torr) depletion condition, crystalline films were deposited in a region near the discharges and the higher crystallinity was obtained at the closer to the discharges. Films of 0.6 in crystallinity Φ<inf>C</inf> were deposited in a very narrow region between 4 and 5 mm from the discharges. The process window of good quality μc-Si films is very narrow. These results indicate the multi-hollow discharge plasma CVD method allows us to optimize deposition conditions easier than the conventional deposition methods.

DOI： 10.1109/TENCON.2010.5686679

Web of Science

Scopus

記述言語：英語   出版者・発行元：IEEE Region 10 Annual International Conference Proceedings TENCON  

We present detailed measurements on breakdown voltage (V<inf>f</inf>) in a RF discharge with Si(CH<inf>3</inf>)<inf>2</inf>(OCH<inf>3</inf>)<inf>2</inf> gas diluted with Ar. When Ar concentration (P<inf>Ar</inf>) is increased, the V<inf>f</inf> gradually decreases up to P<inf>Ar</inf> = 50 %, and then is followed by a drastic decrease. The P<inf>Ar</inf> dependence of V<inf>f</inf> is well explained by a feature of the ion-induced secondary electron emission coefficient (γ) deduced from measured Paschen curves. A drastic increase in Ar ion flux with P<inf>Ar</inf> induces high emission of electrons from cathode surface, resulting in lowing V<inf>f</inf>. © 2010 IEEE.

DOI： 10.1109/TENCON.2010.5686704

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE Region 10 Annual International Conference Proceedings TENCON  

We have first conformed the effects of amplitude modulation (AM) of rf discharge voltage on growth of nano-particles in plasma CVD. This method of AM was used to control fluctuation level of plasma parameters, and allow us to investigate the causal relationship between the nano-particle property and plasma fluctuations. We found the ratio of power of single mode to that harmonic mode is negligible small until fluctuation level of amplitude modulated rf peak-to-peak voltage becomes roughly 20 %. The growth of nano-particles during rf discharge decreased as induced plasma fluctuation level increases. © 2010 IEEE.

DOI： 10.1109/TENCON.2010.5686456

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE Region 10 Annual International Conference Proceedings TENCON  

Recent progress in nano-materials has made them attractive for an increasing number of their applications such as electronics, medical components, fillers, catalysts, and fuel cells. Nanomaterials need structures and components which exhibit novel and significantly improved physical, chemical and biological properties, because of their nanoscale size, and hence fabrication of nanomaterials by bottom-up processes as well as that by top-down ones are required. A wide variety of nano-material and nano-system fabrication methods are required to be developed to realize complex nano-world. Plasma-based fabrication of nanomaterials and nanostructures is widely employed for top-down processes such as ULSI fabrication as well as bottom-up processes such as carbon nanotube production. We are exploring frontier science of interactions between plasmas and nano-interfaces by focusing on novel features such as fluctuations of interactions due to the nanometer scale. Plasma processing based on the science realizes highly precise top-down processes by suppressing fluctuations and well controlled self-organized bottom-up processes by controlling fluctuations. We aim to bring about an explosive development of fabrication technologies of nanomaterials and nanostructures. ©2010 IEEE.

DOI： 10.1109/TENCON.2010.5685920

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：IEEE Region 10 Annual International Conference Proceedings TENCON  

We have measured photoluminescence spectra of crystalline and amorphous Si nanoparticles dispersed in methanol to demonstrate exciton generation under 244nm and 405nm laser light excitation. The photoluminescence spectra have broad peaks centered at 484-500nm, indicating exciton generation in crystalline and amorphous Si nanoparticles. In addition, the peaks corresponding to the recombination centers at their surface defects are observed at 324nm-380nm. This indicates the importance of termination of surface defects on nanoparticles for application to solar cells. © 2010 IEEE.

DOI： 10.1109/TENCON.2010.5686677

Web of Science

Scopus

出版者・発行元：IEEE Region 10 Annual International Conference Proceedings TENCON  

We have investigated growth stimulation of radish sprouts using nonthermal atmospheric pressure He discharge plasmas and low pressure O<inf>2</inf> RF discharge plasmas. Seeds of radish sprouts were irradiated by one of these plasmas. After 7 days cultivation, the average length of sprouts with irradiation was 15-60 % longer than those without irradiation. Reactive oxygen species may be involved in the growth stimulation mechanism. © 2010 IEEE.

DOI： 10.1109/TENCON.2010.5686474

Web of Science

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Conference Record of the IEEE Photovoltaic Specialists Conference  

We have fabricated Si quantum dot-sensitized solar cells by three assembling methods; the conventional method and two novel methods in which Si nanoparticles/TiO<inf>2</inf> blend paste is coated onto FTO glass, or TiO <inf>2</inf> film. The highest current density is realized s solar cell for which Si nanoparticles/TiO<inf>2</inf> blend paste is coated onto TiO <inf>2</inf> films. The result indicates that excitons generated in Si nanoparticles are separated into electrons and holes and such carriers are extracted to the outer circuit. Photon-to-current conversion efficiency (PCE) of our Si quantum dot-sensitized solar cells is larger than that of the cell without Si nanoparticles in a wavelength range below 500nm. It suggests that carrier generation in the Si nanoparticles is realized in the wavelength range less than 500 nm in the solar cell. Light intensity dependence of photo-current density shows superliner one for photon energy larger than twice of the bandgap energy of the Si nanoparticles. © 2010 IEEE.

DOI： 10.1109/PVSC.2010.5617205

Web of Science

Scopus

出版者・発行元：Idw 09 Proceedings of the 16th International Display Workshops  

The PDPs with high γ protective layer consisting of SrCaO are perfectly manufactured by using the "all-in-vacuum" process without exposing a protecting layer to ambient air. The SrCaO panel with Ne/Xe(20%) shows 2.3 times larger luminous and 1.7 times larger luminous efficacy compared with that of MgO panel with Ne/Xe(4%), where two panels have almost same breakdown voltage. The SrCaO-PDP(Xe:20%) also shows the almost same discharge time-lag with MgO-PDP(4%), which means that high performance SrCaO-PDP manufactured by our "all-in-vacuum"process can be operated using conventional driving wave-form for MgO-PDP.

Scopus

出版者・発行元：Idw 09 Proceedings of the 16th International Display Workshops  

The PDPs with high γ protective layer consisting of SrCaO are perfectly manufactured by using the "all-in-vacuum" process without exposing a protecting layer to ambient air. The SrCaO panel with Ne/Xe(20%) shows 2.3 times larger luminous and 1.7 times larger luminous efficacy compared with that of MgO panel with Ne/Xe(4%), where two panels have almost same breakdown voltage. The SrCaO-PDP(Xe:20%) also shows the almost same discharge time-lag with MgO-PDP(4%), which means that high performance SrCaO-PDP manufactured by our "all-in-vacuum"process can be operated using conventional driving wave-form for MgO-PDP.

Scopus

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

We present here measurements of plasma display panel (PDP) ignited by SrO and SrCaO cold cathodes with high yield of ion-induced secondary electron emission (high γ<inf>i</inf>). SrO- and SrCaO-cathode PDPs attain high luminous efficacy at low applied voltage, where the breakdown voltage is 30% lower than that of ordinary MgO-cathode PDP. Current and emission measurement clearly demonstrates that SrO- and SrCaO-cathode PDPs operated at low voltage realize a discharge with smaller current flow and lower electron energy, which are considerably appropriate for high luminous efficacy of PDP. Simulation analysis shows the effect of the high- γ<inf>i</inf> cathode on the luminous efficacy of PDP. A discharge ignited by the high- γ<inf>i</inf> cathode realizes high electron heating efficiency due to the abundant seed electrons from the high- γ<inf>i</inf> cathode, resulting in high luminous efficacy of PDP. © 2009 American Institute of Physics.

DOI： 10.1063/1.3253723

Web of Science

Scopus

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Journal of Applied Physics  

We present the influence of gas pressure and applied voltage on Xe excimer radiation from a microdielectric barrier discharge (micro-DBD) in Ne/Xe gas mixture for plasma display panel. Measurements show that the excimer radiation with the 172 nm band lines is strongly observed in the afterglow, and drastically increases with an increase in gas pressure and applied voltage. It is also found that for high gas pressure and low voltage, excimer molecule (Xe<inf>2</inf>^z.ast;) is efficiently produced because of less infrared emission from Xe excited atom. The reaction processes of Xe metastable atom (Xe<inf>1s5</inf>^z.ast; ), which is a precursor for Xe <inf>2</inf>^z.ast;, are theoretically analyzed using a one-dimensional fluid model. Increasing gas pressure results in large excimer radiation due to the enhancement of the following three processes, i.e., the conversion process from Xe<inf>1s5</inf>^z.ast; to Xe<inf>2</inf> ^z.ast;, the direct electron impact excitation from ground state to Xe<inf>1s5</inf>^z.ast; , and the collisional de-excitation process from upper level (Xe^*) to Xe<inf>1s5</inf>^z.ast; . The simulation analytical result shows that for lower voltage, Xe <inf>1s5</inf>^z.ast; is efficiently produced due to the increase in the ratio of direct excitation to Xe<inf>1s5</inf>^z.ast; from ground state and the suppression of the stepwise ionization from Xe<inf>1s5</inf> ^z.ast; by electron collisions. While for high voltage operation of micro-DBD, the recombination process with Xe molecular ion (Xe<inf>2</inf> ⁺) and electron contributes to the total excimer radiation, which can be responsible for the large excimer radiation observed in experiment. © 2009 American Institute of Physics.

DOI： 10.1063/1.3236508

Web of Science

Scopus

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physics of Plasmas  

The Coulomb crystal of strongly coupled fine particles is formed by electron shower in a direct current discharge plasma, where the electron shower is injected from an auxiliary plasma which is situated below a main plasma. In case of electron shower injection, the phase transition of dust particles is controlled under the constant argon pressure. The characteristic properties of electron shower injection are discussed theoretically by using a simple collisional sheath model. The calculation analysis clearly shows that electron injection causes the change in charges on fine particles, resulting in a liquid-solid phase transition as in the experiment. © 2009 American Institute of Physics.

DOI： 10.1063/1.3205879

Web of Science

Scopus

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physics of Plasmas  

The two-dimensional dust vortex flows are observed in a direct current discharge plasma near the edge of a metal plate which is situated in the dust-particle levitation region. Applying negative dc potential to the metal plate, dust particles are strongly accelerated toward the metal plate edge, and two symmetric dust vortex flows are generated on both sides of the metal plate. Numerical calculation including the effect of the ion drag force well demonstrates the dust vortex formation as in the experiment. A mechanism of the dust vortex generation could be explained by effect of an asymmetry of ion drag force near the metal plate. © 2009 American Institute of Physics.

DOI： 10.1063/1.3139252

Web of Science

Scopus

出版者・発行元：Idw 08 Proceedings of the 15th International Display Workshops  

A cathode luminescence spectroscopy is applied to discuss the electronic properties of MgO. The measurements at various temperatures below 300 K suggest that the UV luminescence peaked at 240 nm is due to the exciton formation.

Scopus

出版者・発行元：Idw 08 Proceedings of the 15th International Display Workshops  

A cathode luminescence spectroscopy is applied to discuss the electronic properties of SrO thin film. The measurements at various temperatures below 300 K suggest that the UV luminescence peaked at 245 nm is due to the exciton formation.

Scopus

出版者・発行元：Idw 08 Proceedings of the 15th International Display Workshops  

We study experimentally AC-PDP with the narrow sustaining electrode (W <inf>ITO</inf>) in high Xe contents. The specialized-PDP with narrow W <inf>ITO</inf> achieves high luminous efficacy. The VUV measurement also shows that narrow W<inf>ITO</inf> leads to the strong excimer radiation.

Scopus

出版者・発行元：Idw 08 Proceedings of the 15th International Display Workshops  

Plasma display panels are manufactured in a vacuum condition. As a protecting layer, MgO, CaO, SrO and SrCaO with various compositions are used. It is demonstrated that the panels processed in vacuum shows a lower discharge voltages and higher luminous efficacy compared with the conventional ones.

Scopus

出版者・発行元：Idw 08 Proceedings of the 15th International Display Workshops  

Here is presented the measurement on SrO- and SrCaO-PDP operated at lower voltage. SrO- and SrCaO-PDP attained high luminous efficacy at low voltage, where the breakdown voltage is 30 % lower than that of the ordinary MgO-PDP. Direct observation of vacuum ultraviolet radiation also shows that the excimer production is more efficient for high Xe contents and high sustaining voltage.

Scopus

出版者・発行元：Idw 08 Proceedings of the 15th International Display Workshops  

A PDP manufacturing method suitable for energy and cost savings is demonstrated. In the method, the panel processing after MgO deposition and panel sealing are all completed under a controlled vacuum circumstance. As a result, the shorter aging time for stable discharge and the lower firing voltage is successfully achieved.

Scopus

出版者・発行元：SID Conference Record of the International Display Research Conference  

For plasma display panels (PDPs), the performance of protective layers is extremely important, since it determines VUV generation efficacy and discharge time-lag. The performance of protective layers has been evaluated mainly by two kinds of physical quantity: secondary electron emission coefficient (γ) and mean free path (λ) of conduction electrons. This paper discusses how the protective layer with higher y affects the discharge dynamics of micro-plasma in PDPs. © 2008 SID.

Scopus

出版者・発行元：Idw 08 Proceedings of the 15th International Display Workshops  

The temperature dependence of photoluminescence spectroscopy and thermoluminescence property on BAM:Eu and SAM.Eu are investigated. Peak shift of PL spectroscopy on SAM.Eu is largely observed between 50 and 300 K compared with BAM:Eu. The TL results reveal that the states of europium occupied in BAM and SAM should be different.

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）   出版者・発行元：Proceedings of International Meeting on Information Display  

Hiroshima University opened the advanced display laboratory (ADL) in 2006 to specifically focus on the PDP researches. The mission of ADL is to lay the bases for the innovative PDP technologies. Our research efforts have been concentrated on the fundamental study of protective materials and phosphors, and also of the effect of protective materials with high y emission in the high luminous efficacy. This paper briefly introduces the present status of our research activities.

Scopus

記述言語：日本語   出版者・発行元：一般社団法人 映像情報メディア学会  

交流型プラズマディスプレイパネル(AC-PDP)の保護膜材料としてSrOを用い,そのPDPの特性評価を行った.PDPの駆動に重要なパネル点灯電圧(放電開始電庄)が従来のMgO保護膜PDPの約70%の値と大幅に低減し,発光効率はXeガス混合比4%の条件において,1.5倍と大きく上昇した.またMgO並びにSrO保護膜PDPの発光分光計測を詳細に行い,プラズマパラメータの変化の様子を解析した.低電圧で駆動されるSrO保護膜PDPは,Ne原子からの発光が極めて弱く,プラズマ中の電子エネルギー状態がMgOパネルに比べ低いことが確認された.本研究においてPDPの低電圧化は,発光効率に大きく貢献することが明らかになった.

DOI： 10.11485/itetr.32.31.0_37

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人 映像情報メディア学会  

Xe^+による二次電子放出係数γ(Xe)を有するMgOベースの保護膜材料を合成し、AC-PDPにおける放電開始電圧に及ぼす効果について測定した.測定の結果、0.01オーダーの僅かなγ(Xe)の増加が放電開始電圧を減少させ、Xe成分が高くなるにつれてその効果が大きくなることが判明した。

DOI： 10.11485/itetr.32.31.0_41

CiNii Research

出版者・発行元：Idw 07 Proceedings of the 14th International Display Workshops  

Here is presented direct observation of vacuum ultraviolet radiation from alternating-current plasma display (AC-PDP) with Ne/Xe gas mixtures. Measurement shows that high ultraviolet-radiation efficiency is attained especially for high Xe contents. The change of electron energy is also analyzed from Ne and Xe emission spectra. There is considerable effect of Xe contents on electron energy. Our experiment shows that electron energy directly affects the ultraviolet-radiation efficiency.

Scopus

出版者・発行元：Idw 07 Proceedings of the 14th International Display Workshops  

MgO based protective layers with finite secondary electron emission coefficient by Xe⁺, γ<inf>(Xe)</inf>, are synthesized and their effect on firing voltage is measured in AC-PDPs. It is measured that the slight increase of γ<inf>(Xe)</inf> by an order of 0.01 reduces the firing voltage and that the reduction becomes larger at higher Xe content.

Scopus

出版者・発行元：Idw 07 Proceedings of the 14th International Display Workshops  

The suppression of plasma degradation of RGB phosphors is tried using hydrogen plasma treatment. It is shown that BAM:Eu²⁺(B)and Zn <inf>2</inf>SiO<inf>4</inf>:Mn²⁺ (G) gets higher resistance against for Ne+Xe plasma irradiation, while the lifetime of (Y, Gd)BO <inf>3</inf>:Eu³⁺ (R) is unchanged by hydrogen plasma treatment.

Scopus

出版者・発行元：Idw 07 Proceedings of the 14th International Display Workshops  

Photoemissions induced by Auger reaction between incident inert ions and MgO surface are measured. It is shown that the midgap states such as F-type centers could be observed.

Scopus

出版者・発行元：AD 07 Proceedings of Asia Display 2007  

The role of oxygen vacancy in undoped and Eu-doped BaMgAl <inf>10</inf>O<inf>17</inf> (BAM) phosphors has been investigated under vacuum ultraviolet (VUV) excitation. From the results of photolumiescence (PL) and thermoluminescence (TL), it is found that the host emission from BAM is relative to oxygen vacancy which induces electron traps in BAM. According to the change of PL and TL characteristics in the undoped and Eu-doped BAM, we propose a model to explain the radiative and non-radiative energy trasfer processes in BAM: Eu²⁺ under VUV excitation.

Scopus

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

Web of Science

出版者・発行元：Idw 06 Proceedings of the 13th International Display Workshops  

The degradation processes induced by baking and plasma irradiation in undoped and Eu-doped BAM (BaMgAl<inf>10</inf>O<inf>17</inf>) are investigated by photoluminescence (PL) and thermoluminescence (TL) spectroscopy. The PL and TL spectra of undoped BAM change little in baking process. The TL spectra of Eu-doped BAM indicates that the baking process shakes down the number density of original electron traps, whereas a deep electron trap is newly formed at 300 K. As for a plasma irradiation, it has severe effect on the original electron traps in BAM host but only a slight effect on Eu-doped BAM. Thus the degradation processes induced by baking and plasma irradiation are quite different and they depend on the oxidation of Eu²⁺ and the stability of BAM host.

Scopus

出版者・発行元：Idw 06 Proceedings of the 13th International Display Workshops  

A new PDP manufacturing method in which processes, such as deposition of MgO, and sealing of front and rear plate, are carried out in succession under the vacuum condition is proposed. During the process, MgO surface is expected to be kept clean. We have evaluated the firing voltage by using a 4-inch PDP test panel. The measured result shows that the firing voltage is stabilized in a brief time from the beginning of the measurement. The developed method is considerably effective for decreasing the aging process time.

Scopus

出版者・発行元：Idw 06 Proceedings of the 13th International Display Workshops  

A significant secondary electron emission, SEE, by Xe⁺ was observed for 12CaO-7AI<inf>2</inf>O<inf>3</inf> crystals with 'F ⁺-like center' concentration, N, of 10¹⁹ to 10 ²¹ cm^-3 (so-called C12A7 electride) prepared using aluminum or carbon as reducing reagents. The SEE yield by Xe⁺ was increased with increasing N and reached -0.2 at N=10²¹ cm ³, which may be attributed to F⁺-like center inherent to C12A7 electride, that gives a small work function of 0.6-2.1 eV to the present material.

Scopus

出版者・発行元：Idw 06 Proceedings of the 13th International Display Workshops  

Temperature dependence of photoluminescence (PL) and thermoluminescence (TL) are measured on BaMgAI<inf>10</inf>O<inf>17</inf> (BAM) between 50 and 500 K. The exciton emission peak shifts from 270 to 242 nm and its intensity increases significantly, as the sample temperature decreases. The TL measurement supports the idea that the oxygen vacancies in BAM affect the exciton emission properties. Based on the results, the electron transport mechanism before exciton formation is proposed, in which electrons have undergone a non-radiative transition and this frequent is depending on the temperature.

Scopus

出版者・発行元：Idw 06 Proceedings of the 13th International Display Workshops  

Here is presented experiment on temporal evolution and spatial distribution of optical emission spectra from alternating-current plasma display panel (AC-PDP). Measurement shows that the relative emission intensity (I <inf>Ne(585nm)</inf>/I<inf>Xe(823nm)</inf>) which is induced from Ne and Xe atom, drastically changes in each discharge stage and each spatial region. In initial discharge, Intensity of Ne emission (I<inf>Ne(585nm)</inf>) is much stronger than that of Xe emission (I<inf>Xe(823nm)</inf>) in cathode and anode region, and I<inf>Ne(585nm)</inf>/I<inf>Xe(823nm)</inf> decreases with an increase in discharge time (t<inf>d</inf>). There is also considerable effect of discharge voltage (V<inf>s</inf>) and gas pressure (P<inf>Ne/Xe</inf>) on I<inf>Ne(585nm)</inf>/I<inf>Xe(823nm)</inf>. The time-resolved measurement of optical emission spectra is useful to investigate the electron temperature (T<inf>e</inf>) in PDP.

Scopus

出版者・発行元：Idw AD 05 Proceedings of the 12th International Display Workshops in Conjunction with Asia Display 2005  

Secondary electron emission coefficient, γ, of MgO deposited on a metal substrate was measured at the temperatures below and above the deposition temperatures. The γ was temperature dependent and had a broad convex peak at the temperature a little bit higher than the deposition temperature. The mechanism of temperature dependence of γ is discussed based on the thermal stress induced by the mismatch of thermal expansion coefficient between an MgO film and a metal substrate.

Scopus

出版者・発行元：Idw AD 05 Proceedings of the 12th International Display Workshops in Conjunction with Asia Display 2005  

Secondary electron emission (SEE) from MgO is measured at the temperatures between 373 and 673 K. The sample is the one deposited at 523 K on indium tin oxide (ITO) coated glass substrate. We find that there are three SEE phases depending on the temperatures: low emission phase above 573 K, high emission phase below 423 K and transition phase at intermediate temperatures.

Scopus

出版者・発行元：IEEE International Conference on Plasma Science  

Micro particles that are introduced into a plasma environment charge up to a high negative value due to ion and electron bombardment. As a result of the strong Coulomb interaction?between the particles often so-called "plasma crystals" are built up. These systems show a variety of wave phenomena like dust acoustic waves, dust shear waves, etc. that have been investigated partially only. In this paper, the wave dispersion relation is analyzed in a two-dimensional plasma crystal under magnetic field influence by theoretical analysis and molecular dynamics simulation. An expression for the wave dispersion relation clearly shows that the longitudinal and the transverse modes in a plasma crystal are coupled due to the Lorenz force acting on dust particles. The dispersion relation has a high- and a low- frequency branch. Our analysis shows that the high-frequency branch has a cut-off at the cyclotron frequency of the dust particles, and the wave polarization drastically changes with magnetic field strength. In this presentation, we also report on the experimental results of the wave propagation in a magnetized dusty plasma.

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physical Review Letters  

The wave dispersion relation in a two-dimensional plasma crystal under magnetic field influence was derived. The wave spectrum due to thermal motion of the dust particles in a simulated plasma crystal was analyzed and compared to theoretical prediction. The expression for the wave dispersion relation shows that high-frequency and low-frequency branches exist as a result of the coupling of longitudinal and transverse modes due to the Lorentz force acting on the dust particles. The results show that the high-frequency and the low-frequency branches are found to belong to right-hand and left-hand polarized waves, respectively.

DOI： 10.1103/PhysRevLett.93.155002

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Thin Solid Films  

To suppress inclusion of fine particles in amorphous silicon films, a negatively-charged fine particle (NFP) collector has been successfully installed in a silane plasma. Two modes of operation of the NFP collector biasing were examined: (i) turning on after the appearance of fine particles; and (ii) turning on from the very beginning of the plasma operation. While the former proved the effectiveness of the NFP collector in the removal of fine particles, apparently very small particles (<100 nm) removal in the latter reduced the degradation of the photo conductivity in deposited a-Si:H films by light soaking. This effect is accompanied by the increased density of Si-H bonding, which can be related to the possible modification in the silicon networks in the amorphous film. © 2003 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.tsf.2003.11.300

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Physics of Plasmas  

DOI： 10.1063/1.1342229

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：IEEE Transactions on Plasma Science  

The spatial shape of fine-particle clouds in a strongly coupled state is controlled by varying a radial potential profile provided by radially segmented electrode for particle levitation and confinement under a completely dc configuration. Fine-particle clouds change their shapes from a usual two-dimensional disk to a three-dimensional cone, and finally concave cone with an increase in the radial potential slope. These profiles are closely related to an axial variation of the radial potential profile in the ion sheath above the segmented electrode. When we apply to the segmented electrode a potential profile with peaks between the radial center and edge, fine particles are rearranged to form azimuthal rings on the horizontal plane. The radial width of the rings is controlled by changing the peak width of the radial potential profile.

DOI： 10.1109/27.923707

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

記述言語：日本語   出版者・発行元：一般社団法人 日本物理学会  

DOI： 10.11316/jpsgaiyo.55.1.2.0_153_2

Open Access

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1016/B978-044450398-5/50071-3

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1016/B978-044450398-5/50044-0

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1016/B978-044450398-5/50070-1

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

DOI： 10.1016/B978-044450398-5/50072-5

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DOI： 10.1006/bbrc.1999.0444

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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記述言語：英語   掲載種別：研究論文（国際会議プロシーディングス）  

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DOI： 10.1006/bbrc.1995.2399

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DOI： 10.1016/0378-4347(94)00524-9

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記述言語：日本語  

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記述言語：英語   出版者・発行元：大阪大学接合科学研究所  

We present here analysis of the discharge characteristics of a non-thermal plasma jet, where the surrounding gas condition of the plasma jet is precisely controlled in open air. The mixing of the surrounding gas into the plasma jet markedly changes the discharge characteristics: the optical emission intensity of Ni2+ linearly increases with an increase in gas flow ratio of N2 to O2 in the surrounding gas. Our experiments clearly demonstrate that the plasm jet could be controlled from O2 main discharge to N2 main discharge by changing the surrounding gas condition even in open air.

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記述言語：英語   掲載種別：研究発表ペーパー・要旨（全国大会，その他学術会議）  

DOI： 10.7566/JPSCP.1.015072

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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出版者・発行元：Materials Science Forum  

We report characteristics of quantum dot (QD) sensitized solar cells using Si nanoparticles and Ge nanoparticles. Si nanoparticles were synthesized by multi-hollow discharge plasma chemical vapor deposition, whereas Ge nanoparticles were done by a radio frequency magnetron sputtering using Ar+H2 under high pressure conditions. The electrical power generation from Si QDs and Ge QDs was confirmed. Si QD sensitized solar cells show an efficiency of 0.024%, fill factor of 0.32, short-circuit current of 0.75 mA/cm² and open-circuit voltage of 0.10 V, while Ge QD sensitized solar cells show an efficiency of 0.036%, fill factor of 0.38, short-circuit current of 0.64 mA/cm2 and open-circuit voltage of 0.15 V. © (2014) Trans Tech Publications, Switzerland.

DOI： 10.4028/www.scientific.net/MSF.783-786.2022

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記述言語：英語   出版者・発行元：Materials Research Society Symposium Proceedings  

We present here performance of Li ion batteries with SiC nanoparticle-film anode, which is fabricated by a double multi-hollow discharge plasma chemical vapor deposition (CVD) method. The first cycle of charge/discharge property of the Li ion battery with the SiC nanoparticle-film anode shows a high capacity of over 4,000 mAh/g, which is 12 times higher than the Li ion battery with the conventional graphite anode. The discharge capacity shows high stability for first 10th cycle, and is 3750 mAh/g for the 10th cycle.

DOI： 10.1557/opl.2014.742

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）  

DOI： 10.7567/JJAP.52.01AB01

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記述言語：英語   出版者・発行元：Materials Research Society Symposium Proceedings  

We have developed a cluster-eliminating filter which reduces amount of amorphous silicon nanoparticles (clusters) incorporated into a-Si:H films. We have applied the filter to fabricate a-Si:H Schottky solar cells. The cells show a high initial fill factor FF=0.563 and a high stabilized value after light soaking FF=0.552 which light-induced degradation was quite low value of 1.95%. © 2012 Materials Research Society.

DOI： 10.1557/opl.2012.1245

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記述言語：英語   出版者・発行元：Materials Research Society Symposium Proceedings  

Quantum dot-sensitized solar cells (QDSCs) based on the multiple exciton generation (MEG) of QD are attractive in the field of photochemical cells because the improvement of conventional sensitized solar cells has been stagnant recently. The distinctive characteristics of QDs are their strong photo-response in the visible region and quantum confinement effects. Its theoretical efficiency is much higher than that of solar cell based on the single exciton generation (SEG). Moreover, QDs have tunable optical properties and band-gaps depending on the particle size. But QD materials widely used for QDSC have some disadvantages of toxicity and scarcity. On the other hand, Si as one of good QD materials is abundant and not toxic. Also, Si QD has high stability against light soaking and a high optical absorption coefficient due to quantum size effects. However, the research on Si QD is rare although the quantum effect of Si was already verified. It is one of reasons that the fabrication and collection of Si nano-particles are too difficult. Therefore, this work proposed multi-hollow plasma discharge chemical vapor deposition (CVD). It is possible to collect Si particles unlike conventional CVD and solve the problems of the wet process. The optical properties of Si particles were controlled by varying experimental conditions. In this work, Si particles were fabricated with various sizes and their characteristics were analyzed. Based on the results, Si QD was applied to Si QDSC. © 2012 Materials Research Society.

DOI： 10.1557/opl.2012.890

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記述言語：英語   出版者・発行元：Materials Research Society Symposium Proceedings  

We have carried out in-situ measurements of cluster volume fraction in silicon films during deposition by using quartz crystal microbalances (QCM's) together with a cluster-eliminating filter. The cluster volume fraction in films is deduced from in-situ measurements of film deposition rates with and without silicon clusters using QCM's. The resulls show that the higher deposition rate leads to the higher volume fraction of clusters. © 2012 Materials Research Society.

DOI： 10.1557/opl.2012.839

Scopus

記述言語：英語   掲載種別：研究発表ペーパー・要旨（全国大会，その他学術会議）  

記述言語：英語   掲載種別：速報，短報，研究ノート等（学術雑誌）  

記述言語：英語   掲載種別：研究発表ペーパー・要旨（全国大会，その他学術会議）  

記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

反応性プラズマを用いるプラズマプロセスでは,気相中で微粒子が発生することが多い.近年,この微粒子を多階層のナノシステムの機能性ナノ部品として使用するボトムアップ型のナノテクノロジーへの展開が盛んに行われている.本章では,この展開に重要な部分帯電した微粒子群の凝集と輸送についての最近の研究成果を紹介する.

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その他リンク： http://dl.ndl.go.jp/info:ndljp/pid/10458058

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記述言語：日本語   出版者・発行元：化学工業社  

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記述言語：日本語   出版者・発行元：テクノタイムズ社  

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

交流型プラズマディスプレイパネル(AC-PDP)の微細セル中で発生するNe/Xe放電からの発光スペクトルを高時間分解で詳細に計測した.放電初期においては比較的高エネルギーの電子で励起されるNe原子からの発光が,また放電後半から終盤にかけては低エネルギー電子で励起されるXe原子からの発光が相対的に強く観測された.このようなPDP放電からの発光特性は,プラズマ中の電子エネルギーの推移を表しており,PDPの発光効率と密接に関係していることが明らかになった.本研究で行った時分割分光計測はPDPの電子エネルギー状態の解析に極めて有効である.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

BaMgAl_<10>O_<17>(BAM)およびSrMgAl_<10>O_<17>(SAM)について真空紫外線励起下での発光、熱ルミネッセンス特性を調べた。室温においてBAMの場合には母体発光が観察されたが、SAMの場合には母体発光は認められなかった。この結果からBAMの母体発光は結晶格子中の欠陥に関連していることが示唆された。また、この母体発光がEu^<2+>へのエネルギー伝達の一つの経路であるが、146nm励起下ではEu^<2+>発光の約20%に母体発光が寄与しているという計算結果が得られた。

CiNii Research

記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

PDP用青色蛍光体BaMgAl_<10>O_<17>:Eu^<2+>(BAM:Eu^<2+>)のプラズマ処理の効果について検討した。Arをベースとした水素、酸素プラズマで処理した結果、水素プラズマで処理した場合にのみ、BAM:Eu^<2+>蛍光体の寿命が改善した。フォトルミネッセンス、熱ルミネッセンス測定の結果、水素プラズマ処理により劣化に関連する電子トラップが減少していることが明らかとなった。また、フォトルミネッセンスの結果から、BAM結晶中の欠陥が水素結合により修復されていることが示唆された。

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記述言語：日本語   出版者・発行元：映像情報メディア学会  

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記述言語：日本語   出版者・発行元：映像情報メディア学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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DOI： 10.1016/S0925-9635(02)00289-3

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：プラズマ・核融合学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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記述言語：日本語   出版者・発行元：一般社団法人日本物理学会  

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