研究者詳細 - 黒川　康良

論文 - 黒川　康良

分割表示 154 件中 1 - 20 件目／全件表示 >>

Bayesian optimization of hydrogen plasma treatment in silicon quantum dot multilayer and application to solar cells 査読有り国際誌

Fuga Kumagai, Kazuhiro Gotoh, Satoru Miyamoto, Shinya Kato, Kentaro Kutsukake, Noritaka Usami, Yasuyoshi Kurokawa

Nanoscale Research Letters 18 巻 ( 1 ) 頁： 43 2023年3月

Thermoelectric properties of Mg2Si thin films prepared by thermal evaporation of Mg and face-to-face annealing 査読有り国際誌

Y. Kurokawa, K. Sato, K. Shibata, S. Kato, S. Miyamoto, K. Gotoh, T. Itoh, N. Usami

Materials Science in Semiconductor Processing 163 巻頁： 107552 2023年8月

Preparation and thermoelectric characterization of boron-doped Si nanocrystals/silicon oxide multilayers 査読有り国際誌

Keisuke Shibata, Shinya Kato, Masashi Kurosawa, Kazuhiro Gotoh, Satoru Miyamoto, Noritaka Usami, Yasuyoshi Kurokawa

JAPANESE JOURNAL OF APPLIED PHYSICS 62 巻 ( SC ) 頁： SC1074 2023年2月

Application of Bayesian optimization for improved passivation performance in TiOx/SiOy/c-Si heterostructure by hydrogen plasma treatment 査読有り国際誌

APPLIED PHYSICS EXPRESS 14 巻 ( 2 ) 頁： 025503 2021年2月

Preparation and thermoelectric characterization of phosphorus-doped Si nanocrystals/silicon oxide multilayers 査読有り国際誌

Kobayashi Hisayoshi, Akaishi Ryushiro, Kato Shinya, Kurosawa Masashi, Usami Noritaka, Kurokawa Yasuyoshi

JAPANESE JOURNAL OF APPLIED PHYSICS 59 巻 ( SG ) 頁： SGGF09 2020年4月

Effect of the Niobium-Doped Titanium Oxide Thickness and Thermal Oxide Layer for Silicon Quantum Dot Solar Cells as a Dopant-Blocking Layer 査読有り国際誌

Ryushiro Akaishi, Kohei Kitazawa, Kazuhiro Gotoh, Shinya Kato, Noritaka Usami, Yasuyoshi Kurokawa

Nanoscale Research Letters 15 巻 ( 1 ) 頁： 39 2020年

Local Structure of High Performance TiO <inf>x</inf> Electron-Selective Contact Revealed by Electron Energy Loss Spectroscopy 査読有り国際誌

Mochizuki Takeya, Gotoh Kazuhiro, Kurokawa Yasuyoshi, Yamamoto Takahisa, Usami Noritaka

Advanced Materials Interfaces 6 巻 ( 3 ) 頁： 1801645 2019年2月

Bandgap tuning of silicon nanowire arrays for application to all-silicon tandem solar cells 査読有り国際誌

Y. Kurokawa, M. Yano, S. Miyajima, and A. Yamada

Jpn. J. Appl. Phys. 56 巻頁： 04CS03 2017年2月

Photoluminescence from silicon quantum dots in Si quantum dots/amorphous SiC superlattice 査読有り国際誌

Kurokawa Yasuyoshi, Tomita Shigeki, Miyajima Shinsuke, Yamada Akira, Konagai Makoto

JAPANESE JOURNAL OF APPLIED PHYSICS 46 巻 ( 33-35 ) 頁： L833 - L835 2007年9月

Preparation of nanocrystalline silicon in amorphous silicon carbide matrix 査読有り国際誌

Kurokawa Yasuyoshi, Miyajima Shinsuke, Yamada Akira, Konagai Makoto

JAPANESE JOURNAL OF APPLIED PHYSICS 45 巻 ( 37-41 ) 頁： L1064 - L1066 2006年10月

Hydrogenation of silicon-nanocrystals-embedded silicon oxide passivating contacts 査読有り

Matsumi, M; Gotoh, K; Wilde, M; Kurokawa, Y; Fukutani, K; Usami, N

NANOTECHNOLOGY 35 巻 ( 10 ) 2024年3月

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

We investigate the effect of hydrogen passivation of dangling bonds in silicon oxide passivating contacts with embedded silicon nanocrystals (NAnocrystalline Transport path in Ultra-thin dielectrics for REinforced passivation contact, NATURE contact). We first investigated the differences in electrical properties of the samples after hydrogen gas annealing and hydrogen plasma treatment (HPT). The results show that the NATURE contact was efficiently passivated by hydrogen after HPT owing to the introduction of hydrogen radicals into the structure. Furthermore, we examined the dependence of process parameters such as HPT temperature, duration, and H2 pressure, on the electrical properties and hydrogen depth profiles. As a result, HPT at 500 °C, 15 min, and 0.5 Torr resulted in a large amount of hydrogen inside the NATURE contact and the highest implied open-circuit voltage of 724 mV. Contact resistivity and surface roughness hardly increased when HPT was performed under the optimized condition, which only improved the passivation performance without deteriorating the electron transport properties of the NATURE contact.

DOI： 10.1088/1361-6528/ad115d

Web of Science

Scopus

PubMed

Core-shell yarn-structured triboelectric nanogenerator for harvesting both waterdrop and biomechanics energies 査読有り

Wang, HT; Kurokawa, Y; Zhang, JH; Gotoh, K; Liu, X; Miyamoto, S; Usami, N

APPLIED PHYSICS EXPRESS 17 巻 ( 1 ) 2024年1月

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

Wearable energy harvesters (WEHs) have garnered significant attention recently due to their promising capabilities in powering wearable devices. In this research, we present a core-shell yarn-structured triboelectric nanogenerator (CY-TENG) that operates in two modes: the single-electrode TENG (SE-TENG) and the droplet-based electricity generator. This design facilitates energy harvesting from both waterdrops and biomechanics. The CY-TENG is fabricated using fluorinated ethylene propylene ultrafine heat-shrink tubes combined with stainless-steel yarns, ensuring its flexibility, durability, and weavability. Such attributes underscore its potential as a dual-function WEH.

DOI： 10.35848/1882-0786/ad1f06

Web of Science

Scopus

Influence of Insertion Position of a LiF Buffer Layer on Passivation Performance of Crystalline Si/SiOy/TiOx/Al Heterostructures 査読有り国際誌

Shohei Fukaya, Kazuhiro Gotoh, Takuya Matsui, Hitoshi Sai, Yasuyoshi Kurokawa, Noritaka Usami

Proc. 50th IEEE Photovoltaic Specialists Conference 頁： 1 - 3 2023年12月

Numerical Simulation Study for Analysis of Hydrogenated Amorphous Silicon/Crystalline Silicon Heterostructure by Reactive Molecular Dynamics Method 査読有り国際誌

Proc. 50th IEEE Photovoltaic Specialists Conference 頁： 1 - 3 2023年12月

Free-Standing Electrode and Fixed Surface Tiny Electrode Implemented Tiboelectric Nanogenerator with High Instantaneous Current 査読有り

Wang, HT; Kurokawa, Y; Wang, J; Cai, WT; Zhang, JH; Kato, S; Usami, N

SMALL 頁： e2308531 2023年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Small

Conventional triboelectric nanogenerators (TENGs) face challenges pertaining to low output current density at low working frequencies and high internal impedance. While strategies, such as surface modification to enhance surface charge density, permittivity regulation of materials, and circuit management, have partially mitigated these issues. However, they have also resulted in increased complexity in the fabrication process. Therefore, there is an urgent demand for a universal and simplified approach to address these challenges. To fulfill this need, this work presents a free-standing electrode and fixed surface tiny electrode implemented triboelectric nanogenerator (FFI-TENG). It is fabricated by a straightforward yet effective method: introducing a tiny electrode onto the surface of the tribo-negative material. This approach yields substantial enhancements in performance, notably a more than tenfold increase in output current density, a reduction in effective working frequencies, and a decrease in matching resistance as compared to vertical contact-separation TENGs (CS-TENGs) or single-electrode TENGs (SE-TENGs). Simultaneously, a comprehensive examination and proposition regarding the operational mechanism of FFI-TENG, highlighting its extensive applicability are also offered. Significantly, FFI-TENG excels in mechanical energy harvesting even under ultra-low working frequencies (0.1 Hz), outperforming similar contact-separation models. This innovation positions it as a practical and efficient solution for the development of low-entropy energy harvesters.

DOI： 10.1002/smll.202308531

Web of Science

Scopus

PubMed

The effect of room-temperature plastic deformation in darkness on the photoluminescence properties of ZnS 査読有り

Ogura, Y; Nakamura, A; Kameyama, T; Kurokawa, Y; Tochigi, E; Shibata, N; Torimoto, T; Hoshino, S; Yokoi, T; Matsunaga, K

JOURNAL OF THE AMERICAN CERAMIC SOCIETY 107 巻 ( 4 ) 頁： 2040 - 2047 2023年11月

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 the American Ceramic Society

Inorganic semiconductors have been considered to be brittle at room temperature generally, but recently zinc sulfide (ZnS), a II–VI compound semiconductor, was found to exhibit extraordinarily large plasticity even at room temperature if it was deformed in darkness. Room-temperature plastic deformation can achieve high density of glide dislocations in the crystal without significantly changing the point defect structure, and these dislocations themselves have a potential to provide unique functional properties different from those of the bulk. In this study, therefore, undoped ZnS crystals were plastically deformed at room temperature in darkness to generate only a large number of dislocations, and the changes in luminescence properties resulting from this process were investigated for the first time. As a result, we found that ZnS deformed in darkness exhibits characteristic photoluminescence and persistent luminescence emissions with a visible green color. SEM-CL analyses also identified the emissions from the dislocations. Theoretical calculations indicated that individual dislocations in ZnS have the ability to trap photo-excited carriers. Such changes in luminescence properties due to room temperature plastic deformation in darkness can be considered to originate from dislocations rather than point defects. In other words, the dislocations themselves serve as the significant recombination centers, realizing visible light emission.

DOI： 10.1111/jace.19564

Web of Science

Scopus

Improvement of passivation performance of silicon nanocrystal/silicon oxide compound layer by two-step hydrogen plasma treatment 査読有り

M. Matsumi, K. Gotoh, M. Wilde, Y. Kurokawa, K. Fukutani and N. Usami

Solar Energy Materials and Solar Cells 262 巻頁： 112538 2023年10月

Nanoscale Size Control of Si Pyramid Texture for Perovskite/Si Tandem Solar Cells Enabling Solution-Based Perovskite Top-Cell Fabrication and Improved Si Bottom-Cell Response 査読有り

Li, YQ; Sai, H; Mcdonald, C; Xu, ZH; Kurokawa, Y; Usami, N; Matsui, T

ADVANCED MATERIALS INTERFACES 10 巻 ( 35 ) 2023年9月

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

A monolithic perovskite/silicon tandem solar cell architecture is employed to surpass the single-junction efficiency limit. Recently, there is an increasing need for the double-sided textures in the Si bottom cell to be compatible with the solution-processed perovskite top cell from an industrial perspective. Herein, a silver-assisted alkaline etching method is applied to fabricate nanoscale Si pyramid textures, and the influence of varying pyramid size (400–900 nm) on the interface morphology and the performance of perovskite/Si tandem cells is investigated. It is demonstrated that electrical shunting starts to increase, and the open-circuit voltage (VOC) decreases when the texture size exceeds the perovskite thickness (~500nm) due to the non-uniform top-cell formation on a rough Si surface. However, when the texture size is reduced to 400–500 nm, all spin-coated perovskite top-cell component layers exhibit an even form over the nanopyramid Si, resulting in a high VOC and an enhanced Si bottom cell current (≈1.0 mA cm−2) due to the suppressed reflectance at the top/bottom cell interface without using optical couplers. The double-sided nanopyramid Si texture offers opportunities to increase tandem cell efficiency while reducing its production cost compared with the commonly used single-sided textured Si.

DOI： 10.1002/admi.202300504

Web of Science

Scopus

Impact of B<inf>2</inf>H<inf>6</inf>plasma treatment on contact resistivity in silicon heterojunction solar cells 査読有り

Gotoh K., Ozaki R., Morimura M., Tanaka A., Iseki Y., Nakamura K., Muramatsu K., Kurokawa Y., Ohshita Y., Usami N.

Japanese Journal of Applied Physics 62 巻 ( SK ) 2023年8月

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 investigated the effect of the B2H6 plasma treatment on p-type hydrogenated amorphous silicon (p-a-Si:H) surfaces for high-performance silicon heterojunction (SHJ) solar cells. Secondary ion mass spectroscopy measurements revealed that the boron concentration at the p-a-Si:H surface is increased by employing the B2H6 plasma treatment. Furthermore, specific contact resistance is decreased by about one-third after the B2H6 plasma treatment. No degradation of passivation performance is induced by the B2H6 plasma treatment. The power conversion efficiency of the SHJ solar cells with the B2H6 plasma treatment is improved by the increase in fill factor (FF) due to decreased series resistance and increased shunt resistance. From numerical simulations, the upward band bending is enhanced at the heterointerface between transparent conductive oxide (TCO) and p-a-Si:H by the B2H6 plasma treatment, which is responsible for the improved FF owing to facilitated tunneling holes from c-Si to p-a-Si:H layers and the TCO/p-a-Si:H heterointerface.

DOI： 10.35848/1347-4065/acc953

Scopus

Quantitative evaluation of implied open-circuit voltage after metal electrode deposition on TiO <inf>x</inf> /Si heterostructures by photoluminescence imaging: impact of metallization on passivation performance 査読有り

Fukaya S., Gotoh K., Matsui T., Sai H., Kurokawa Y., Usami N.

Japanese Journal of Applied Physics 62 巻 ( SK ) 2023年8月

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 degradation of surface passivation performance by metallization is a challenge in realizing highly efficient crystalline Si solar cells that use novel carrier-selective contacts. Here, we report on a simple method to study the effect of metallization on passivation of titanium oxide (TiOx)/Si heterostructures. We investigated the relationship between the implied open-circuit voltage (iV OC) and the photoluminescence (PL) intensity imaging of solar cell precursors before metallization. Based on the relationship obtained, the change of the iV OC before and after metallization on the TiOx was evaluated quantitatively. The results showed that the iV OC predicted by the PL measurement decreases by 23-104 mV after metal deposition and shows a good agreement with the measured V OC in the finished solar cells. These results demonstrate that the iV OC evaluation by PL measurement provides a good prediction of the V OC after metallization, which is useful in analyzing the passivation degradation induced by metallization.

DOI： 10.35848/1347-4065/acc813

Scopus

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