Updated on 2021/10/22

写真a

 
ARAIDAI Masaaki
 
Organization
Institute of Materials and Systems for Sustainability Center for Integrated Research of Future Electronics Multiphysics Simulation Section Assistant Professor
Graduate School
Graduate School of Engineering
Undergraduate School
School of Engineering
Title
Assistant Professor

Degree 1

  1. 博士(理学) ( 2007.9   東京理科大学 ) 

Research Interests 2

  1. Computational Material Science

  2. 表面・界面電子物性

Research Areas 2

  1. Nanotechnology/Materials / Thin film/surface and interfacial physical properties  / 表面・界面電子物性

  2. Nanotechnology/Materials / Nanomaterials  / 計算物質科学

Research History 5

  1. 未来材料・システム研究所 附属未来エレクトロニクス集積研究センター   助教

    2015.10

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    Country:Japan

  2. 名古屋大学 大学院工学研究科 量子工学専攻   助教

    2013.8 - 2015.9

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    Country:Japan

  3. 筑波大学 計算科学研究センター 研究員

    2012.8 - 2013.7

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    Country:Japan

  4. 東北大学 原子分子材料科学高等研究機構 産学官連携研究員

    2009.4 - 2012.7

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    Country:Japan

  5. 早稲田大学 ナノ理工学研究機構 客員講師(専任扱い)

    2007.11 - 2009.3

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    Country:Japan

Education 3

  1. Tokyo University of Science   Graduate School, Division of Natural Science

    2004.4 - 2007.9

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    Country: Japan

  2. Tokyo University of Science   Graduate School, Division of Natural Science

    2002.4 - 2004.3

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    Country: Japan

  3. Tokyo University of Science   Faculty of Science

    1998.4 - 2002.3

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    Country: Japan

Professional Memberships 4

  1. 日本表面科学会

  2. 日本磁気学会

  3. 日本物理学会

  4. 応用物理学会

Committee Memberships 3

  1. 日本物理学会第75回年次大会実行委員会   市民科学講演会担当  

    2018.12 - 2020.3   

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    Committee type:Academic society

  2. EXECUTIVE COMMITTEE of ICMASS2019   Web担当  

    2018.11 - 2019.12   

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    Committee type:Academic society

  3. EXECUTIVE COMMITTEE of ICMASS2017   Award担当  

    2016.6 - 2017.12   

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    Committee type:Academic society

Awards 7

  1. MNC 2017 Award for Outstanding Paper

    2018.11   31st International Microprocesses and Nanotechnology Conference Organizing Committee   Growth of Two-Dimensional Ge Crystal by Annealing of Heteroepitaxial Ag/Ge(111) under N<sub>2</sub> Ambient

    K. Ito, A. Ohta, M. Kurosawa, M. Araidai, M. Ikeda, K. Makihara, S. Miyazaki

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    Award type:International academic award (Japan or overseas)  Country:Japan

  2. 日本磁気学会論文賞

    2016.9   公益社団法人 日本磁気学会  

    高橋秀和,洗平昌晃,岡田晋,白石賢二

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    Award type:Honored in official journal of a scientific society, scientific journal  Country:Japan

  3. 日本磁気学会論文賞

    2016.9   公益社団法人 日本磁気学会   Theoretical Investigation on Electronic and Magnetic Structures of FeRh

    高橋秀和, 洗平昌晃, 岡田晋, 白石賢二

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  4. IWDTF Young Paper Award

    2015.11   Organizing Committee of 2015 International Workshop on DIELECTRIC THIN FILMS FOR FUTURE ELECTRON DEVICES -SCIENCE AND TECHNOLOGY-   Evaluation of Energy Band Structure of Si#D1-x#DRSn#Dx#DR by Density Functional Theory Calculation and Photoelectron Spectroscopy

    Y. Nagae, S. Shibayama, M. Kurosawa, M. Araidai, M. Sakashita, O. Nakatsuka, K. Shiraishi, and S. Zaima

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    Award type:Award from international society, conference, symposium, etc.  Country:Japan

  5. IWDTF Young Paper Award

    2015.11   Organizing Committee of 2015 International Workshop on DIELECTRIC THIN FILMS FOR FUTURE ELECTRON DEVICES -SCIENCE AND TECHNOLOGY-   Evaluation of Energy Band Structure of Si<sub>1-x</sub>Sn<sub>x</sub> by Density Functional Theory Calculation and Photoelectron Spectroscopy

    Y. Nagae, S. Shibayama, M. Kurosawa, M. Araidai, M. Sakashita, O. Nakatsuka, K. Shiraishi, S. Zaima

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    Award type:International academic award (Japan or overseas)  Country:Japan

  6. The 62nd JSAP Spring Meeting, 2015 Poster Award

    2015.3   First principles stucy on atomic defects in insulators of MONOS memory

    Hiroki Shirakawa, Masaaki Araidai, Katsumasa Kamiya, Kenji Shiraishi

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  7. The 62nd JSAP Spring Meeting, 2015 Poster Award

    2015.3   First principles stucy on atomic defects in insulators of MONOS memory

    Hiroki Shirakawa, Masaaki Araidai, Katsumasa Kamiya, Kenji Shiraishi

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    Award type:Award from international society, conference, symposium, etc.  Country:Japan

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Papers 88

  1. カリウムイオンエレクトレットにおける負電荷蓄積機構の第一原理計算による検討 Reviewed

    電気学会論文誌E   Vol. 141 ( 8 )   2021.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  2. In-plane strain-free stanene on a Pd2Sn(111) surface alloy

    Yuhara Junji, Ogikubo Tsuyoshi, Araidai Masaaki, Takakura Sho-ichi, Nakatake Masashi, Le Lay Guy

    PHYSICAL REVIEW MATERIALS   Vol. 5 ( 5 )   2021.5

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1103/PhysRevMaterials.5.053403

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  3. Theoretical study on the effect of H-2 and NH3 on trimethylgallium decomposition process in GaN MOVPE

    Sakakibara Soma, Chokawa Kenta, Araidai Masaaki, Kusaba Akira, Kangawa Yoshihiro, Shiraishi Kenji

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 60 ( 4 )   2021.4

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.35848/1347-4065/abf089

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  4. Theoretical study on the effect of H2 and NH3 on trimethylgalliumdecomposition process in GaN MOVPE Reviewed

    S. Sakakibara, K. Chokawa, M. Araidai, A. Kusaba, Y. Kangawa, and K. Shiraishi

    Japanese Journal of Applied Physics     page: in press   2021.4

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    Language:English   Publishing type:Research paper (scientific journal)  

  5. First-Principles Calculation of Copper Oxide Superconductors That Supports the Kamimura-Suwa Model

    Hiroshi Kamimura, Masaaki Araidai, Kunio Ishida, Shunichi Matsuno, Hideaki Sakata, Kenji Shiraishi, Osamu Sugino, Jaw-Shen Tsai

    Condensed Matter   Vol. 5 ( 4 )   2020.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.3390/condmat5040069

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  6. Negative-charge-storing mechanism of potassium-ion SiO2-based electrets for vibration-powered generators

    Toru Nakanishi, Takeshi Miyajima, Kenta Chokawa, Masaaki Araidai, Hiroshi Toshiyoshi, Tatsuhiko Sugiyama, Gen Hashiguchi, Kenji Shiraishi

    Applied Physics Letters   Vol. 117 ( 19 )   2020.11

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0029012

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  7. Hydrogen desorption from silicane and germanane crystals: Toward creation of free-standing monolayer silicene and germanene Reviewed

    Masaaki Araidai, Mai Itoh, Masashi Kurosawa, Akio Ohta, Kenji Shiraishi

    Journal of Applied Physics   Vol. 128 ( 12 )   2020.9

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/5.0018855

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  8. Thermodynamic analysis of the gas phase reaction of Mg-doped GaN growth by HVPE using MgO

    Kimura Tomoya, Ohnishi Kazuki, Amano Yuki, Fujimoto Naoki, Araidai Masaaki, Nitta Shugo, Honda Yoshio, Amano Hiroshi, Kangawa Yoshihiro, Shiraishi Kenji

    JAPANESE JOURNAL OF APPLIED PHYSICS   Vol. 59 ( 8 )   2020.8

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  9. Epitaxial growth of honeycomb-like stanene on Au(111) Reviewed International coauthorship

    Pang, W., Nishino, K., Ogikubo, T., Araidai, M., Nakatake, M., Le Lay, G., Yuhara, J.

    Applied Surface Science   Vol. 517   2020.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.apsusc.2020.146224

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  10. Continuous Growth of Germanene and Stanene Lateral Heterostructures Reviewed International coauthorship

    Ogikubo, T., Shimazu, H., Fujii, Y., Ito, K., Ohta, A., Araidai, M., Kurosawa, M., Le Lay, G., Yuhara, J.

    Advanced Materials Interfaces   Vol. 7 ( 10 )   2020.5

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1002/admi.201902132

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  11. Formation of ultrathin segregated-Ge crystal on Al/Ge(111) surface Reviewed

    Kobayashi, M., Ohta, A., Kurosawa, M., Araidai, M., Taoka, N., Simizu, T., Ikeda, M., Makihara, K., Miyazaki, S.

    Japanese Journal of Applied Physics   Vol. 59 ( SG )   2020.4

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.35848/1347-4065/ab69de

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  12. Thermodynamic analysis of the gas phase reaction of Mg-doped GaN growth by HVPE using MgO Reviewed

    Kimura, T., Ohnishi, K., Amano, Y., Fujimoto, N., Araidai, M., Nitta, S., Honda, Y., Amano, H., Kangawa, Y., Shiraishi, K.

    Japanese Journal of Applied Physics   Vol. 59 ( 8 )   2020

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    DOI: 10.35848/1347-4065/aba0d5

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  13. Morphology and Electronic Structure of Sn-Intercalated TiS<inf>2</inf>(0001) Layers Reviewed International coauthorship

    Yuhara, J., Isobe, N., Nishino, K., Fujii, Y., Chan, L.H., Araidai, M., Nakatake, M.

    Journal of Physical Chemistry C   Vol. 123 ( 36 ) page: 22293 - 22298   2019.9

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    © 2019 American Chemical Society. The surface morphology and electronic structure of layered semiconductor 1-trigonal phase titanium disulfide, i.e., 1T-TiS2(0001), with Sn intercalation, have been studied by scanning tunneling microscopy (STM), low-energy electron diffraction, synchrotron radiation photoemission spectroscopy, and first-principles calculations based on density functional theory (DFT). From the STM images, we show that Sn atoms are intercalated into TiS2 layers. The electronic structure exhibits electron Fermi pockets around M points and characteristic band dispersions around the M and K points after Sn intercalation. The DFT calculations reveal the geometrical site of intercalated Sn atom, which is surrounded by six sulfur atoms with D3d symmetry. The calculated electronic band structures are in good agreement with the experimental band structure.

    DOI: 10.1021/acs.jpcc.9b05492

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  14. Theoretical studies on the switching mechanism of VMCO memories Reviewed

    Nakanishi, T., Chokawa, K., Araidai, M., Nakayama, T., Shiraishi, K.

    Microelectronic Engineering   Vol. 215   page: 110997(1)-(4)   2019.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    © 2019 Elsevier B.V. In this work, we propose a new switching model for Vacancy Modulated Conductive Oxide (VMCO) memories which are non-filamentary resistive switching memories. In recent years, attention has been drawn to VMCO memories because the current through them depends on the area of the device. Since the switching mechanism in VMCO memories has not yet been clarified, we carried out first principles calculations to study this phenomenon. Previous studies have shown that a current path is created by the oxygen vacancies (Vo) in TiO2. We discovered that the formation and disappearance of Vo near the TiO2/a-Si interface in TiO2 can be controlled by applying a voltage, and that this could be used to control the current. From this, we proposed a new switching model for VMCO memories.

    DOI: 10.1016/j.mee.2019.110997

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  15. Electronic structure analysis of core structures of threading dislocations in GaN Reviewed

    Takashi Nakano, Kenta Chokawa, Masaaki Araidai, Kenji Shiraishi, Atsushi Oshiyama, Akira Kusaba, Yoshihiro Kangawa, Atsushi Tanaka, Yoshio Honda, Hiroshi Amano

    2019 Compound Semiconductor Week, CSW 2019 - Proceedings     2019.5

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    © 2019 IEEE. It is known that threading dislocations degrade the performance of GaN-based electronic devices. Electronic structure of threading dislocations in GaN is not fully understood. Accordingly, we examine the electronic structures of threading dislocations in GaN using first principles calculations based on density functional theory (DFT) and to clarify the origin of the leakage current. We have comprehensively studied the relation between threading core structures and electronic property in GaN thin films. Our calculation models of threading dislocations are the edge dislocations with Burgers vectors of 1/3 [11-20] and the screw dislocations with Burgers vectors of [0001]. We examined various core types of the threading dislocations. We found that both edge dislocations and screw dislocations do not cause the leakage currents in n-type GaN based devices because no defect level appears near the conduction band bottom.

    DOI: 10.1109/ICIPRM.2019.8819270

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  16. Influence of edge magnetization and electric fields on zigzag silicene, germanene and stanene nanoribbons Reviewed International journal

    Hattori, A., Yada, K., Araidai, M., Sato, M., Shiraishi, K., Tanaka, Y.

    Journal of Physics Condensed Matter   Vol. 31 ( 10 ) page: 105302 - 105302   2019.3

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    Using a multi-orbital tight-binding model, we have studied the edge states of
    zigzag silicene, germanene, and stanene nanoribbons (ZSiNRs, ZGeNRs and ZSnNRs,
    respectively) in the presence of the Coulomb interaction and a vertical
    electric field. The resulting edge states have non-linear energy dispersions
    due to multi-orbital effects, and the nanoribbons show induced magnetization at
    the edges. Owing to this non-linear dispersion, ZSiNRs, ZGeNRs and ZSnNRs may
    not provide superior performance in field effect transistors, as has been
    proposed from single-orbital tight-binding model calculations. We propose an
    effective low-energy model that describes the edge states of ZSiNRs, ZGeNRs,
    and ZSnNRs. We demonstrate that the edge states of ZGeNR and ZSnNR show
    anti-crossing of bands with opposite spins, even if only out-of-plane edge
    magnetization is present. The ability to tune the spin polarizations of the
    edge states by applying an electric field points to future opportunities to
    fabricate silicene, germanene and stanene nanoribbons as spintronics devices.

    DOI: 10.1088/1361-648X/aaf8ce

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  17. Physical origin of excellent data retention over 10years at sub-μA operation in AgW-alloy ionic memory Reviewed

    Marina Yamaguchi, Shosuke Fujii, Yoko Yoshimura, Riki Nagasawa, Yoshihiro Asayama, Hiroki Shirakawa, Masaaki Araidai, Kenji Shiraishi, Takashi Nakayama, Masumi Saitoh

    2019 IEEE 11th International Memory Workshop, IMW 2019     page: 1 - 3   2019

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    © 2019 IEEE. We clarify the physical origin of excellent performance and reliability in AgW-alloy ionic memory. AgW-alloy ionic memory shows low operation current in sub-μA range, good data retention and low operation voltage, which are desirable characteristics for high-density cross-point applications. Mechanisms of the improvements in AgW alloy devices compared to pure Ag and AgTi alloy devices are discussed based on first-principles calculations. We find that large cohesive energy of W is a key for improving data retention while keeping low operation voltage in AgW-alloy ionic memory.

    DOI: 10.1109/IMW.2019.8739678

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  18. Electronic structure analysis of core structures of threading dislocations in GaN

    Nakano Takashi, Chokawa Kenta, Araidai Masaaki, Shiraishi Kenji, Oshiyama Atsushi, Kusaba Akira, Kangawa Yoshihiro, Tanaka Atsushi, Honda Yoshio, Amano Hiroshi

    2019 COMPOUND SEMICONDUCTOR WEEK (CSW)     2019

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  19. Effect of incorporating Hf atoms in AlON gate dielectrics on hole leakage current Reviewed

    T. Nagura, K. Chokawa, M. Araidai, T. Hosoi, H. Watanabe, A. Oshiyama, K. Shiraishi

        2018.12

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  20. Germanene Epitaxial Growth by Segregation through Ag(111) Thin Films on Ge(111) Reviewed International journal

    Yuhara, J., Shimazu, H., Ito, K., Ohta, A., Araidai, M., Kurosawa, M., Nakatake, M., Le Lay, G.

    ACS Nano   Vol. 12 ( 11 ) page: 11632 - 11637   2018.11

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    © 2018 American Chemical Society. Large-scale two-dimensional sheets of graphene-like germanium, namely, germanene, have been epitaxially prepared on Ag(111) thin films grown on Ge(111), using a segregation method, differing from molecular beam epitaxy used in previous reports. From the scanning tunneling microscopy (STM) images, the surface is completely covered with an atom-thin layer showing a highly ordered long-range superstructure in wide scale. Two types of protrusions, named hexagon and line, form a (7âš7 × 7âš7)R19.1° supercell with respect to Ag(111), with a very large periodicity of 5.35 nm. Auger electron spectroscopy and high-resolution synchrotron radiation photoemission spectroscopy demonstrate that Ge atoms are segregated on the Ag(111) surface as an overlayer. Low-energy electron diffraction clearly shows incommensurate "(1.35 × 1.35)"R30° spots, corresponding to a lattice constant of 0.39 nm, in perfect accord with close-up STM images, which clearly reveal an internal honeycomb arrangement with corresponding parameter and low buckling within 0.01 nm. As this 0.39 nm value is in good agreement with the theoretical lattice constant of free-standing germanene, conclusively, the segregated Ge atoms with trivalent bonding in honeycomb configuration form a characteristic two-dimensional germanene-like structure.

    DOI: 10.1021/acsnano.8b07006

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  21. Effects of annealing with CO and CO<inf>2</inf> molecules on oxygen vacancy defect density in amorphous SiO<inf>2</inf> formed by thermal oxidation of SiC Reviewed

    Chokawa, K., Araidai, M., Shiraishi, K.

    Journal of Applied Physics   Vol. 124 ( 13 ) page: 135701(1)-(5)   2018.10

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    © 2018 Author(s). SiO2 formed by the thermal oxidation of SiC has numerous defects, and the stoichiometry of the SiO2 near the SiC/SiO2 interface differs from that of SiO2 near the Si/SiO2 interface. We assume that, during the oxidation of SiC, CO and CO2 molecules are released, and that these molecules interact with the SiO2 and form defects. Considering the Gibbs free energy of these molecules, we found that CO molecules reduce part of the amorphous SiO2 at high temperatures, resulting in the formation of oxygen vacancy defects concomitant with the formation of CO2 molecules. In particular, when the partial pressure of the CO molecules is higher than that of the CO2 molecules, the number of oxygen vacancy defects increases. This means that post-oxidation annealing with CO molecules induces defects and degrades the breakdown field of SiO2. On the other hand, when the partial pressure of the CO2 molecules is larger than that of the CO molecules, reduction by the CO molecules does not occur, and the CO2 molecules can oxidize oxygen vacancy defects in SiO2. This means that post-oxidation annealing with CO2 molecules enables recovery of the oxygen vacancy defects and improves the breakdown field and flatband shift of SiO2 gate dielectrics. Accordingly, it is possible to reduce the formation of oxygen vacancies in amorphous SiO2 by performing post-oxidation annealing in a CO2 gas ambient.

    DOI: 10.1063/1.5041794

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  22. First-principles calculations of the effect of incorporating Hf atoms in AlON gate dielectrics of wide-bandgap-semiconductor power devices on the hole leakage current Reviewed

    Takuya Nagura, Kenta Chokawa, Masaaki Araidai, Takuji Hosoi, Heiji Watanabe, Atsushi Oshiyama, Kenji Shiraishi

        2018.9

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  23. Theoretical study of the atomistic behavior of O vacancy complexes with N and H atoms in the SiO<inf>2</inf> layer of a metal-oxide-nitride-oxide-semiconductor memory: Physical origin of the irreversible threshold voltage shift observed in metal-oxide-nitride-oxide-semiconductor memories Reviewed

    Shirakawa, H., Araidai, M., Kamiya, K., Shiraishi, K.

    Japanese Journal of Applied Physics   Vol. 57 ( 8 ) page: 81101 - 81101   2018.8

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    © 2018 The Japan Society of Applied Physics. Metal-oxide-nitride-oxide-semiconductor (MONOS) memories are attracting considerable interest for use as next-generation three-dimensional (3D) NAND flash memories; however, these memories have a serious reliability issue, that is, the irreversible threshold voltage shift arising from the generation of interface states at the Si/SiO2 interface due to program/erase (P/E) cycling. The clarification of the origin of this shift is essential in order to enable us to design high-reliability MONOS devices in the future. We clarified from first-principles calculations that defects consisting of an O vacancy and two substituent N atoms, (NO)2VO, are generated in SiO2, and that these turn into positively charged NSi2H2+ defects by trapping protons when a negative gate bias is applied. Furthermore, we found that thermal treatment in H2 atmosphere prevents (NO)2VO defects from turning into NSi2H2+ defects. This work clearly shows that proton trapping by (NO)2VO defects in SiO2 is the cause of interface state generation, leading to irreversible threshold voltage shifts during P/E cycling.

    DOI: 10.7567/JJAP.57.081101

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  24. Growth of two-dimensional Ge crystal by annealing of heteroepitaxial Ag/Ge(111) under N<inf>2</inf> ambient Reviewed

    Ito, K., Ohta, A., Kurosawa, M., Araidai, M., Ikeda, M., Makihara, K., Miyazaki, S.

    Japanese Journal of Applied Physics   Vol. 57 ( 6 ) page: 06HD08 - 06HD08   2018.6

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    © 2018 The Japan Society of Applied Physics. The growth of a two-dimensional crystal of Ge atoms on an atomically flat Ag(111) surface has been demonstrated by the thermal annealing of a heteroepitaxial Ag/Ge structure in N2 ambient at atmospheric pressure. The surface morphology and chemical bonding features of heteroepitaxial Ag(111) grown on wet-cleaned Ge(111) after annealing at different temperatures and for various times have been systematically investigated to control the surface segregation of Ge atoms and the planarization of the heteroepitaxial Ag(111) surface.

    DOI: 10.7567/JJAP.57.06HD08

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  25. Effect of incorporation of nitrogen atoms in Al<inf>2</inf>O<inf>3</inf> gate dielectric of wide-bandgap-semiconductor MOSFET on gate leakage current and negative fixed charge Reviewed

    Kojima, E., Chokawa, K., Shirakawa, H., Araidai, M., Hosoi, T., Watanabe, H., Shiraishi, K.

    Applied Physics Express   Vol. 11 ( 6 ) page: 61501 - 61501   2018.6

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Japan Society of Applied Physics  

    © 2018 The Japan Society of Applied Physics. We performed first-principle calculations to investigate the effect of incorporation of N atoms into Al2O3 gate dielectrics. Our calculations show that the defect levels generated by VO in Al2O3 are the origin of the stress-induced gate leakage current and that VOVAl complexes in Al2O3 cause negative fixed charge. We revealed that the incorporation of N atoms into Al2O3 eliminates the VO defect levels, reducing the stress-induced gate leakage current. Moreover, this suppresses the formation of negatively charged VOVAl complexes. Therefore, AlON can reduce both stress-induced gate leakage current and negative fixed charge in wide-bandgap-semiconductor MOSFETs.

    DOI: 10.7567/APEX.11.061501

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  26. First principles investigation of the unipolar resistive switching mechanism in an interfacial phase change memory based on a GeTe/Sb<inf>2</inf>Te<inf>3</inf> superlattice Reviewed

    Shirakawa, H., Araidai, M., Shiraishi, K.

    Japanese Journal of Applied Physics   Vol. 57 ( 4 ) page: 04FE08 - 04FE08   2018.4

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    © 2018 The Japan Society of Applied Physics. The interfacial phase change memory (iPCM) based on a GeTe/Sb2Te 3 superlattice is one of the candidates for future storage class memories. However, the atomic structures of the high and low resistance states (HRS/LRS) remain unclear and the resistive switching mechanism is still under debate. Clarifying the switching mechanism is essential for developing further high-reliability and low-power-consumption iPCM. We propose, on the basis of the results of first-principles molecular dynamics simulations, a mechanism for resistive switching, and describe the atomic structures of the high and low resistance states of iPCM for unipolar switching. Our simulations indicated that switching from HRS to LRS occurs with Joule heating only, while that from LRS to HRS occurs with both hole injection and Joule heating.

    DOI: 10.7567/JJAP.57.04FE08

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  27. Investigation of the GaN/Al<inf>2</inf>O<inf>3</inf> Interface by First Principles Calculations Reviewed

    Chokawa, K., Kojima, E., Araidai, M., Shiraishi, K.

    Physica Status Solidi (B) Basic Research   Vol. 255 ( 4 ) page: 1700323 (1)-(4)   2018.4

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    © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Metal–oxide–semiconductor field effect transistors (MOSFETs) based on GaN have been studied for high-power performance because of the wide bandgap of GaN. Although Al2O3 is a promising dielectric film for GaN power devices, the interface structure of GaN/Al2O3 has not been revealed microscopically. We prepared two interface models with Ga–O bonds and Ga–Al bonds at the interface. Because the Ga–O bond is stronger than the Ga–Al bond, the Ga–O bonds are preferentially formed at the interface. When the Ga–Al bonds appear at the interface, they introduce defect levels in the bandgap of GaN. On the other hand, when the interface consists of Ga–O bonds, some defect structures can appear depending on the oxygen density. In oxygen-rich conditions, dangling bonds appear at the N atoms and their states appear around the valence band maximum.

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  28. Thermodynamic analysis of trimethylgallium decomposition during GaN metal organic vapor phase epitaxy Reviewed

    Sekiguchi, K., Shirakawa, H., Chokawa, K., Araidai, M., Kangawa, Y., Kakimoto, K., Shiraishi, K.

    Japanese Journal of Applied Physics   Vol. 57 ( 4 ) page: 04FJ03 - 04FJ03   2018.4

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    © 2018 The Japan Society of Applied Physics. We analyzed the decomposition of Ga(CH3)3 (TMG) during the metal organic vapor phase epitaxy (MOVPE) of GaN on the basis of first-principles calculations and thermodynamic analysis. We performed activation energy calculations of TMG decomposition and determined the main reaction processes of TMG during GaN MOVPE. We found that TMG reacts with the H2 carrier gas and that (CH3)2GaH is generated after the desorption of the methyl group. Next, (CH3)2GaH decomposes into (CH3)GaH2 and this decomposes into GaH3. Finally, GaH3 becomes GaH. In the MOVPE growth of GaN, TMG decomposes into GaH by the successive desorption of its methyl groups. The results presented here concur with recent highresolution mass spectroscopy results.

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  29. Segregated SiGe ultrathin layer formation and surface planarization on epitaxial Ag(111) by annealing of Ag/SiGe(111) with different Ge/(Si + Ge) compositions Reviewed

    Ito, K., Ohta, A., Kurosawa, M., Araidai, M., Ikeda, M., Makihara, K., Miyazaki, S.

    Japanese Journal of Applied Physics   Vol. 57 ( 4 ) page: 04FJ05 - 04FJ05   2018.4

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    © 2018 The Japan Society of Applied Physics. Two-dimensional (2D) crystals of Si and Ge atoms such as silicene and germanene are currently receiving much attention because of their exceptional electronic properties. We have studied the growth of ultrathin Si and Ge layers by the segregation of Si and Ge atoms on the Ag surface from the substrate by annealing the Ag/Si(111), Ag/Ge(111), and Ag/Si0.5Ge0.5(111) structures. After the epitaxial growth of the Ag(111) layer on the substrate by thermal evaporation, the stability of the Ag surface was also investigated for use as the template of ultrathin Si and Ge crystals. After annealing a ∼90-nm-thick Ag(111)/Ge(111) structure at 450°C in N2 ambience for 2h, the surface segregation of Ge and a flat Ag surface were demonstrated.

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  30. First-principles calculations of orientation dependence of Si thermal oxidation based on Si emission model Reviewed

    Nagura, T., Kawachi, S., Chokawa, K., Shirakawa, H., Araidai, M., Kageshima, H., Endoh, T., Shiraishi, K.

    Japanese Journal of Applied Physics   Vol. 57 ( 4 ) page: 04FB06 - 04FB06   2018.4

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    © 2018 The Japan Society of Applied Physics. It is expected that the off-state leakage current of MOSFETs can be reduced by employing vertical body channel MOSFETs (V-MOSFETs). However, in fabricating these devices, the structure of the Si pillars sometimes cannot be maintained during oxidation, since Si atoms sometimes disappear from the Si/oxide interface (Si missing). Thus, in this study, we used first-principles calculations based on the density functional theory, and investigated the Si emission behavior at the various interfaces on the basis of the Si emission model including its atomistic structure and dependence on Si crystal orientation. The results show that the order in which Si atoms are more likely to be emitted during thermal oxidation is (111) > (110) > (310) > (100). Moreover, the emission of Si atoms is enhanced as the compressive strain increases. Therefore, the emission of Si atoms occurs more easily in V-MOSFETs than in planar MOSFETs. To reduce Si missing in V-MOSFETs, oxidation processes that induce less strain, such as wet or pyrogenic oxidation, are necessary.

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  31. Theoretical study of the electronic structure of threading edge dislocations in GaN Reviewed

    Takashi Nakano, Masaaki Araidai, Kenji Shiraishi, Atsushi Tanaka, Yoshio Honda, Hiroshi Amano

    ECS Transactions   Vol. 86 ( 12 ) page: 41 - 49   2018

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    ©The Electrochemical Society. It is very important to fabricate high-quality GaN especially used for power devices. However, threading dislocations degrade the performance of GaN-based electronic devices. It is necessary to examine the electronic behavior at threading dislocations in GaN and to clarify the origin of the leakage current. As for theoretical studies, the electronic structure of threading dislocations in GaN is not fully understood. We investigated whether threading edge dislocations contribute to the leakage current or not. To do this, we used first principles calculations based on density functional theory (DFT) to examine the electronic structure at threading edge dislocations with Burgers vectors of 1/3[11-20]. We examined four core types of atomic structure at threading edge dislocations which contains about 200 atoms. Compared with dislocation line energies of each core configurations, it was found that the 5/7-atoms ring core and 8-atoms ring core are energetically stable. Then, we analyzed the electronic densities of states of each core configurations, and it was found that all types of core configurations at threading edge dislocations do not contribute to leakage current in n-type GaN-based devices.

    DOI: 10.1149/08612.0041ecst

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  32. First-principles study on adsorption structure and electronic state of stanene on a-alumina surface Reviewed

    Araidai, M., Kurosawa, M., Ohta, A., Shiraishi, K.

    Japanese Journal of Applied Physics   Vol. 56 ( 9 ) page: 95701 - 95701   2017.9

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    © 2017 The Japan Society of Applied Physics. The adsorption structure and electronic state of stanene on an a-Al2O3(0001) 1'1 surface were investigated by first-principles calculations. The variation in the electronic state of the adsorbed stanene from that of the free-standing one increased with the stanene-alumina distance, because the strength of the stanene-alumina interaction increased with the distance. The band splitting induced by the Rashba effect was observed in the electronic band structures. It was observed from the band structures with spin-orbit interactions that the degrees of band-gap opening due to the spin-orbit interactions were much lower than that due to the interaction between stanene and the a-alumina surface. By population analyses for chemical bonds, we revealed that the electronic state of stanene on the a-alumina surface was affected by Sn-O bonds with antibonding nature.

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  33. First principles investigation of SiC/AlGaN(0001) band offset Reviewed

    Kojima, E., Endo, K., Shirakawa, H., Chokawa, K., Araidai, M., Ebihara, Y., Kanemura, T., Onda, S., Shiraishi, K.

    Journal of Crystal Growth   Vol. 468 ( 15 ) page: 758 - 760   2017.6

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    © 2016 Elsevier B.V. We are attempting to develop a new type of vertical MOSFET with SiC/AlGaN heterojunction. Toward the realization of the vertical MOSFET, the control of conduction-band offset is one of the crucial subjects. We investigated the conduction-band offset of 4H-SiC/AlxGa1-xN interface by the first-principles electronic structure calculations. We found that the offset of the interface with 40% Al content becomes almost zero. Therefore, 4H-SiC/Al0.4Ga0.6N interface is one of the most promising candidates for the vertical MOSFET in future power conversion devices.

    DOI: 10.1016/j.jcrysgro.2016.11.066

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  34. First-principles and thermodynamic analysis of trimethylgallium (TMG) decomposition during MOVPE growth of GaN Reviewed

    Sekiguchi, K., Shirakawa, H., Yamamoto, Y., Araidai, M., Kangawa, Y., Kakimoto, K., Shiraishi, K.

    Journal of Crystal Growth   Vol. 468 ( 15 ) page: 950 - 953   2017.6

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    © 2016 Elsevier B.V. We analyzed the decomposition mechanisms of trimethylgallium (TMG) used for the gallium source of GaN fabrication based on first-principles calculations and thermodynamic analysis. We considered two conditions. One condition is under the total pressure of 1 atm and the other one is under metal organic vapor phase epitaxy (MOVPE) growth of GaN. Our calculated results show that H2 is indispensable for TMG decomposition under both conditions. In GaN MOVPE, TMG with H2 spontaneously decomposes into Ga(CH3) and Ga(CH3) decomposes into Ga atom gas when temperature is higher than 440 K. From these calculations, we confirmed that TMG surely becomes Ga atom gas near the GaN substrate surfaces.

    DOI: 10.1016/j.jcrysgro.2016.12.044

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  35. Defect formation in SiO<inf>2</inf> formed by thermal oxidation of SiC Reviewed

    Kenta Chokawa, Masaaki Araidai, Kenji Shiraishi

    2017 IEEE Electron Devices Technology and Manufacturing Conference, EDTM 2017 - Proceedings     page: 242 - 243   2017.6

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    © 2017 IEEE. In general, an insulating film of SiC MOSFET is SiO2 formed by thermal oxidation of SiC. This SiO2 film has many defect structures which induce much larger threshold voltage shift. In this paper, we investigated the defect formation of an oxygen vacancy in SiO2 by SiC thermal oxidation, using the first-principles calculations, and we found that the oxygen vacancy defect can be generated in the amorphous SiO2 at high temperature.

    DOI: 10.1109/EDTM.2017.7947582

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  36. エピタキシャルAg(111)上の極薄IV族結晶形成

    伊藤公一, 大田晃生, 黒澤昌志, 洗平昌晃, 池田弥央, 牧原克典, 宮崎誠一

    電子情報通信学会 信学技報     page: Vol. 117, No. 101, pp. 43-48   2017.6

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  37. Evaluation of energy band offset of Si1%xSnx semiconductors by numerical calculation using density functional theory Reviewed

    Nagae, Y., Kurosawa, M., Araidai, M., Nakatsuka, O., Shiraishi, K., Zaima, S.

    Japanese Journal of Applied Physics   Vol. 56 ( 4 ) page: 04CR10 - 04CR10   2017.4

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    © 2017 The Japan Society of Applied Physics. We examined the numerical calculation for evaluating the energy band offset of Si1%xSnx semiconductors and compared our calculation results with the results of previous theoretical calculation and experimental estimation. By estimating the charge neutrality level of Si1%xSnx as a mutual basis level for comparison of the first-principles calculations for different Si1%xSnx contents, the calculated valence band offset of Si1%xSnx to Si was found to sensitively shift with upward bowing with increasing Sn content compared with that obtained using a conventional linear interpolation model. This is in good agreements with the experimental result.

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  38. Thermodynamic considerations of the vapor phase reactions in III-nitride metal organic vapor phase epitaxy Reviewed

    Sekiguchi, K., Shirakawa, H., Chokawa, K., Araidai, M., Kangawa, Y., Kakimoto, K., Shiraishi, K.

    Japanese Journal of Applied Physics   Vol. 56 ( 4 ) page: 04CJ04 - 04CJ04   2017.4

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    © 2017 The Japan Society of Applied Physics. We analyzed the metal organic vapor phase epitaxial growth mechanism of the III-nitride semiconductors GaN, AlN, and InN by first-principles calculations and thermodynamic analyses. In these analyses, we investigated the decomposition processes of the group III source gases X(CH3)3 (X = Ga, Al, In) at finite temperatures and determined whether the (CH3)2GaNH2 adduct can be formed or not. The results of our calculations show that the (CH3)2GaNH2 adduct cannot be formed in the gas phase in GaN metal organic vapor phase epitaxy (MOVPE), whereas, in AlN MOVPE, the formation of the (CH3)2AlNH2 adduct in the gas phase is exclusive. In the case of GaN MOVPE, trimethylgallium (TMG, [Ga(CH3)3]) decomposition into Ga gas on the growth surface with the assistance of H2 carrier gas, instead of the formation of the (CH3)2GaNH2 adduct, occurs almost exclusively. Moreover, in the case of InN MOVPE, the formation of the (CH3)2InNH2 adduct does not occur and it is relatively easy to produce In gas even without H2 in the carrier gas.

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  39. Edge states of hydrogen terminated monolayer materials: Silicene, germanene and stanene ribbons Reviewed International journal

    Hattori, A., Tanaya, S., Yada, K., Araidai, M., Sato, M., Hatsugai, Y., Shiraishi, K., Tanaka, Y.

    Journal of Physics Condensed Matter   Vol. 29 ( 11 ) page: 115302 - 115302   2017

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    We investigate the energy dispersion of the edge states in zigzag silicene,
    germanene and stanene nanoribbons with and without hydrogen termination based
    on a multi-orbital tight-binding model. Since the low buckled structures are
    crucial for these materials, both the $\pi$ and $\sigma$ orbitals have a strong
    influence on the edge states, different from the case for graphene nanoribbons.
    The obtained dispersion of helical edge states is nonlinear, similar to that
    obtained by first-principles calculations. On the other hand, the dispersion
    derived from the single-orbital tight-binding model is always linear.
    Therefore, we find that the non-linearity comes from the multi-orbital effects,
    and accurate results cannot be obtained by the single-orbital model but can be
    obtained by the multi-orbital tight-binding model. We show that the
    multi-orbital model is essential for correctly understanding the dispersion of
    the edge states in tetragen nanoribbons with a low buckled geometry.

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  40. Possibility of Metal-Oxide-Nitride-Oxide-Semiconductor Memories for Long Lifespan Archive Memories. Reviewed

    Hiroki Shirakawa, Keita Yamaguchi, Masaaki Araidai, Katsumasa Kamiya, Kenji Shiraishi

    IEICE Transactions   Vol. 100-C ( 10 ) page: 928 - 933   2017

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    Copyright © 2017 The Institute of Electronics, Information and Communication Engineers We demonstrate on the basis of ab initio calculations that metal-oxide-nitride-oxide-semiconductor (MONOS) memory is one of the most promising future high-density archive memories. We find that O related defects in a MONOS memory cause irreversible structural changes to the SiO2/Si3N4 interface at the atomistic level during program/erase (P/E) cycles. Carrier injection during the programming operation makes the structure energetically very stable, because all the O atoms in this structure take on three-fold-coordination. The estimated lifespan of the programmed state is of the order of a thousand years.

    DOI: 10.1587/transele.E100.C.928

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  41. First principles and themodynamical studies on matel organic vaper phase epitaxy of GaN Reviewed

    Kenji Shiraishi, Kazuki Sekiguchi, Hiroki Shirakawa, Kenta Chokawa, Masaaki Araidai, Yoshihiro Kangawa, Koichi Kakimoto

    ECS Transactions   Vol. 80 ( 1 ) page: 295 - 301   2017

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    © The Electrochemical Society. We analyzed metal organic vapor phase epitaxy growth mechanism of Ill-nitride semiconductors, GaN, A1N and InN based on first-principles calculations and thermodynamic analysis. With this calculated methods, we investigate the decomposition process of the group III source gases, X(CH3)3 (X = Ga, Al, In) at finite temperatures and whether the (CH3)3 AlNH2 adduct can be formed or not. Our calculated results show that (CH3)2 GaNH2 adduct cannot be formed in the gas phase reaction in GaN MOVPE. Whereas, (CH3)2AINH2 adduct can be formed so much in gas phase in A1N MOVPE. In case of GaN MOVPE, trimethylgallium (TMG, [Ga(CH3)3]) almost decomposes into Ga gas on growth surface by the assistance of H2 carrier gas instead of (CH3)2GaNH2 adduct formation. Moreover, in case of InN MOVPE, (CH3)2lnNH2 adduct formation cannot occur and it is relatively easy that In gas is produced even if there is no H2 carrier gas.

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  42. Defect Formation in SiO2 Formed by Thermal Oxidation of SiC

    Chokawa Kenta, Araidai Masaaki, Shiraishi Kenji

    2017 IEEE ELECTRON DEVICES TECHNOLOGY AND MANUFACTURING CONFERENCE (EDTM)     page: 242-243   2017

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  43. 金属誘起層交換法によるAg上Si,Ge極薄膜の形成-シリセン,ゲルマネンの創製を目指して- Reviewed

    黒澤昌志,大田晃生,洗平昌晃,財満鎭明

    表面科学   Vol. 37 ( 8 ) page: 374-379   2016.8

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  44. Surface-segregated Si and Ge ultrathin films formed by Ag-induced layer exchange process Reviewed

    Kurosawa, M., Ohta, A., Araidai, M., Zaima, S.

    Japanese Journal of Applied Physics   Vol. 55 ( 8 ) page: 08NB07 - 08NB07   2016.8

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    © 2016 The Japan Society of Applied Physics. We have developed a new method of growing Si or Ge ultrathin films on a Ag(111) surface by using a Ag-induced layer exchange (ALEX) process toward the creation of 2D honeycomb sheets of Si and Ge, known as silicene and germanene, respectively. In the present paper, we clarify ALEX features, specifically the surface segregation of Si (or Ge) atoms from the underlying substrate, focusing on the annealing temperature and time. Hard X-ray photoelectron spectroscopy analyses demonstrate that surface-segregated Si (or Ge) exists on the Ag surfaces after the epitaxial growth of the Ag layer on Si(111) [or Ge(111)] substrates; the amount of segregated Si (or Ge) can be controlled by a subsequent annealing. Also, we find that the segregation of an ultrathin Si or Ge layer proceeds at an interface between Ag and the AlOx capping layer.

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  45. Density functional study for crystalline structures and electronic properties of Si1-xSnx binary alloys Reviewed

    Y. Nagae, M. Kurosawa, S. Shibayama, M. Araidai, M. Sakashita, O. Nakatsuka, K. Shiraishi, S. Zaima

    Japanese Journal of Applied Physics   Vol. 55 ( 8 ) page: 08PE04   2016.7

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    DOI: 10.7567/JJAP.55.08PE04

  46. Surface-segregated Si and Ge ultrathin films formed by Ag-induced layer exchange process Reviewed

    Masashi Kurosawa, Akio Ohta, Masaaki Araidai, Shigeaki Zaima

    Japanese Journal of Applied Physics   Vol. 55 ( 8 ) page: 08NB07   2016.7

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  47. Origin of the unidentified positive mobile ions causing the bias temperature instability in SiC MOSFETs and their diffusion process Reviewed

    Shirakawa, H., Kamiya, K., Araidai, M., Watanabe, H., Shiraishi, K.

    Applied Physics Express   Vol. 9 ( 6 ) page: 64301 - 64301   2016.6

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    © 2016 The Japan Society of Applied Physics. For SiC metal-oxide-semiconductor field-effect transistors (MOSFETs), it has been shown that unidentified positive mobile ions are generated in SiO2 after conventional hydrogen annealing, which leads to significant reliability degradation known as bias temperature instability (BTI). Discovering the origin of these mobile ions is important for fabricating highly reliable SiC MOSFETs. On the basis of first-principles calculations, we verified that the BTI of SiC MOSFETs is caused by hydrogen ions combining with CO3-like defects in SiO2. These hydrogen ions dissociate from the CO3-like defects and diffuse "as protons" in SiO2. These results indicate that the observed positive mobile ions are protons.

    DOI: 10.7567/APEX.9.064301

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  48. Si1–xSnx半導体のエネルギーバンド構造に関する理論的および実験的分析

    長江祐樹, 柴山茂久, 黒澤昌志, 洗平昌晃, 中塚理, 白石賢二, 財満鎭明

    電子デバイス界面テクノロジー研究会(第21回)     page: pp. 17-20   2016.1

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  49. Theoretical Investigation on Electronic and Magnetic Structures of FeRh Reviewed

    Takahashi Hidekazu, Araidai Masaaki, Okada Susumu, Shiraishi Kenji

    Journal of the Magnetics Society of Japan   Vol. 40 ( 4 ) page: 77 - 80   2016

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    In order to clarify the mechanism behind antiferromagnetic (AFM)-ferromagnetic (FM) phase transition, we investigate the electronic and magnetic structures of FeRh by using first principles calculations with the GGA + <i>U</i> method. By choosing the appropriate values of the on-site Coulomb interaction (<i>U</i>) of Fe<sub>3d</sub> and Rh<sub>4d</sub> electrons, we succeed in explaining the reported AFM-FM phase transition experiments for the first time by obtaining the total energy difference between the AFM and FM states (Δ<i>E</i>). Other physical quantities such as the density of states (DOS) are also consistent with experimental reports.

    DOI: 10.3379/msjmag.1605L011

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  50. First principles study on the strain dependence of thermal oxidation and hydrogen annealing effect at Si/SiO<inf>2</inf> interface in V-MOSFET Reviewed

    Shingo Kawachi, Hiroki Shirakawa, Masaaki Araidai, Hiroyuki Kageshima, Tetsuo Endoh, Kenji Shiraishi

    ECS Transactions   Vol. 75 ( 5 ) page: 293 - 299   2016

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    © 2016 The Electrochemical Society. Gate insulator of vertical MOSFET (V-MOSFET) is formed by silicon oxide. However, Si pillar cannot keep the structure during oxidation process because the Si atoms disappear from bulk (missing-Si). Moreover, the effect of hydrogen annealing for VMOSFET under the typical condition becomes weaker than that for planer MOSFET. In this study, we revealed the physical origin of missing-Si and hydrogen annealing effects by using first principles calculation method. We considered that the strain which is accumulated at the Si/SiO2 interface in V-MOSFET due to pillar structures. In this study, we clarified the strain dependence of thermal oxidation of V-MOSFET based on the Si-emission model [1,2]. The obtained results indicate that the compressive strain is one of the causes of the missing-Si. Furthermore, we investigated the strain dependence of the effect of hydrogen annealing. As a result, we revealed that hydrogen annealing temperature of VMOSFET should be lower than that of planer-MOSFET.

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  51. Ultrathin Si or Ge Films on Ag Formed by Metal-Induced Layer Exchange Method:&mdash;A First Step Towards Creation of Silicene and Germanene&mdash; Invited Reviewed

    KUROSAWA Masashi, OHTA Akio, ARAIDAI Masaaki, ZAIMA Shigeaki

    Hyomen Kagaku   Vol. 37 ( 8 ) page: 374 - 379   2016

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    <p>Two-dimensional (2D) honeycomb sheet of Si and Ge, known as silicene and germanene, respectively, is a promising material for next-generation group-IV electronics. Most researchers have synthesized them by deposition of Si or Ge atoms on metal substrates. On the other hand, this paper proposes a unique technique for synthesizing these 2D honeycomb sheets on Ag-covered Si or Ge substrate by using Ag-induced layer exchange (ALEX) process. Our method enables surface segregation of Si or Ge atoms from the underlying substrate by tuning annealing condition during ALEX. We believe that the present study is a first step towards creation of 2D honeycomb sheets on a Si chip.</p>

    DOI: 10.1380/jsssj.37.374

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  52. Chemical synthesis of group-IV nanosheets from layered compounds Reviewed

    Asaeda Shungo, Kurosawa Masashi, Ohta Akio, Araidai Masaaki, Zaima Shigeaki

    Abstract of annual meeting of the Surface Science of Japan   Vol. 36 ( 0 ) page: 174 - 174   2016

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    DOI: 10.14886/sssj2008.36.0_174

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  53. First-Principles Study on Hydrogen Annealing Effect in Si/SiO2 Interface by Thermal Oxidation Reviewed

    S. Kawachi, H. Hiroki, M. Araidai, H. Kageshima, T.Endoh, K.Shiraishi

    2015 International Conference on Solid State Devices and Materials(SSDM)   Vol. PS-1-17   page: 40 - 41   2015.9

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  54. A 50-nm 1.2-V Ge<inf>x</inf>Te<inf>1-x</inf>/Sb<inf>2</inf>Te<inf>3</inf> superlattice topological-switching random-access memory (TRAM) Reviewed

    M. Tai, T. Ohyanagi, M. Kinoshita, T. Morikawa, K. Akita, M. Takato, H. Shirakawa, M. Araidai, K. Shiraishi, N. Takaura

    Digest of Technical Papers - Symposium on VLSI Technology   Vol. 2015-August   page: T96 - T97   2015.8

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    © 2015 JSAP. A 50nm topological-switching random-access memory (TRAM) was fabricated for the first time. A high-quality GexTe1-x/Sb2Te3 superlattice film enabled set and reset voltages of TRAM to be less than 40% of those of PRAM. Statistical analysis of 16kb data showed the reset voltage to be less than 1.2 V, the lowest as a TRAM test chip.

    DOI: 10.1109/VLSIT.2015.7223707

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  55. First principles study of SiC/SiO<inf>2</inf> interfaces towards future power devices Reviewed

    K. Shiraishi, K. Chokawa, H. Shirakawa, K. Endo, M. Araidai, K. Kamiya, H. Watanabe

    Technical Digest - International Electron Devices Meeting, IEDM   Vol. 2015-February ( February ) page: 21.3.1 - 21.3.4   2015.2

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    © 2014 IEEE. We clarify the intrinsic problems of SiC/SiO2 interfaces by the first principles calculations. The unique nearly free electron like characteristics of SiC conduction band bottom causes unexpected formation of interface states near the conduction band bottoms by process induced strain. These results indicate that strain free process is necessary for fabricating high quality NMOSFET. Another proposal is developing PMOSFET instead of presently popular NMOSFET. Moreover, we also discuss the Vth instability caused by proton diffusion.

    DOI: 10.1109/IEDM.2014.7047095

    Scopus

  56. 55-μA Ge<inf>x</inf>Te<inf>1-x</inf>/Sb<inf>2</inf>Te<inf>3</inf> superlattice topological-switching random access memory (TRAM) and study of atomic arrangement in Ge-Te and Sb-Te structures Reviewed

    N. Takaura, T. Ohyanagi, M. Tai, M. Kinoshita, K. Akita, T. Morikawa, H. Shirakawa, M. Araidai, K. Shiraishi, Y. Saito, J. Tominaga

    Technical Digest - International Electron Devices Meeting, IEDM   Vol. 2015-February ( February ) page: 29.2.1 - 29.2.4   2015.2

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    © 2014 IEEE. GexTe1-x/Sb2Te3 superlattice topological-switching random access memory (TRAM) was developed. Set and reset currents of 55 μA, the lowest for an ULSI-grade device, were obtained. TEM analyses of the Ge-Te structures and novel superlattice fabrication enabled us to reveal the retention, endurance, and electrical characteristics of TRAM for the first time.

    DOI: 10.1109/IEDM.2014.7047132

    Scopus

  57. A 50-nm 1.2-V GexTe1-x/Sb2Te3 superlattice topological-switching random-access memory (TRAM)

    Tai M., Ohyanagi T., Kinoshita M., Morikawa T., Akita K., Takato M., Shirakawa H., Araidai M., Shiraishi K., Takaura N.

    2015 SYMPOSIUM ON VLSI TECHNOLOGY (VLSI TECHNOLOGY)     page: .   2015

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  58. XRD analysis of TRAM composed from [Sb<inf>2</inf>Te3/GeTe] superlattice film and its switching characteristics Reviewed

    T. Ohyanagi, M. Kitamura, S. Kato, M. Araidai, N. Takaura, K. Shiraishi

    Materials Research Society Symposium Proceedings   Vol. 1729   page: 41 - 45   2015

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    © 2015 Materials Research Society. We studied GeTe structures in topological switching random access memories (TRAMs) with a [GeTe/Sb2Te3] superlattice by using X-ray diffraction (XRD) analysis. We examined the electrical characteristics of the TRAMs deposited at different temperatures. We found that XRD spectra differed between the films deposited at 200 and 240°C and that the differences corresponded to the differences in the GeTe sequences in the films.

    DOI: 10.1557/opl.2015.170

    Scopus

  59. 1T-1R pillar-type topological-switching random access memory (TRAM) and data retention of GeTe/Sb<inf>2</inf>Te<inf>3</inf> super-lattice films Reviewed

    M. Tai, T. Ohyanagi, M. Kinoshita, T. Morikawa, K. Akita, S. Kato, H. Shirakawa, M. Araidai, K. Shiraishi, N. Takaura

    Digest of Technical Papers - Symposium on VLSI Technology     page: 1-2   2014.9

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    © 2014 IEEE. A 1T-1R pillar-type 'topological-switching RAM' (TRAM) and the data retention of GeTe/Sb2Te3 super-lattice were investigated. Reset voltage of TRAM, 2 V, was 40 % of that of the conventional PCM with Ge2Sb2Te5. From data retention evaluation, the TRAM was found to endure the retention at 260 °C for 18 hours.

    DOI: 10.1109/VLSIT.2014.6894436

    Scopus

  60. GeTe sequences in superlattice phase change memories and their electrical characteristics Reviewed

    Ohyanagi, T., Kitamura, M., Araidai, M., Kato, S., Takaura, N., Shiraishi, K.

    Applied Physics Letters   Vol. 104 ( 25 ) page: 252106(1)-(3)   2014.6

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    ©2014 AIP Publishing LLC. We studied GeTe structures in superlattice phase change memories (superlattice PCMs) with a [GeTe/Sb2Te3.O stacked structure by X-ray diffraction (XRD) analysis. We examined the electrical characteristics of superlattice PCMs with films deposited at different temperatures. It was found that XRD spectra differed between the films deposited at 2<X) C and 240 °C; the differences corresponded to the differences in the GeTe sequences in the films. We applied first-principles calculations to calculate the total energy of three different GeTe sequences. The results showed the Ge-Te-Ge-Te sequence had the lowest total energy of the three and it was found that with this sequence the superlattice PCMs did not run.

    DOI: 10.1063/1.4886119

    Web of Science

    Scopus

  61. Asymmetric behavior of current-induced magnetization switching in a magnetic tunnel junction: Non-equilibrium first-principles calculations Reviewed

    Araidai, M., Yamamoto, T., Shiraishi, K.

    Applied Physics Express   Vol. 7 ( 4 ) page: 45202 - 45202   2014.4

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    We investigated the microscopic mechanisms of current-induced magnetization switching (CIMS) in an Fe/MgO(001)/Fe/Ta magnetic tunnel junction using non-equilibrium first-principles calculations. We found that the change in the magnetization configuration from antiparallel (AP) to parallel (P) can be realized with a lower electrical power than that from P to AP. From detailed analyses of the density of states subject to a finite bias voltage, we clarified that the asymmetric behavior originates from the difference in the electron scattering processes between switching directions. © 2014 The Japan Society of Applied Physics.

    DOI: 10.7567/APEX.7.045202

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    CiNii Article

  62. Understanding the switching mechanism of charge-injection GeTe/Sb <inf>2</inf>Te<inf>3</inf> phase change memory through electrical measurement and analysis of 1R test structure Reviewed

    N. Takaura, T. Ohyanagi, M. Tai, M. Kitamura, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    IEEE International Conference on Microelectronic Test Structures     page: 32 - 37   2014

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    We describe the switching mechanism of GeTe/Sb2Te3 phase change memory called "topological-switching Random Access Memory" (TRAM). DC sweep and AC transient analysis of the TRAM TEGs provided evidence of enhancement of atomic movement in TRAM by charge injection. A hysteresis loop of resistance that was characteristic to TRAM, fast threshold switching of 4 ns by electron injection, and MLC capabilities by hole generation were revealed for the first time. © 2014 IEEE.

    DOI: 10.1109/ICMTS.2014.6841464

    Scopus

  63. 55-mu A GexTe1-x/Sb2Te3 superlattice topological-switching random access memory ( TRAM) and study of atomic arrangement in Ge-Te and Sb-Te structures

    Takaura N., Ohyanagi T., Tai M., Kinoshita M., Akita K., Morikawa T., Shirakawa H., Araidai M., Shiraishi K., Saito Y., Tominaga J.

    2014 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM)     page: .   2014

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    Web of Science

  64. First Principles Study of SiC/SiO2 Interfaces towards Future Power Devices

    Shiraishi K., Chokawa K., Shirakawa H., Endo K., Araidai M., Kamiya K., Watanabe H.

    2014 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM)     page: .   2014

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    Web of Science

  65. 1T-1R Pillar-Type Topological-switching Random Access Memory (TRAM) and Data Retention of GeTe/Sb2Te3 Super-Lattice Films

    Tai M., Ohyanagi T., Kinoshita M., Morikawa T., Akita K., Kato S., Shirakawa H., Araidai M., Shiraishi K., Takaura N.

    2014 SYMPOSIUM ON VLSI TECHNOLOGY (VLSI-TECHNOLOGY): DIGEST OF TECHNICAL PAPERS     2014

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  66. 55-mu A GexTe1-x/Sb2Te3 superlattice topological-switching random access memory ( TRAM) and study of atomic arrangement in Ge-Te and Sb-Te structures

    Takaura N, Ohyanagi T, Tai M, Kinoshita M, Akita K, Morikawa T, Shirakawa H, Araidai M, Shiraishi K, Saito Y, Tominaga J

    2014 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM)     page: .   2014

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  67. Understanding the Switching Mechanism of Charge-Injection GeTe/Sb2Te3 Phase Change Memory through Electrical Measurement and Analysis of 1R Test Structure

    Takaura N., Ohyanagi T., Tai M., Kitamura M., Kinoshita M., Akita K., Morikawa T., Kato S., Araidai M., Kamiya K., Yamamoto T., Shiraishi K.

    2014 IEEE INTERNATIONAL CONFERENCE ON MICROELECTRONIC TEST STRUCTURES (ICMTS)     page: 32 - 37   2014

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  68. Charge-injection phase change memory with high-quality GeTe/Sb <inf>2</inf>Te<inf>3</inf> superlattice featuring 70-μA RESET, 10-ns SET and 100M endurance cycles operations Reviewed

    T. Ohyanagi, N. Takaura, M. Tai, M. Kitamura, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    Technical Digest - International Electron Devices Meeting, IEDM     page: 30.5.1-30.5.4   2013

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    We developed a high quality charge-injection GeTe/Sb2Te 3 superlattice phase change memory. A RESET-current of 70 μA and a SET-speed of 10 ns, the fastest ever reported, were obtained. Transmission electron microscopy analysis showed that the superlattice structure was maintained after 1 million (M) endurance. Even 100 M cycle endurance was possible, and these results conclusively proved non-melting resistive switching. © 2013 IEEE.

    DOI: 10.1109/IEDM.2013.6724725

    Scopus

  69. Charge-Injection Phase Change Memory with High-Quality GeTe/Sb2Te3 Super lattice Featuring 70-mu A RESET, 10-ns SET and 100M Endurance Cycles Operations

    Ohyanagi T., Takaura N., Tai M., Kitamura M., Kinoshita M., Akita K., Morikawa T., Kato S., Araidai M., Kamiya K., Yamamoto T., Shiraishi K.

    2013 IEEE INTERNATIONAL ELECTRON DEVICES MEETING (IEDM)     2013

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  70. Single-atom electromigration in atomic-scale conductors Reviewed

    Araidai, M., Tsukada, M.

    Fundamentals of Picoscience     page: 529 - 540   2013

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    © 2014 by Taylor & Francis Group, LLC. Electromigration is the directed migration of atoms caused by electric currents, and it is well known as a major failure mechanism in the operation of electronic devices. So far, many researches have been done both experimentally and theoretically [1,2]. Traditionally, the origin of electromigration has been discussed in terms of electrostatic forces and momentum transfers by electrons to atoms in current flow. The latter is often called as “electron wind force,” which is a characteristic force in electromigration. Joule heating around the migrating atoms is also one of the most important factors because it facilitates the atomic diffusions.

    DOI: 10.1201/b15523

    Scopus

  71. Charge injection Super-lattice Phase Change Memory for low power and high density storage device applications Reviewed

    N. Takaura, T. Ohyanagi, M. Kitamura, M. Tai, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    Digest of Technical Papers - Symposium on VLSI Technology     2013

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    A new charge injection Super-lattice Phase Change Memory was developed with optimized GeTe/Sb2Te3 deposition and state-of-the-art analytical techniques. First principle calculations showed the charge injection enhanced Ge atom movement for the first time. We achieved 0.46 V and 3.3 MA/cm2 reset and MLC programming. The stability of Super-lattice after 1E6 cycles was verified by thermal analysis characteristic to Ge 4-fold to Ge 6-fold transition. © 2013 JSAP.

    Scopus

  72. Origin of nanomechanical motion in a single-C-60 transistor Reviewed

    Ikutaro Hamada, Masaaki Araidai, Masaru Tsukada

    PHYSICAL REVIEW B   Vol. 85 ( 12 ) page: 121401(1)-121401(4)   2012.3

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    We present a van der Waals density functional study of a negatively charged C-60 on a Au(111) surface to investigate the nanomechanical motion in a single-molecular transistor [Park et al., Nature 407, 57 (2000)]. We found that the position of C-60 is shifted away from the electrode surface when C-60 is negatively charged because of the larger contribution from the Pauli repulsion between C-60(-) and substrate than that from the attractive interaction with the image charge induced in the substrate. Implication to the Franck-Condon blockade is also discussed.

    DOI: 10.1103/PhysRevB.85.121401

    Web of Science

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  73. Nonadiabatic electromigration along a one-dimensional gold chain Reviewed

    Araidai, M., Tsukada, M.

    Physical Review B - Condensed Matter and Materials Physics   Vol. 84 ( 19 ) page: 195461(1)-195461(5)   2011.11

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    We have investigated nonadiabatic processes of electromigration by theoretical calculation, taking the example of a gold atom moving along a chain of gold atoms. The calculated electromigration rate showed almost linear behavior beyond a threshold and rapidly increased with increasing applied bias voltage. It was found from the detailed analysis that the electronic scattering takes place via the d orbitals of a migrating Au atom with larger lobes in the migration direction, accompanied by an excitation of the atom vibration from the ground state to a continuum state, leading to nonadiabatic electromigration. Through a comparison of the electromigration rates between nonadiabatic and thermal migration, we clarified that the nonadiabatic contribution is dominant at low temperature and low bias beyond the threshold voltage. © 2011 American Physical Society.

    DOI: 10.1103/PhysRevB.84.195461

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  74. Composition dependence of magnetoresistance effect and its annealing endurance in tunnel junctions having Mn-Ga electrode with high perpendicular magnetic anisotropy Reviewed

    Kubota, T., Araidai, M., Mizukami, S., Zhang, X., Ma, Q., Naganuma, H., Oogane, M., Ando, Y., Tsukada, M., Miyazaki, T.

    Applied Physics Letters   Vol. 99 ( 19 ) page: 192509(1)-192509(3)   2011.11

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    The composition dependence of the tunnel magnetoresistance (TMR) effect in Mn-Ga/MgO/CoFe magnetic tunnel junctions (MTJs) for Mn54Ga 46, Mn62Ga38, and Mn71Ga 29 (at. %) electrodes was investigated. An MTJ with a Mn 62Ga38 electrode showed a maximum TMR ratio of 23% at 10 K and high annealing endurance up to 375 °C. The bias voltage dependence of the TMR ratio was distinct among MTJs with different Mn-Ga compositions. Here, we discuss this dependence on the basis of the difference in the Δ1 band dispersions for Mn-Ga alloys calculated by first principles. © 2011 American Institute of Physics.

    DOI: 10.1063/1.3659484

    Web of Science

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  75. Theoretical calculations of electron transport in molecular junctions: Inflection behavior in Fowler-Nordheim plot and its origin Reviewed

    Araidai, M., Tsukada, M.

    Physical Review B - Condensed Matter and Materials Physics   Vol. 81 ( 23 ) page: 235114(1)-235114(7)   2010.6

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    We investigated the origin of an inflection behavior appearing in Fowler-Nordheim (F-N) plot of current-voltage characteristics for molecular junctions using two different levels of calculation methods: nonequilibrium Green's-function technique combined with the density-functional theory and tight-binding approximation. Although the inflection has so far been interpreted from the naive model that the charge transport mechanism transits from a direct to the F-N tunneling, our results indicated that the inflection does not necessarily mean the transition between the two regimes. We found from the close examination of the relation between the behavior of the F-N curve and the transmission function that the inflection takes place when the molecular level responsible for electric currents approaches to the edge of the bias window. While our interpretation for the inflection drastically differ from the conventional model, the F-N plots obtained from our calculations showed closely similar behavior as those from the recent experiments. © 2010 The American Physical Society.

    DOI: 10.1103/PhysRevB.81.235114

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  76. Field Emission from Graphitic Nanostructures Reviewed

    Watanabe, K., Araidai, M.

    Carbon Nanotube and Related Field Emitters: Fundamentals and Applications     page: 55 - 66   2010

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    DOI: 10.1002/9783527630615.ch5

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  77. Diffusion processes in single-atom electromigration along a gold chain: First-principles calculations Reviewed

    Araidai, M., Tsukada, M.

    Physical Review B - Condensed Matter and Materials Physics   Vol. 80 ( 4 ) page: 045417(1)-045417(5)   2009.7

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    Electromigration of a single atom along a chain of gold atoms was investigated by first-principles calculations based on the nonequilibrium Green's-function technique combined with density-functional theory. In the case of electromigration of a gold atom, we found that the potential barrier along the migration pathway decreases as the applied bias voltage is increased and the migration direction is the same as that of electron flow. By considering the case of electromigration of a sulfur atom along the gold chain, we determined that the electron flow around the migrating atom is responsible for single-atom electromigration. The calculated electromigration rate for the gold atom indicated that the electromigration takes place at temperatures above room temperature. © 2009 The American Physical Society.

    DOI: 10.1103/PhysRevB.80.045417

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  78. Ab initio calculation of surface atom evaporation in electron field emission Reviewed

    Araidai, M., Watanabe, K.

    e-Journal of Surface Science and Nanotechnology   Vol. 5 ( 5 ) page: 106 - 109   2007

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Surface Science Society of Japan  

    Surface atom evaporation under electron field emission was investigated by scattering-state calculations based on the density-functional theory. We found that surface atom evaporation assisted by electron field emission occurs for a certain electric-field strength that is lower than that of usual field evaporation without electron field emission. The present ab-initio study elucidates the surface atom process under field emission, which has been frequently observed in experiments, for the first time. © 2007 The Surface Science Society of Japan.

    DOI: 10.1380/ejssnt.2007.106

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    CiNii Article

  79. Comparative study of time-dependent and scattering-state ab initio calculations for field emission Reviewed

    Araidai, M., Souma, S., Watanabe, K.

    e-Journal of Surface Science and Nanotechnology   Vol. 3 ( 3 ) page: 457 - 460   2005

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:The Surface Science Society of Japan  

    We perform time-dependent (TD) and scattering-state (SS) ab-inito calculations for simulating the field emission (FE) of Na surfaces to explore the applicability of the two schemes. The amplitude of emission current is evaluated more reliably by SS than TD methods, because the former treats the steady-state electron tunneling faithfully but the latter utilizes transient electron dynamics. In contrast with the evaluation of current amplitude, the TD method is more suitable than the SS one for revealing the electronic-state origin of FE, because the TD method can directly determine the time evolution of all wave functions caused by an electric field. Thus, the TD and SS methods are found to play a complementary role in the FE study. © 2005 The Surface Science Society of Japan.

    DOI: 10.1380/ejssnt.2005.457

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    CiNii Article

  80. Field emission mechanisms of graphitic nanostructures Reviewed

    Araidai, M., Nakamura, Y., Watanabe, K.

    Physical Review B - Condensed Matter and Materials Physics   Vol. 70 ( 24 ) page: 245410(1)-245410(5)   2004.12

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    Field emission (FE) and the electronic-states origin of graphitic
    nanostructures were investigated by first-principles calculations based on
    time-dependent density-functional theory. We find that the FE current from
    graphitic ribbons changes remarkably depending on the hydrogen termination and
    the direction of the applied electric field. Also, the FE current from graphene
    sheets shows a dramatic increase around vacancy defects. We verified, through
    the analysis of local electronic structures and energy distributions of emitted
    electrons, that the dangling-bond (or $\sigma$) character is responsible for
    these results and governs the nature of the FE of graphitic nanostructures.

    DOI: 10.1103/PhysRevB.70.245410

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    arXiv

  81. Ab initio study of field emission from hydrogen defects in diamond subsurfaces Reviewed

    Araidai, M., Watanabe, K.

    Applied Surface Science   Vol. 237 ( 1-4 ) page: 482 - 487   2004.10

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    The field-emission (FE) of diamond surfaces with hydrogen defects in the subsurface is investigated by time-dependent density-functional theory calculation. It is found that FE currents from diamond surface with hydrogen atoms in the subsurface region are significantly enhanced because the defect levels induced by the hydrogen atoms in the energy band gap have small ionization energy. The shapes of energy distribution of FE current density vary largely depending on the type of hydrogen defects. The present results suggest that high emission current from diamond surfaces at low electric fields observed in experiments is ascribed to hydrogen defects in diamond subsurfaces. © 2004 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.apsusc.2004.07.029

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  82. Field emission and electronic structures of carbon allotropes Reviewed

    Watanabe, K., Araidai, M., Tada, K.

    Thin Solid Films   Vol. 464   page: 354 - 359   2004.10

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    Field emissions (FEs) of a carbon atom, silicon clusters, graphitic ribbons and diamond surfaces have been investigated within the time-dependent density-functional theory (TD-DFT). The electronic states origin of field emission properties reflecting the atomic geometries and hydrogen (H) termination of edges are elucidated through the analyses of energy band structures, energy distribution of emitted electrons and σ- and π-bonding natures. Findings in this study provide the theoretical basis for understanding the FE mechanism of covalent-bond materials and designing Si- and C-based nanostructured field emitters. © 2004 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.tsf.2004.06.048

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  83. Time-Dependent Density-Functional Calculations of Field Emissions from Carbon Allotropes Invited Reviewed

    Kazuyuki Watanabe, Masaaki Araidai, Kazuhiro Tada, Akihiro Yamauchi

    Transactions of the Materials Research Society of Japan   Vol. 29 ( 6 ) page: 3681-3685   2004.9

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  84. Time-Dependent Density-Functional Calculations of Field Emissions from Carbon Allotropes Invited Reviewed

    Kazuyuki Watanabe, Masaaki Araidai, Kazuhiro Tada, Akihiro Yamauchi

    Transactions of the Materials Research Society of Japan   Vol. 29 ( 6 ) page: 3681-3685   2004.9

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  85. Electronic States Origin of Field Emission of Silicon Clusters Reviewed

    Araidai, M., Yamauchi, A., Watanabe, K.

    Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers   Vol. 42 ( 10 ) page: 6502 - 6503   2003.10

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    The electronic states origin of the field emission of silicon clusters as a model system of covalent-bond nanostructures is elucidated by time-dependent density-functional calculations. The local electronic properties, σ - or π-bonding states of silicon clusters, are crucial for understanding the field emission characteristics. The findings in this study provide a theoretical basis for understanding and designing Si - and C-based nanostructured field emitters.

    DOI: 10.1143/JJAP.42.6502

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    CiNii Article

    CiNii Books

  86. Field emission of diamond surfaces by time-dependent density-functional calculations Reviewed

    Araidai, M., Watanabe, K.

    Japanese Journal of Applied Physics, Part 2: Letters   Vol. 42 ( 6B ) page: L666 - L668   2003.6

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    The electron field emission (FE) of diamond C(100) 2 × 1 surfaces has been investigated using time-dependent density-functional calculations. Dangling-bond (DB) states are found to be the main source of FE current of a clean surface. Notwithstanding the disappearance of the DB states by hydrogen (H) termination of a surface, FE current increases compared with that from the clean surface. An important finding from a comparison with the FE of graphitic ribbons is that the electronic structures being influenced by either carbon atom geometry or H termination govern the microscopic mechanism of the FE of carbon materials.

    DOI: 10.1143/JJAP.42.L666

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    CiNii Article

    CiNii Books

  87. Ab initio study of field emission from atomic-scale surfaces

    Watanabe K, Watanabe S, Araidai M, Gohda Y

    TECHNICAL DIGEST OF THE 16TH INTERNATIONAL VACUUM MICROELECTRONICS CONFERENCE     page: 1 - 2   2003

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  88. Ab initio study of field emission from atomic-scale surfaces Reviewed

    K. Watanabe, S. Watanabe, M. Araidai, Y. Gohda

    Proceedings of the IEEE International Vacuum Microelectronics Conference, IVMC   Vol. 2003-January   page: 1 - 2   2003

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    DOI: 10.1109/IVMC.2003.1222940

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Books 1

  1. ポストグラフェン材料の創製と用途開発最前線 ~二次元ナノシートの物性評価、構造解析、合成、成膜プロセス技術、応用展開~

    洗平昌晃( Role: Contributor ,  計算科学によるIV族二次元物質の研究)

    (株)エヌ・ティー・エス  2020.4  ( ISBN:978-4-86043-657-5

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    Total pages:448   Responsible for pages:51-58   Language:Japanese Book type:Scholarly book

Presentations 154

  1. Multicanonical simulations with physically informed neural network potentials on chemical reactions in gas phase International conference

    Masaaki Araidai

    The 8th Asian Conference on Crystal Growth and Crystal Technology  2021.3.2 

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    Event date: 2021.3

    Language:English   Presentation type:Oral presentation (general)  

  2. ab initio計算を用いたGaN MOVPEにおけるTMG分解過程へのH2とNH3による効果の理論的考察

    榊原聡真,長川健太,洗平昌晃,草場 彰,寒川 義裕,白石賢二

    第26回 電子デバイス界面テクノロジー研究会  2021.1.23 

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    Event date: 2021.1

    Language:Japanese   Presentation type:Oral presentation (general)  

  3. K イオンエレクトレットの負電荷蓄積機構及び作製指針の理論的検討

    中西徹, 長川健太, 洗平昌晃, 年吉洋, 杉山達彦, 橋口原, 白石賢二

    第26回電子デバイス界面テクノロジー研究会  2021.1.23 

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    Event date: 2021.1

    Language:Japanese   Presentation type:Oral presentation (general)  

  4. Fe/MgO 界面への窒素不純物が磁気異方性と TMR に与える影響について

    小川湧太郎, 洗平昌晃, 遠藤哲郎, 白石賢二

    第26回電子デバイス界面テクノロジー研究会  2021.1.22 

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    Event date: 2021.1

    Language:Japanese   Presentation type:Oral presentation (general)  

  5. Theoretical study of the effects of H2 and NH3 on the TMG decomposition process in GaN crystal growth International conference

    S. Sakakibara, K. Chokawa, M. Araidai, A. Kusaba, Y. Kangawa, K. Shiraishi

    The International Symposium on Wide Gap Semiconductor Growth, Process and Device Simulation 2021  2021.1.20 

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    Event date: 2021.1

    Language:English   Presentation type:Poster presentation  

  6. Effect of Nitrogen Impurity Atoms at Fe/MgO Interface on Perpendicular Magnetic Anisotropy Energy International conference

    Y. Ogawa, M. Araidai, T. Endoh, and K. Shiraishi

    51st IEEE Semiconductor Interface Specialists Conference  2020.12.18 

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    Event date: 2020.12

    Language:English   Presentation type:Poster presentation  

  7. GaN MOVPEにおけるTMG分解過程へのH2とNH3による効果の理論的考察

    榊原聡真, 長川健太, 洗平昌晃, 草場 彰, 寒川義裕, 白石賢二

    第49回日本結晶成長国内学会  2020.11.9 

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    Event date: 2020.11

    Language:Japanese   Presentation type:Oral presentation (general)  

  8. カリウムイオンエレクトレットにおける負電荷蓄積機構の第一原理計算による検討

    中⻄徹, 宮島岳史, ⻑川健太, 洗平昌晃, 杉山達彦, 橋口原, 白石賢二

    第37回「センサ・マイクロマシンと応用システム」シンポジウム  2020.10.27 

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    Event date: 2020.10

    Language:Japanese   Presentation type:Oral presentation (general)  

  9. 帯電が誘起する強誘電直方晶HfO2薄膜の安定性:第一原理計算による検討

    新井千慧, 白石悠人, 洗平昌晃, 白石賢二, 中山隆史

    第81回応用物理学会秋季学術講演会  2020.9.10 

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    Event date: 2020.9

    Language:Japanese   Presentation type:Oral presentation (general)  

  10. 多層ゲルマナンフレークからの水素脱離

    伊藤麻維, 洗平昌晃, 大田晃生, 中塚理, 黒澤昌志

    第81回応用物理学会秋季学術講演会  2020.9.9 

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    Event date: 2020.9

    Language:Japanese   Presentation type:Oral presentation (general)  

  11. ab initio計算を用いたGaN MOVPE成長におけるTMGa分解反応の探索

    榊原聡真, 洗平昌晃, 叶正, 新田州吾, 本田善央, 天野浩, 白石賢二

    第81回 応用物理学会秋季学術講演会  2020.9.8 

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    Event date: 2020.9

    Language:Japanese   Presentation type:Oral presentation (general)  

  12. MgOを用いたMgドープGaNのHVPE成長における気相反応の熱力学的解析

    木村友哉, 大西一生, 天野裕己, 藤元直樹, 洗平昌晃, 新田州吾, 本田善央, 天野浩, 寒川義裕, 白石賢二

    日本結晶成長学会ナノエピ分科会「第12回ナノ構造・エピタキシャル成長講演会」  2020.7.31 

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    Event date: 2020.7

    Language:Japanese   Presentation type:Oral presentation (general)  

  13. 超格子GeTe/Sb₂Te₃メモリの第一原理計算による構造変化シミュレーション

    小川 湧太郎, 野原 弘晶, 白川 裕規, 洗平 昌晃, 白石 賢二

    電子情報通信学会 

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    Event date: 2019.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  14. Formation of Ultrathin Segregated-Ge Crystal on Al/Ge(111) Surface by Thermal Annealing

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    Event date: 2019.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  15. Neural network potential for Si/SiO<sub>2</sub> interface

    Mataka M., Araidai M., Nagura T., Shiraishi K.

    The Physical Society of Japan 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  16. The electric field effect and the dependence of nanoribbon width in monolayer nanoribbons of IV group materials

    Hattori Ayami, Yada Keiji, Araidai Masaaki, Tanaka Yukio

    The Physical Society of Japan 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  17. Two-dimensional structure of Ge atoms segregated on Ag(111)

    Shimazu Hiroki, Yuhara Junji, Nakatake Masashi, Ito Kouichi, Ohta Akio, Araidai Masaaki, Kurosawa Masashi

    The Physical Society of Japan 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

    CiNii Article

  18. 第一原理計算による超格子GeTe/Sb₂Te₃相変化メモリの理論的検討

    野原 弘晶, 白川 裕規, 洗平 昌晃, 白石 賢二

    電子情報通信学会 

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    Event date: 2018.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  19. First-principles study on hydrogen absorption and desorption of germanene

    Araidai Masaaki, Kurosawa Masashi, Ohta Akio, Shiraishi Kenji

    The Physical Society of Japan 

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    Event date: 2018.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  20. Edge magnetization and an electric field effect in monolayer nanoribbons of IV group materials

    Hattori Ayami, Araidai Masaaki, Tanaka Yukio

    The Physical Society of Japan 

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    Event date: 2018.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  21. Multi-Physics Simulation of GaN MOVPE Growth

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    Event date: 2017.11

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Country:Japan  

    CiNii Article

  22. エピタキシャルAg(111)上の極薄Ⅳ族結晶形成

    伊藤 公一, 大田 晃生, 黒澤 昌志, 洗平 昌晃, 池田 弥央, 牧原 克典, 宮崎 誠一

    電子情報通信学会 

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    Event date: 2017.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  23. Electronic states of two-dimensional crystals of group IV element on amorphous insulating films

    Araidai Masaaki, Kurosawa Masashi, Ohta Akio, Shiraishi Kenji

    The Physical Society of Japan 

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    Event date: 2017.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  24. Control of Chemical Reaction between Ag Thin Film and Group-IV Semiconductors

    Ito Koichi, Akio Ohta, Kurosawa Masashi, Araidai Masaaki, Ikeda Mitsuhisa, Makihara Katsunori, Miyazaki Seiichi

    The Surface Science Society of Japan 

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    Event date: 2016.11 - 2016.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  25. Chemical synthesis of group-IV nanosheets from layered compounds

    Asaeda Shungo, Kurosawa Masashi, Ohta Akio, Araidai Masaaki, Zaima Shigeaki

    The Surface Science Society of Japan 

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    Event date: 2016.11 - 2016.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  26. Electronic states of germanene and stanene on Al<sub>2</sub>O<sub>3</sub> surfaces

    Araidai Masaaki, Kurosawa Masashi, Ohta Akio, Shiraishi Kenji

    The Physical Society of Japan 

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    Event date: 2016.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  27. Electric conduction properties in edge hydrogenated monolayer nanoribbons of group-IV materials

    Hattori Ayami, Araidai Masaaki, Tanaka Yukio

    The Physical Society of Japan 

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    Event date: 2016.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  28. Theoretical Studies on Electronic Structures of Silicene Ribbon and Silicene on Insulator International conference

    K. Shiraishi, A. Hattori, S. Tanaya, M. Araidai, A. Ohta, M. Kurosawa, Y. Hatsugai, M. Sato, and Y. Tanaka

    International Symposium on 2D Layered Materials and Art: Two Worlds Meet 

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    Event date: 2016.3

    Language:English   Presentation type:Oral presentation (invited, special)  

    Country:France  

  29. Edge states in hydrogenated silicene, germanene, stanene ribbons

    Hattori A., Araidai M., Hatsugai Y., Yada K., Shiraishi K., Sato M., Tanaka Y.

    The Physical Society of Japan 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  30. 水素終端シリセン、ゲルマネン、スタネンリボンにおけるエッジ状態

    服部綾実, 洗平昌晃, 初貝安弘, 矢田圭司, 白石賢二, 佐藤昌利, 田仲由喜夫

    日本物理学会 第71回年次大会(2016年) 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東北学院大学 泉キャンパス   Country:Japan  

  31. SiC/GaNの界面構造とバンドオフセットとの関係の理論的検討

    小嶋英嗣, 遠藤賢太郎, 白川裕規, 洗平昌晃, 海老原康裕, 金村高司, 恩田正一, 白石賢二

    第63回応用物理学会春季学術講演会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東工大 大岡山キャンパス   Country:Japan  

  32. V-MOSFETにおけるSi/SiO2(001)界面における熱酸化過程、水素アニール効果の歪み依存性の第一原理計算による考察

    川内伸悟, 白川裕規, 洗平昌晃, 影島博之, 遠藤哲郎, 白石賢二

    第63回応用物理学会春季学術講演会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東工大 大岡山キャンパス   Country:Japan  

  33. GaN結晶成長メカニズムの熱力学解析

    関口一樹, 白川裕規, 山本芳裕, 洗平昌晃, 白石賢二

    第63回応用物理学会春季学術講演会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東工大 大岡山キャンパス   Country:Japan  

  34. 絶縁膜上にあるIV族系二次元結晶の電子状態解析

    洗平昌晃, 黒澤昌志, 大田晃生, 白石賢二

    日本物理学会 第71回年次大会(2016年) 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東北学院大学 泉キャンパス   Country:Japan  

  35. First-principles study on two-dimensional crystals of group IV material on insulating film

    Araidai M., Kurosawa M., Ohta A., Shiraishi K.

    The Physical Society of Japan 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

    CiNii Article

  36. Characterization of Chemical Bonding Features of Ultrathin Ge Layer Grown by Ag-Induced Layer-Exchange Method International conference

    A. Ohta, M. Kurosawa, M. Araidai, S. Miyazaki

    8th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials / 9th International Conference on Plasma-Nano Technology & Science (ISPlasma2016/IC-PLANTS2016) 

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    Event date: 2016.3

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  37. Si1-xSnx半導体のエネルギーバンド構造に関する理論的および実験的分析

    長江祐樹, 柴山茂久, 黒澤昌志, 洗平昌晃, 中塚理, 白石賢二, 財満鎭明

    電子デバイス界面テクノロジー研究会(第21回) 

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    Event date: 2016.1

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東レ研修センター(静岡県三島市)   Country:Japan  

  38. Si/SiO2(100)界面における熱酸化過程、水素アニール効果の 歪み依存性に関する理論的研究

    川内伸悟, 白川裕規, 洗平昌晃, 影島愽之, 遠藤哲郎, 白石賢二

    電子デバイス界面テクノロジー研究会(第21回) 

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    Event date: 2016.1

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東レ研修センター(静岡県三島市)   Country:Japan  

  39. MONOSメモリにおけるSiO2膜中の窒素原子に起因する原子欠陥の理論的考察

    白川裕規, 洗平昌晃, 神谷克政, 白石賢二

    電子デバイス界面テクノロジー研究会(第21回) 

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    Event date: 2016.1

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東レ研修センター(静岡県三島市)   Country:Japan  

  40. Si and Ge Ultrathin Films by Ag-Induced Layer-Exchange Growth International conference

    M. Kurosawa, A. Ohta, M. Araidai, S. Zaima

    23rd International Colloquium on Scanning Probe Microscopy (ICSPM23) 

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    Event date: 2015.12

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  41. First-principles study on two-dimensional crystals of group IV element on insulating film International conference

    M. Araidai, M. Kurosawa, A. Ohta, K. Shiraishi

    23rd International Colloquium on Scanning Probe Microscopy (ICSPM23) 

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    Event date: 2015.12

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  42. First principles examination of the switching mechanism of the phase change memory (TRAM) using superlattice GeTe/Sb2Te3 International conference

    M. Takato, H. Shirakawa, M. Araidai, K. Shiraishi

    46th Semiconductor Interface Specialists Conference (SISC2015) 

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    Event date: 2015.12

    Language:English   Presentation type:Poster presentation  

    Country:United States  

  43. Ag 誘起層交換成長法によるSi 極薄膜の形成

    黒澤昌志, 大田晃生, 洗平昌晃, 財満鎭明

    日本表面科学会第35回表面科学学術講演会 

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    Event date: 2015.12

    Language:Japanese   Presentation type:Poster presentation  

    Venue:つくば国際会議場   Country:Japan  

  44. 絶縁膜上のIV 族系二次元結晶に関する第一原理計算

    洗平昌晃, 黒澤昌志, 大田晃生, 白石賢二

    日本表面科学会第35回表面科学学術講演会 

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    Event date: 2015.12

    Language:Japanese   Presentation type:Poster presentation  

    Venue:つくば国際会議場   Country:Japan  

  45. Theoretical Calculations of Electron Transport in Molecular Junction: Inflection Behavior in Fowler-Nordheim Plot and Its Origin International conference

    Masaaki Araidai

    International Workshop on Advanced Nanomaterials for Future Electron Devices 2015 (IWAN2015) 

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    Event date: 2015.11

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

  46. Evaluation of Energy Band Structure of Si1-xSnx by Density Functional Theory Calculation and Photoelectron Spectroscopy International conference

    Y. Nagae, S. Shibayama, M. Kurosawa, M. Araidai, M. Sakashita, O. Nakatsuka, K. Shiraishi, S. Zaima

    2015 International Workshop on DIELECTRIC THIN FILMS FOR FUTURE ELECTRON DEVICES -SCIENCE AND TECHNOLOGY- (IWDTF) 

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    Event date: 2015.11

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

  47. Non-Equilibrium First-Principles Study on Electron Scattering Processes in Magnetic Tunnel Junction International conference

    M. Araidai, T. Yamamoto, K. Shiraishi

    AVS 62nd International Symposium & Exhibition (AVS-62) 

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    Event date: 2015.10

    Language:English   Presentation type:Poster presentation  

    Country:United States  

  48. First principles study on switching mechanism of superlattice(GeTe)2/Sb2Te3 phase change memory International conference

    M. Takato, H. Shirakawa, M. Araidai, K. Shiraishi

    AVS 62nd International Symposium & Exhibition (AVS-62) 

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    Event date: 2015.10

    Language:English   Presentation type:Poster presentation  

    Country:United States  

  49. Ab initio study on the atomic behavior of N, H atoms and O vacancy related defects in SiO2 layer of MONOS memories International conference

    H. Shirakawa, M. Araidai, K. Kamiya, K. Shiraishi

    AVS 62nd International Symposium & Exhibition (AVS-62) 

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    Event date: 2015.10

    Language:English   Presentation type:Poster presentation  

    Country:United States  

  50. First principal calculation of electronic properties on 4H-AlN/4H-SiC(11-20) and 4H-SiC-4H-AlN(0001) interfaces International conference

    K. Endo, H. Shirakawa, M. Araidai, K. Shiraishi

    16th International Conference on Silicon Carbide and Related Materials 

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    Event date: 2015.10

    Language:English   Presentation type:Poster presentation  

    Country:Italy  

  51. Theoretical study on the identity of positive mobile ions in SiC-MOSFET and their diffusion process International conference

    H. Shirakawa, M. Araidai, K. Kamiya, H. Watanabe, K. Shiraishi

    16th International Conference on Silicon Carbide and Related Materials 

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    Event date: 2015.10

    Language:English   Presentation type:Oral presentation (general)  

    Country:Italy  

  52. First-Principles Study on Hydrogen Annealing Effect in Si/SiO2 Interface by Thermal Oxidation International conference

    S. Kawachi, H. Shirakawa, M. Araidai, H. Kageshima, T. Endoh, K. Shiraishi

    2015 International Conference on Solid State Devices and Materials 

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    Event date: 2015.9

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  53. シリコン熱酸化膜の水素アニール効果に関する第一原理計算

    川内伸悟, 白川裕規, 洗平昌晃, 影島博之, 遠藤哲郎, 白石賢二

    シリコン材料・デバイス研究会 (SDM) 

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    Event date: 2015.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:名古屋大学   Country:Japan  

  54. 超格子GeTe/Sb2Te3を用いた相変化メモリのスイッチングメカニズムに関する第一原理計算

    高戸真之, 白川裕規, 洗平昌晃, 白石賢二

    日本物理学会 第70回年次大会(2015年) 

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    Event date: 2015.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:早稲田大学   Country:Japan  

  55. 電流誘起磁化反転における電子散乱過程に関する非平衡第一原理計算

    洗平昌晃,山本貴博,白石賢二

    2015年 第62回応用物理学会春季学術講演会 

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    Event date: 2015.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東海大学   Country:Japan  

  56. MONOS型メモリにおける絶縁膜中の原子欠陥に関する第一原理計算

    白川裕規,洗平昌晃,神谷克政,白石賢二

    2015年 第62回応用物理学会春季学術講演会 

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    Event date: 2015.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東海大学   Country:Japan  

  57. SiC-MOSFETにおけるSiO2絶縁膜中のプロトン拡散についての第一原理計算による検討

    白川裕規, 洗平昌晃, 神谷克政, 渡部平司, 白石賢二

    ゲートスタック研究会 ―材料・プロセス・評価の物理―」(第20回) 

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    Event date: 2015.1

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東レ研修センター   Country:Japan  

  58. 第一原理計算による超格子GeTe/Sb2Te3を用いた相変化メモリ(TRAM)のスイッチングメカニズムの検討

    高戸真之, 白川裕規, 洗平昌晃, 白石賢二

    ゲートスタック研究会 ―材料・プロセス・評価の物理―」(第20回) 

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    Event date: 2015.1

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東レ研修センター   Country:Japan  

  59. 電流誘起磁化反転における電子散乱過程の非平衡第一原理計算

    洗平昌晃,山本貴博,白石賢二

    第19回 半導体スピン工学の基礎と応用 

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    Event date: 2014.12

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京大学   Country:Japan  

  60. Non-Equilibrium First-Principles Study on Electron Scattering Processes in MTJ International conference

    Masaaki Araidai, Takahiro Yamamoto, Kenji Shiraishi

    2014 Workshop on Innovative Nanoscale Devices and Systems (WINDS) 

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    Event date: 2014.11 - 2014.12

    Language:English   Presentation type:Oral presentation (invited, special)  

    Country:United States  

  61. Sb2Te3/GeTe超格子膜からなるTRAMにおけるGeTe配列とスイッチング動作

    大柳孝純, 北村匡史, 加藤重徳, 洗平昌晃, 高浦則克, 白石賢二, 田井光春, 木下勝治, 森川貴博, 秋田憲二

    2014年電気化学秋季大会 

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    Event date: 2014.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  62. 磁気抵抗メモリにおける電子散乱過程の第一原理シミュレーション

    洗平昌晃, 山本貴博, 白石賢二

    電子情報通信学会 ED/CPM/SDM研究会 

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    Event date: 2014.5

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:名古屋大学   Country:Japan  

  63. GeSbTe相変化メモリ素子の電気伝導特性におけるスピン軌道相互作用の効果

    洗平昌晃, 加藤重徳, 山本貴博, 白石賢二

    日本物理学会 第69回年次大会 

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    Event date: 2014.3

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

  64. Understanding the switching mechanism of charge-injection GeTe/Sb2Te3 phase change memory through electrical measurement and analysis of 1R test structure International conference

    N. Takaura, T. Ohyanagi, M. Tai, M. Kitamura, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    27th International Conference on Microelectronic Test Structures  

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    Event date: 2014.3

    Language:English   Presentation type:Oral presentation (general)  

    Country:Italy  

  65. Charge-injection phase change memory with high-quality GeTe/Sb2Te3 superlattice featuring 70-μA RESET, 10-ns SET and 100M endurance cycles operations International conference

    T. Ohyanagi, N. Takaura, M. Tai, M. Kitamura, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    2013 IEEE International Electron Devices Meeting 

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    Event date: 2013.12

    Language:English   Presentation type:Oral presentation (general)  

    Country:United States  

  66. First principle calculation investigation for Si related defect induced by SiC oxidation

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    Event date: 2013.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  67. 磁気抵抗メモリの電流誘起磁化スイッチングに関する第一原理計算

    洗平昌晃, 山本貴博, 白石賢二

    日本物理学会 2013年秋季大会 

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    Event date: 2013.9

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

  68. First-Principles Study on Current-Induced Magnetization Switching in Magnetic Tunnel Junctions International conference

    Masaaki Araidai, Takahiro Yamamoto, Kenji Shiraishi

    IVC-19/ICSS-15 and ICN+T 2013 

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    Event date: 2013.9

    Language:English   Presentation type:Poster presentation  

    Country:Japan  

  69. Charge injection Super-lattice Phase Change Memory for low power and high density storage device applications International conference

    N. Takaura, T. Ohyanagi, M. Kitamura, M. Tai, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    2013 Symposia on VLSI Technology and Circuits 

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    Event date: 2013.6

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

  70. First-Principles Study on Structure and Electron Transport Properties of Phase-Change Memory Device

    Araidai M., Kato S., Yamamoto T., Shiraishi K.

    The Physical Society of Japan 

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    Event date: 2013.3

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

    CiNii Article

  71. Theoretical Calculations of Franck-Condon Blockade Phenomena

    Araidai M., Tsukada M.

    The Physical Society of Japan 

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    Event date: 2012.9

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

    CiNii Article

  72. Theoretical Calculations of Electron Transport in Molecular Junction : Inflection Behavior in Fowler-Nordheim Plot and Its Origin

    Araidai M., Tsukada M.

    The Physical Society of Japan 

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    Event date: 2010.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  73. Atomic Structure and Surface Atom Migration in Gold Junction

    Araidai M., Tsukada M.

    The Physical Society of Japan 

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    Event date: 2009.3

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

    CiNii Article

  74. Ab Initio Study on Electromigration of Gold atom

    Araidai M., Tsukada M.

    The Physical Society of Japan 

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    Event date: 2008.9

    Language:Japanese   Presentation type:Poster presentation  

    Country:Japan  

    CiNii Article

  75. 20aPS-9 Ab Initio Calculation of Force on Tip Atoms under Field Emission II

    Araidai M., Watanabe K.

    The Physical Society of Japan 

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    Event date: 2007

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  76. 25pPSB-7 Ab Initio Calculation of Force on Tip Atoms under Field Emission

    Araidai M., Watanabe K.

    The Physical Society of Japan 

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    Event date: 2006

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  77. 30aPS-15 Ab-Initio Calculations of Field Emission from Carbon Nanostructures

    Araidai Masaaki, Souma Satofumi, Watanabe Kazuyuki

    The Physical Society of Japan 

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    Event date: 2006

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  78. 21aPS-28 First-Principles Analysis of Field Emission by TD-DFT and RTM

    Araidai Masaaki, Souma Satofumi, Watanabe Kazuyuki

    The Physical Society of Japan 

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    Event date: 2005

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  79. Time-dependent density-functional calculation of photoabsorption spectra of organic molecule

    Noguchi Tomoyuki, Nakaoka Noriyuki, Araidai Masaaki, Watanabe Kazuyuki

    The Surface Science Society of Japan 

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    Event date: 2004

    Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  80. 15aPS-5 Time-dependent density-functional calculation of photoabsorption spectra of carbon nanostructure

    Noguchi T., Nakaoka N., Araidai M., Watanabe K.

    The Physical Society of Japan 

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    Event date: 2004

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  81. 27pPSA-4 Field Emission Mechanism of Nanostructures

    Araidai M., Nakamura Y., Watanabe K.

    The Physical Society of Japan 

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    Event date: 2004

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  82. Effect of hydrogen defects on field emission of diamond surfaces

    Araidai Masaaki, Watanabe Kazuyuki

    The Physical Society of Japan 

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    Event date: 2003

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    CiNii Article

  83. Field Emission from Carbon Nanostructures : From Atom to Diamond

    ARAIDAI Masaaki, KANAI Chisato, TADA Kazuhiro, YAMAUCHI Akihiro, WATANABE Kazuyuki

    The Institute of Electronics, Information and Communication Engineers 

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    Event date: 2002.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    Mechanism of field emission from carbon nanostructures is explored by the time-dependent density functional calculations. We determine the the emission current as a function of applied field, energy distribution of electrons emitted, and work functions of carbon atom, silicon atom and clusters, graphitic ribbons, and diamond C(100) surfaces. The present results enable us to stress an important role of the electronic structures, a and π orbitals in field emission from covalent bond materials as well as work functions.

    CiNii Article

  84. Formation of Ultrathin Segregated-Ge Crystal on Al/Ge(111) Surface by Thermal Annealing International conference

    2019.6.21 

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    Language:Japanese   Presentation type:Oral presentation (general)  

  85. 超格子GeTe/Sb₂Te₃メモリの第一原理計算による構造変化シミュレーション International conference

    小川 湧太郎, 野原 弘晶, 白川 裕規, 洗平 昌晃, 白石 賢二

    電子情報通信学会  2019.6.21  電子情報通信学会技術研究報告 = IEICE technical report : 信学技報

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  86. Neural network potential for Si/SiO<sub>2</sub> interface International conference

    Mataka M, Araidai M, Nagura T, Shiraishi K

    The Physical Society of Japan  2018.9.10  Meeting Abstracts of the Physical Society of Japan

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  87. Two-dimensional structure of Ge atoms segregated on Ag(111) International conference

    Shimazu Hiroki, Yuhara Junji, Nakatake Masashi, Ito Kouichi, Ohta Akio, Araidai Masaaki, Kurosawa Masashi

    The Physical Society of Japan  2018.9.9 

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  88. The electric field effect and the dependence of nanoribbon width in monolayer nanoribbons of IV group materials International conference

    Hattori Ayami, Yada Keiji, Araidai Masaaki, Tanaka Yukio

    The Physical Society of Japan  2018.9.9 

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  89. 第一原理計算による超格子GeTe/Sb₂Te₃相変化メモリの理論的検討 International conference

    野原 弘晶, 白川 裕規, 洗平 昌晃, 白石 賢二

    電子情報通信学会  2018.6.25  電子情報通信学会技術研究報告 = IEICE technical report : 信学技報

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  90. First-principles study on hydrogen absorption and desorption of germanene International conference

    Araidai Masaaki, Kurosawa Masashi, Ohta Akio, Shiraishi Kenji

    The Physical Society of Japan  2018.3.24 

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  91. Edge magnetization and an electric field effect in monolayer nanoribbons of IV group materials International conference

    Hattori Ayami, Araidai Masaaki, Tanaka Yukio

    The Physical Society of Japan  2018.3.22 

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  92. Multi-Physics Simulation of GaN MOVPE Growth International conference

    2017.11.9 

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  93. エピタキシャルAg(111)上の極薄Ⅳ族結晶形成 International conference

    伊藤 公一, 大田 晃生, 黒澤 昌志, 洗平 昌晃, 池田 弥央, 牧原 克典, 宮崎 誠一

    電子情報通信学会  2017.6.20  電子情報通信学会技術研究報告 = IEICE technical report : 信学技報

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  94. Electronic states of two-dimensional crystals of group IV element on amorphous insulating films International conference

    Araidai Masaaki, Kurosawa Masashi, Ohta Akio, Shiraishi Kenji

    The Physical Society of Japan  2017.3.17 

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  95. Control of Chemical Reaction between Ag Thin Film and Group-IV Semiconductors International conference

    Ito Koichi, Akio Ohta, Kurosawa Masashi, Araidai Masaaki, Ikeda Mitsuhisa, Makihara Katsunori, Miyazaki Seiichi

    The Surface Science Society of Japan  2016.11.29 

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  96. Chemical synthesis of group-IV nanosheets from layered compounds International conference

    Asaeda Shungo, Kurosawa Masashi, Ohta Akio, Araidai Masaaki, Zaima Shigeaki

    The Surface Science Society of Japan  2016.11.29 

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  97. Electronic states of germanene and stanene on Al<sub>2</sub>O<sub>3</sub> surfaces International conference

    Araidai Masaaki, Kurosawa Masashi, Ohta Akio, Shiraishi Kenji

    The Physical Society of Japan  2016.9.14 

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  98. Electric conduction properties in edge hydrogenated monolayer nanoribbons of group-IV materials International conference

    Hattori Ayami, Araidai Masaaki, Tanaka Yukio

    The Physical Society of Japan  2016.9.14 

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  99. Theoretical Studies on Electronic Structures of Silicene Ribbon and Silicene on Insulator

    K. Shiraishi, A. Hattori, S. Tanaya, M. Araidai, A. Ohta, M. Kurosawa, Y. Hatsugai, M. Sato, Y. Tanaka

    International Symposium on 2D Layered Materials and Art: Two Worlds Meet  2016.3.23 

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  100. Edge states in hydrogenated silicene, germanene, stanene ribbons International conference

    Hattori A, Araidai M, Hatsugai Y, Yada K, Shiraishi K, Sato M, Tanaka Y

    The Physical Society of Japan  2016.3.21  Meeting Abstracts of the Physical Society of Japan

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  101. V-MOSFETにおけるSi/SiO<sub>2</sub>(001)界面における熱酸化過程、水素アニール効果の歪み依存性の第一原理計算による考察 International conference

    川内伸悟, 白川裕規, 洗平昌晃, 影島博之, 遠藤哲郎, 白石賢二

    第63回応用物理学会春季学術講演会  2016.3.19 

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    Venue:東工大 大岡山キャンパス  

  102. GaN結晶成長メカニズムの熱力学解析 International conference

    関口一樹, 白川裕規, 山本芳裕, 洗平昌晃, 白石賢二

    第63回応用物理学会春季学術講演会  2016.3.19 

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    Venue:東工大 大岡山キャンパス  

  103. SiC/GaNの界面構造とバンドオフセットとの関係の理論的検討 International conference

    小嶋英嗣, 遠藤賢太郎, 白川裕規, 洗平昌晃, 海老原康裕, 金村高司, 恩田正一, 白石賢二

    第63回応用物理学会春季学術講演会  2016.3.19 

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    Venue:東工大 大岡山キャンパス  

  104. First-principles study on two-dimensional crystals of group IV material on insulating film International conference

    Araidai M, Kurosawa M, Ohta A, Shiraishi K

    The Physical Society of Japan  2016.3.19 

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  105. 絶縁膜上にあるIV族系二次元結晶の電子状態解析 International conference

    洗平昌晃, 黒澤昌志, 大田晃生, 白石賢二

    日本物理学会 第71回年次大会(2016年)  2016.3.19 

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    Venue:東北学院大学 泉キャンパス  

  106. 水素終端シリセン、ゲルマネン、スタネンリボンにおけるエッジ状態 International conference

    服部綾実, 洗平昌晃, 初貝安弘, 矢田圭司, 白石賢二, 佐藤昌利, 田仲由喜夫

    日本物理学会 第71回年次大会(2016年)  2016.3.19 

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    Venue:東北学院大学 泉キャンパス  

  107. Characterization of Chemical Bonding Features of Ultrathin Ge Layer Grown by Ag-Induced Layer-Exchange Method

    A. Ohta, M. Kurosawa, M. Araidai, S. Miyazaki

    8th International Symposium on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials / 9th International Conference on Plasma-Nano Technology & Science (ISPlasma2016/IC-PLANTS2016)  2016.3.6 

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  108. MONOSメモリにおけるSiO<sub>2</sub>膜中の窒素原子に起因する原子欠陥の理論的考察 International conference

    白川裕規, 洗平昌晃, 神谷克政, 白石賢二

    電子デバイス界面テクノロジー研究会(第21回)  2016.1.22 

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    Venue:東レ研修センター(静岡県三島市)  

  109. Si/SiO<sub>2</sub>(100)界面における熱酸化過程、水素アニール効果の 歪み依存性に関する理論的研究 International conference

    川内伸悟, 白川裕規, 洗平昌晃, 影島愽之, 遠藤哲郎, 白石賢二

    電子デバイス界面テクノロジー研究会(第21回)  2016.1.22 

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    Venue:東レ研修センター(静岡県三島市)  

  110. Si<sub>1-x</sub>Sn<sub>x</sub>半導体のエネルギーバンド構造に関する理論的および実験的分析 International conference

    長江祐樹, 柴山茂久, 黒澤昌志, 洗平昌晃, 中塚理, 白石賢二, 財満鎭明

    電子デバイス界面テクノロジー研究会(第21回)  2016.1.22 

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    Venue:東レ研修センター(静岡県三島市)  

  111. First-principles study on two-dimensional crystals of group IV element on insulating film

    M. Araidai, M. Kurosawa, A. Ohta, K. Shiraishi

    23rd International Colloquium on Scanning Probe Microscopy (ICSPM23)  2015.12.10 

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  112. Si and Ge Ultrathin Films by Ag-Induced Layer-Exchange Growth

    M. Kurosawa, A. Ohta, M. Araidai, S. Zaima

    23rd International Colloquium on Scanning Probe Microscopy (ICSPM23)  2015.12.10 

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  113. First principles examination of the switching mechanism of the phase change memory (TRAM) using superlattice GeTe/Sb<sub>2</sub>Te<sub>3</sub>

    M. Takato, H. Shirakawa, M. Araidai, K. Shiraishi

    46th Semiconductor Interface Specialists Conference (SISC2015)  2015.12.2 

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  114. Ag 誘起層交換成長法によるSi 極薄膜の形成 International conference

    黒澤昌志, 大田晃生, 洗平昌晃, 財満鎭明

    日本表面科学会第35回表面科学学術講演会  2015.12.1 

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    Venue:つくば国際会議場  

  115. 絶縁膜上のIV 族系二次元結晶に関する第一原理計算 International conference

    洗平昌晃, 黒澤昌志, 大田晃生, 白石賢二

    日本表面科学会第35回表面科学学術講演会  2015.12.1 

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    Venue:つくば国際会議場  

  116. Theoretical Calculations of Electron Transport in Molecular Junction: Inflection Behavior in Fowler-Nordheim Plot and Its Origin

    Masaaki Araidai

    International Workshop on Advanced Nanomaterials for Future Electron Devices 2015 (IWAN2015)  2015.11.7 

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  117. Evaluation of Energy Band Structure of Si<sub>1-x</sub>Sn<sub>x</sub> by Density Functional Theory Calculation and Photoelectron Spectroscopy

    Y. Nagae, S. Shibayama, M. Kurosawa, M. Araidai, M. Sakashita, O. Nakatsuka, K. Shiraishi, S. Zaima

    2015 International Workshop on DIELECTRIC THIN FILMS FOR FUTURE ELECTRON DEVICES -SCIENCE AND TECHNOLOGY- (IWDTF)  2015.11.2 

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  118. Ab initio study on the atomic behavior of N, H atoms and O vacancy related defects in SiO<sub>2</sub> layer of MONOS memories

    H. Shirakawa, M. Araidai, K. Kamiya, K. Shiraishi

    AVS 62nd International Symposium & Exhibition (AVS-62)  2015.10.18 

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  119. Non-Equilibrium First-Principles Study on Electron Scattering Processes in Magnetic Tunnel Junction

    M. Araidai, T. Yamamoto, K. Shiraishi

    AVS 62nd International Symposium & Exhibition (AVS-62)  2015.10.18 

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  120. First principles study on switching mechanism of superlattice(GeTe)<sub>2</sub>/Sb<sub>2</sub>Te<sub>3</sub> phase change memory

    M. Takato, H. Shirakawa, M. Araidai, K. Shiraishi

    AVS 62nd International Symposium & Exhibition (AVS-62)  2015.10.18 

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  121. First principal calculation of electronic properties on 4H-AlN/4H-SiC(11-20) and 4H-SiC-4H-AlN(0001) interfaces

    K. Endo, H. Shirakawa, M. Araidai, K. Shiraishi

    16th International Conference on Silicon Carbide and Related Materials  2015.10.4 

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  122. Theoretical study on the identity of positive mobile ions in SiC-MOSFET and their diffusion process

    H. Shirakawa, M. Araidai, K. Kamiya, H. Watanabe, K. Shiraishi

    16th International Conference on Silicon Carbide and Related Materials  2015.10.4 

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  123. First-Principles Study on Hydrogen Annealing Effect in Si/SiO<sub>2</sub> Interface by Thermal Oxidation

    S. Kawachi, H. Shirakawa, M. Araidai, H. Kageshima, T. Endoh, K. Shiraishi

    2015 International Conference on Solid State Devices and Materials  2015.9.27 

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  124. シリコン熱酸化膜の水素アニール効果に関する第一原理計算 International conference

    川内伸悟, 白川裕規, 洗平昌晃, 影島博之, 遠藤哲郎, 白石賢二

    シリコン材料・デバイス研究会 (SDM)  2015.6.19 

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    Venue:名古屋大学  

  125. 超格子GeTe/Sb2Te3を用いた相変化メモリのスイッチングメカニズムに関する第一原理計算 International conference

    高戸真之, 白川裕規, 洗平昌晃, 白石賢二

    日本物理学会 第70回年次大会(2015年)  2015.3.21 

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    Venue:早稲田大学  

  126. MONOS型メモリにおける絶縁膜中の原子欠陥に関する第一原理計算 International conference

    白川裕規, 洗平昌晃, 神谷克政, 白石賢二

    2015年 第62回応用物理学会春季学術講演会  2015.3.11 

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    Venue:東海大学  

  127. 電流誘起磁化反転における電子散乱過程に関する非平衡第一原理計算 International conference

    洗平昌晃, 山本貴博, 白石賢二

    2015年 第62回応用物理学会春季学術講演会  2015.3.11 

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    Venue:東海大学  

  128. SiC-MOSFETにおけるSiO2絶縁膜中のプロトン拡散についての第一原理計算による検討 International conference

    白川裕規, 洗平昌晃, 神谷克政, 渡部平司, 白石賢二

    ゲートスタック研究会 ―材料・プロセス・評価の物理―」(第20回)  2015.1.24 

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    Venue:東レ研修センター  

  129. 第一原理計算による超格子GeTe/Sb2Te3を用いた相変化メモリ(TRAM)のスイッチングメカニズムの検討 International conference

    高戸真之, 白川裕規, 洗平昌晃, 白石賢二

    ゲートスタック研究会 ―材料・プロセス・評価の物理―」(第20回)  2015.1.24 

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    Venue:東レ研修センター  

  130. 電流誘起磁化反転における電子散乱過程の非平衡第一原理計算 International conference

    洗平昌晃, 山本貴博, 白石賢二

    第19回 半導体スピン工学の基礎と応用  2014.12.15 

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    Venue:東京大学  

  131. Non-Equilibrium First-Principles Study on Electron Scattering Processes in MTJ

    Masaaki Araidai, Takahiro Yamamoto, Kenji Shiraishi

    2014 Workshop on Innovative Nanoscale Devices and Systems (WINDS)  2014.11.30 

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  132. Sb2Te3/GeTe超格子膜からなるTRAMにおけるGeTe配列とスイッチング動作 International conference

    大柳孝純, 北村匡史, 加藤重徳, 洗平昌晃, 高浦則克, 白石賢二, 田井光春, 木下勝治, 森川貴博, 秋田憲二

    2014年電気化学秋季大会  2014.9.27 

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  133. 磁気抵抗メモリにおける電子散乱過程の第一原理シミュレーション International conference

    洗平昌晃, 山本貴博, 白石賢二

    電子情報通信学会 ED/CPM/SDM研究会  2014.5.28 

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    Venue:名古屋大学  

  134. GeSbTe相変化メモリ素子の電気伝導特性におけるスピン軌道相互作用の効果 International conference

    洗平昌晃, 加藤重徳, 山本貴博, 白石賢二

    日本物理学会 第69回年次大会  2014.3.27 

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  135. Understanding the switching mechanism of charge-injection GeTe/Sb2Te3 phase change memory through electrical measurement and analysis of 1R test structure

    N. Takaura, T. Ohyanagi, M. Tai, M. Kitamura, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    27th International Conference on Microelectronic Test Structures  2014.3.25 

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  136. Charge-injection phase change memory with high-quality GeTe/Sb2Te3 superlattice featuring 70-μA RESET, 10-ns SET and 100M endurance cycles operations

    T. Ohyanagi, N. Takaura, M. Tai, M. Kitamura, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    2013 IEEE International Electron Devices Meeting  2013.12.9 

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  137. First principle calculation investigation for Si related defect induced by SiC oxidation International conference

    2013.12.9 

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  138. 磁気抵抗メモリの電流誘起磁化スイッチングに関する第一原理計算 International conference

    洗平昌晃, 山本貴博, 白石賢二

    日本物理学会 2013年秋季大会  2013.9.25 

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  139. First-Principles Study on Current-Induced Magnetization Switching in Magnetic Tunnel Junctions

    Masaaki Araidai, Takahiro Yamamoto, Kenji Shiraishi

    IVC-19/ICSS-15 and ICN+T 2013  2013.9.9 

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  140. Charge injection Super-lattice Phase Change Memory for low power and high density storage device applications

    N. Takaura, T. Ohyanagi, M. Kitamura, M. Tai, M. Kinoshita, K. Akita, T. Morikawa, S. Kato, M. Araidai, K. Kamiya, T. Yamamoto, K. Shiraishi

    2013 Symposia on VLSI Technology and Circuits  2013.6.11 

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  141. First-Principles Study on Structure and Electron Transport Properties of Phase-Change Memory Device International conference

    Araidai M, Kato S, Yamamoto T, Shiraishi K

    The Physical Society of Japan  2013.3.26 

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  142. Theoretical Calculations of Franck-Condon Blockade Phenomena International conference

    Araidai M, Tsukada M

    The Physical Society of Japan  2012.9.26 

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  143. Theoretical Calculations of Electron Transport in Molecular Junction : Inflection Behavior in Fowler-Nordheim Plot and Its Origin International conference

    Araidai M, Tsukada M

    The Physical Society of Japan  2010.3.21 

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  144. Atomic Structure and Surface Atom Migration in Gold Junction International conference

    Araidai M, Tsukada M

    The Physical Society of Japan  2009.3.29 

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  145. Ab Initio Study on Electromigration of Gold atom International conference

    Araidai M, Tsukada M

    The Physical Society of Japan  2008.9.22 

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  146. 20aPS-9 Ab Initio Calculation of Force on Tip Atoms under Field Emission II International conference

    Araidai M, Watanabe K

    The Physical Society of Japan  2007  Meeting Abstracts of the Physical Society of Japan

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  147. 25pPSB-7 Ab Initio Calculation of Force on Tip Atoms under Field Emission International conference

    Araidai M, Watanabe K

    The Physical Society of Japan  2006  Meeting Abstracts of the Physical Society of Japan

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  148. 30aPS-15 Ab-Initio Calculations of Field Emission from Carbon Nanostructures International conference

    Araidai Masaaki, Souma Satofumi, Watanabe Kazuyuki

    The Physical Society of Japan  2006  Meeting Abstracts of the Physical Society of Japan

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  149. 21aPS-28 First-Principles Analysis of Field Emission by TD-DFT and RTM International conference

    Araidai Masaaki, Souma Satofumi, Watanabe Kazuyuki

    The Physical Society of Japan  2005  Meeting Abstracts of the Physical Society of Japan

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  150. 15aPS-5 Time-dependent density-functional calculation of photoabsorption spectra of carbon nanostructure International conference

    Noguchi T, Nakaoka N, Araidai M, Watanabe K

    The Physical Society of Japan  2004  Meeting Abstracts of the Physical Society of Japan

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  151. 27pPSA-4 Field Emission Mechanism of Nanostructures International conference

    Araidai M, Nakamura Y, Watanabe K

    The Physical Society of Japan  2004  Meeting Abstracts of the Physical Society of Japan

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  152. Time-dependent density-functional calculation of photoabsorption spectra of organic molecule International conference

    Noguchi Tomoyuki, Nakaoka Noriyuki, Araidai Masaaki, Watanabe Kazuyuki

    The Surface Science Society of Japan  2004  Abstract of annual meeting of the Surface Science of Japan

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  153. Effect of hydrogen defects on field emission of diamond surfaces International conference

    Araidai Masaaki, Watanabe Kazuyuki

    The Physical Society of Japan  2003  Meeting Abstracts of the Physical Society of Japan

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  154. Field Emission from Carbon Nanostructures : From Atom to Diamond International conference

    ARAIDAI Masaaki, KANAI Chisato, TADA Kazuhiro, YAMAUCHI Akihiro, WATANABE Kazuyuki

    The Institute of Electronics, Information and Communication Engineers  2002.12.6  IEICE technical report. Electron devices

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    Mechanism of field emission from carbon nanostructures is explored by the time-dependent density functional calculations. We determine the the emission current as a function of applied field, energy distribution of electrons emitted, and work functions of carbon atom, silicon atom and clusters, graphitic ribbons, and diamond C(100) surfaces. The present results enable us to stress an important role of the electronic structures, a and π orbitals in field emission from covalent bond materials as well as work functions.

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Works 3

  1. プレスリリース「振動発電素子の帯電機構の微視的解明」

    2020.11

  2. プレスリリース「新型相変化デバイスのTRAMの熱安定化指針を世界ではじめて確立 -データセンター省電力化・低炭素化に期待-」

    2014.6

  3. プレスリリース「0.37Vで動作する超低電圧デバイスを開発 -IT機器の消費電力1/10などの実現に道-」

    2013.6

Research Project for Joint Research, Competitive Funding, etc. 2

  1. ナノスケール次世代電子デバイスの第一原理電子状態計算に基づく理論研究

    2015.10

    第31回海外派遣助成金 

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    Grant type:Competitive

  2. カルコゲン化合物・超格子のトポロジカル相転移を利用した二次元マルチフェロイック機能デバイスの創製

    2014.10 - 2020.3

    戦略的創造研究推進事業 

    富永淳二

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    Authorship:Coinvestigator(s)  Grant type:Competitive

KAKENHI (Grants-in-Aid for Scientific Research) 19

  1. Formation of Ge two-dimensional crystals embedded into Si oxide and its device application

    Grant number:20K21142  2020.7 - 2022.3

    Grant-in-Aid for Challenging Research (Exploratory)

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    Authorship:Coinvestigator(s)  Grant type:Competitive

  2. 第一原理計算からの気液固複合相ヘテロ界面の実在系非平衡シミュレーション

    Grant number:19K22044  2019.6 - 2021.3

    日本学術振興会  科学研究費助成事業 挑戦的研究(萌芽)  挑戦的研究(萌芽)

    多田 朋史

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    Authorship:Coinvestigator(s)  Grant type:Competitive

    Grant amount:\2300000 ( Direct Cost: \2300000 )

    デバイス性能を議論する際、バルク材料と他相とのヘテロ接合界面の微視的情報の把握が重要であるが、これは大変困難な課題である。それは、原子、分子、イオンが各相に流れ込むことによる不定比組成状態の出現と、反応・拡散速度の違いによる非平衡性のため、ヘテロ界面の実態を微視的に決定することが極めて困難なためである。よって、本研究は第一原理計算を利用した網羅的素過程探索と、気液固複合相の非平衡状態を記述できる長時間ダイナミクス手法とを融合することで気液固複合相ヘテロ界面の実在系非平衡シミュレーションを達成し、新しい計算技術の潮流を生み出すことを目的としたものである。
    第一原理電子状態計算の進歩によりバルク材料物性の高精度予測が可能となったが、デバイスとしての性能を議論する際に重要であるバルク材料と他相(気相、液相、固相)との接合界面(ヘテロ界面)に関しては計算技術の飛躍的進展が必要とされている 。これは、原子、分子、イオンが各相に流れ込むことによる不定比組成状態がヘテロ界面に出現することに加え、各素過程に依存した反応・拡散速度の違いによる非平衡性のため 、ヘテロ界面の実態を微視的に決定することが極めて困難なためである。既存の第一原理分子動力学計算では到達不可能な時空間スケールの現象である。よって、ヘテロ界面の正確な微視的モデリングからデバイス設計への道筋を確立するためには、第一原理電子状態計算を利用した網羅的素過程探索と、気液固複合相の非平衡状態を記述できる長時間ダイナミクス手法との融合が必須である。本研究は、代表者開発の大規模開放系動的モンテカルロ法と分担者開発のマルチカノニカル法を発展的に融合することで気液固複合相ヘテロ界面の実在系非平衡シミュレーションを実現し、新しい計算技術の潮流を生み出すことを目的とした研究である。
    上記の目標を達成すべく、H31年度(令和元年度)は代表者による動的モンテカルロ用の液体状態の記述法確立と大規模開放系動的モンテカルロ法の更なる高速化、分担者による第一原理計算を用いた網羅的素過程探索と第一原理計算の高速化、を実行した。
    H31年度(令和元年度)は代表者による動的モンテカルロ用の液体状態の記述法確立と大規模開放系動的モンテカルロ法の更なる高速化、分担者による第一原理計算を用いた網羅的素過程探索と第一原理計算の高速化、を実行した。動的モンテカルロ用の液体状態の記述法としては、2つの手法について検討を行った。1:固体用動的モンテカルロ法のグリッド手法を採用、2:ニューラルネットワークポテンシャル分子動力学と動的モンテカルロ法との融合。いずれの手法も十分に実行性の高い手法であることを確認した。大規模開放系動的モンテカルロ法の更なる高速化としては、現状のプログラムにおけるホットスポットであるポアソンソルバー部分の高速化に成功した。第一原理計算を用いた網羅的素過程探索では、欠陥を含む酸化物を対象として、その系における網羅的素過程探索を実行し同手法の有効性を確認した。第一原理計算の高速化ではニューラルネットワークポテンシャルを導入することで、第一原理計算の精度をおとすことなく1000倍程度の高速化を達成した。以上の通り、H31年度(令和元年度)の計画を順調に達成し、最終目標に向けて研究は進展している。
    令和2年度(最終年度)は、高速化された液体用動的モンテカルロを用いて、複雑系をターゲットとした網羅的素過程探索実行後、巨視的な時間スケールにわたる動力学計算を実行する計画である。また、同目標を達成する上で、電子ダイナミクスを取り入れることの重要性も明らかとなり、当初の計画では含めていなかった動的モンテカルロ法による電子ダイナミクス記述法の構築も含めることとした。研究推進としては、本来であれば代表者と分担者それぞれの活動拠点で定期的な打ち合わせを行うことが望ましいが、昨年12月ごろから世界的に蔓延しだしたコロナウイルスの影響により、個々の拠点からは移動せず、電子メールやWeb会議等を用いて継続的に打ち合わせを行う予定である。代表者と分担者が開発している個々の技術の有機的な融合が望ましいが、目標達成においてはそれぞれの技術とそこで得られた情報をカスケード的に用いることで達成できるため、研究推進としては上記のもので十分であると考えている。

  3. Si-Ge系スーパーアトムの内部ポテンシャル変調による量子機能材料創成

    Grant number:19H00762  2019.4 - 2023.3

    日本学術振興会  科学研究費助成事業 基盤研究(A)  基盤研究(A)

    牧原 克典

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    本研究では、Si-Ge系スーパーアトム(コア/シェル量子ドット)において、電子および正孔の波動関数制御技術を確立し、均質ナノドットにない固有の物性・機能を実現する。具体的には、GeコアSi量子ドットにおいて、計算科学、半導体プロセスおよび物性評価の各研究者が、それぞれの分野の専門性を生かした相互・有機的連携による新しい視点からナノ構造界面を有する量子井戸に閉じ込めた電子・正孔の波動関数を深考し、スーパーアトム内での電子・正孔の結合・分離状態制御を実現する。これにより、真の量子力学に基づいた波動関数カップリングを実現し、高効率キャリア再結合を実現するSi系エレクトロルミネッセンス材料を創成する。
    初年度は、Si/Geスーパーアトム構造において、Geの選択成長温度が室温発光へ及ぼす影響を調べるとともに、Geコア内へのBデルタドーピングがPL特性に及ぼす影響を評価した。
    具体的には、n-Si(100)基板上に膜厚~3nmの酸化膜を形成し、pure-SiH4を用いたLPCVDによりSi量子ドットを高密度・一括形成した。続いて、H2希釈5%GeH4のLPCVDによりSi量子ドット上にGeを選択的に成長した。このとき、基板温度は450℃および500℃とし、ドット平均高さが~6-7nmとなるように成長時間を制御した。その後、H2希釈5%SiH4のLPCVDを用いた選択成長により、580℃でGeをSiで被覆することでGeコアSi量子ドットを形成した。形成した試料の室温PLを測定した結果、Geコアの成長温度に依らず、波長1700nm付近にGeコア中の量子化準位を介したブロード発光が認められるが、450℃でGeを選択成長した場合の発光強度は、500℃で成長したGeコアSi量子ドットに比べ、約1桁高いことが分かった。各々の試料のラマン散乱スペクトルを測定した結果、500℃でGeコアを形成した場合には、僅かながらSi-Geに起因するピークが認められるものの、450℃のGeコアでは殆ど認められなかった。これらの結果は、Geを低温で選択成長することで、下地Si量子ドットとGeコア界面のミキシングが抑制され、極めて組成急峻且つ低欠陥密度な界面が得られたことで、Geコア中での発光再結合レートが増大したとして解釈できる。また、Geコア形成時に1%He希釈B2H6ガスをパルス導入することでB添加を行った場合、PL強度が真正ドットに比べ1.4倍に増大することが分かった。これは、Geコアの深いポテンシャル井戸に閉じ込められた正孔数の増加により、発光再結合レートが増大した結果として解釈できる。
    本研究では、Si-Ge系スーパーアトム(コア/シェル量子ドット)において、電子および正孔の波動関数制御技術を確立し、均質ナノドットにない固有の物性・機能の実現による高効率キャリア再結合を実現するSi系エレクトロルミネッセンス材料の創成を目的としている。初年度では、高効率キャリア再結合を実現可能とする不純物添加や各プロセスを精査することで、発光強度の増大を実現しており、当初の予定通り進展していると言える。
    今後は、Geコア/Siシェル量子ドットの高密度形成と高効率発光素子の開発とともに、キャリアダイナミックスと光学特性に対する電界効果評価を実施する。具体的には、Geコアサイズ、Siシェル厚みを変化させた試料を作成し、コア/シェル界面のミキシング、歪、電子状態を評価し、発光特性に及ぼす影響を明らかにする。また、Geコア/Siシェル量子ドットを活性層とするダイオード構造を設計・作製し、電界印加が発光特性に与える効果を明らかにする。ダイオード構造においては、GeコアSi量子ドットの上部に厚い酸化膜層を形成して、その上部に形成した電極層とドット間でのキャリアの注入・放出を抑制した試料において、正負バイアスの連続パルス印加によって基板側からドットへ電子・正孔を交互に注入したときの発光特性を評価する。さらには、これらの実験と並行して「第一原理計算によるナノ構造界面の物性予測」の観点からGeコアSi量子ドットを探求し、得られる知見を体系的に整理・統合することで新たな概念に基づくSi系エレクトロルミネッセンス材料を創成する。

  4. Semiconductor electron beam source that brings fine-area dynamics observation technology to damage sensitive samples

    Grant number:19H00666  2019.4 - 2022.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Authorship:Coinvestigator(s) 

  5. 一般化アンサンブル法を用いたGaN結晶成長の解析

    Grant number:19H04541  2019.4 - 2021.3

    日本学術振興会  科学研究費助成事業 新学術領域研究(研究領域提案型)  新学術領域研究(研究領域提案型)

    洗平 昌晃

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\3770000 ( Direct Cost: \2900000 、 Indirect Cost:\870000 )

    本研究は申請者が開発している自由エネルギー解析手法(一般化アンサンブル法)を用いて,GaNの結晶成長の全貌を明らかにしようとする萌芽的研究である.GaNは次世代の電力用半導体素子(パワーデバイス)として盛んに研究されており,これが実現されると著しい省エネルギー社会が到来すると期待されている.本研究で用いる手法は,従来の電子状態計算手法が苦手とする熱力学的・統計力学的観点を表に出したものである.したがって,本研究終了の暁には,実験と理論の橋渡し役として確立してきた計算物質科学の分野により強固な一面をもたらすことが期待される.
    窒化ガリウム(GaN)の結晶成長における気相反応に対して,申請者が開発した自由エネルギー計算を適用した.第一原理電子状態計算手法をエネルギー計算器として計算を実行し,Ga(CH3)3がH2やNH3分子と反応する際の自由エネルギーランドスケープを得ることができた.しかしながら,得られた自由エネルギーランドスケープから速度論パラメータを得るためには,その精度がまだ不十分であった.その上,計算に要した時間は想像以上であり,この計算を複数回実行するのが厳しいことが分かった.この問題を解決するために,ニューラルネットワークによる古典ポテンシャルを作成し,それをエネルギー計算器として採用し自由エネルギー計算を実行したところ,その計算速度は今後研究を推進していくうえで非常に現実的なものであった.しかしながら,学習していない領域(外挿領域)の構造がたびたび出現したため、分子構造が不自然に分解してしまった.一般的に,非線形回帰に基づく機械学習のアルゴリズムは,外挿領域に対して予測精度が著しく低下することが知られている.従来のニューラルネットワークポテンシャルの作成方法では学習データの重複を排除することができず,これが学習データの収集に大きな制限をかけることになり、ひいてはニューラルネットワークポテンシャルの精度の悪化(外挿問題)と学習の非効率化をもたらしている.今後は原子ごとにニューラルネットワークポテンシャルを学習する方針に転換する.これにより,ニューラルネットワークの入力値の分布が均等となるように学習データを収集することができ効率の良い学習が可能となる.さらに,特徴的な環境にいる原子を漏らさず抽出することができるためニューラルネットワークの外挿問題に対しても改善が期待される.今後は,この方針でロバストなニューラルネットワークポテンシャルを作成し研究を推進する.
    窒化ガリウム(GaN)の結晶成長における気相反応では,様々なプロセスを経てGa(CH3)3からGaHに分解すると考えられている.これらのプロセスに対して申請者が開発した自由エネルギー計算を適用した.第一原理電子状態計算手法をエネルギー計算器として計算を実行し,Ga(CH3)3がH2やNH3分子と反応する際の自由エネルギーランドスケープを得ることができた.しかしながら,得られた自由エネルギーランドスケープから速度論パラメータ(活性化障壁高さや試行頻度)を得るためには,その精度がまだ不十分であった.その上,計算に要した時間は想像以上であり,この計算を複数回実行するのが厳しいことが分かった.この問題を解決するために,機械学習手法の一つであるニューラルネットワークによる古典ポテンシャルを作成し,それをエネルギー計算器として採用し自由エネルギー計算を実行した.第一原理電子状態計算手法をエネルギー計算器とした場合に比べて2000倍も速い計算速度が得られた.今後研究を推進していくうえで非常に現実的な計算速度である.しかしながら,学習していない領域(外挿領域)の構造がたびたび出現し、不自然な力が原子に加わったため分子構造が不自然に分解してしまった.今後はこの問題を解決し,ニューラルネットワークポテンシャルをエネルギー計算器とした自由エネルギー計算を実施していく.二年目には気相反応で生成されたGaH分子がGaN基板に吸着されるプロセス,ならびに吸着した分子にNH3分子が反応するプロセスに対して自由エネルギー計算を実施する予定であったが,気相反応の解析に今しばらく時間が必要である.
    計算手法である第一原理マルチカノニカルモンテカルロ法は,並列化効率は非常に高いものの,想像以上に計算時間を要することが判明した.この計算を実行しつつ,非常に高速なニューラルネットワークポテンシャルによる計算も実行していく.しかしながら,特に今回の様に非常に自由度の高い気体分子(気相)の反応に対して,ニューラルネットワークポテンシャルによる計算を安定に実行するためには解決すべき問題がある.実際にニューラルネットワークポテンシャルで計算を実行すると,学習していない領域(外挿領域)の構造がたびたび出現し、不自然な力が原子に加わったため分子構造が不自然に分解してしまう.一般的に,非線形回帰に基づく機械学習のアルゴリズムは,外挿領域に対して予測精度が著しく低下することが知られている.従来のニューラルネットワークポテンシャルの作成方法では学習データの重複を排除することができず,これが学習データの収集に大きな制限をかけることになり、ひいてはニューラルネットワークポテンシャルの精度の悪化(外挿問題)と学習の非効率化をもたらしている.今後は原子ごとにニューラルネットワークポテンシャルを学習する方針に転換する.これにより,ニューラルネットワークの入力値の分布が均等となるように学習データを収集することができ効率の良い学習が可能となる.さらに,特徴的な環境にいる原子を漏らさず抽出することができるためニューラルネットワークの外挿問題に対しても改善が期待される.今後は,この方針でロバストなニューラルネットワークポテンシャルを作成し研究を推進する.

  6. Self-organized Formation of Ge-based Two-dimensional Crystals and Control of Crystalline Structure and Electronic State

    Grant number:18K19020  2018.6 - 2020.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Challenging Research (Exploratory)  Grant-in-Aid for Challenging Research (Exploratory)

    Ohta Akio

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    Authorship:Coinvestigator(s)  Grant type:Competitive

    Grant amount:\1400000 ( Direct Cost: \1400000 )

    We have studied the chemical and crystallographic structures of vacuum evaporated Al/Ge(111) before and after the thermal annealing to form the germenium (Ge) two dimensional (2D) crystals on the surface by the control of Ge segregation from Al. Hetero-epitaxial Al layer was found to be grown on Ge(111) substrate by controls of the Al thickness and deposition rate during the vacuum evaporation, which Al surface becomes the template of crystallographic structure of segregated Ge layer. The surface flattening and Ge segregation on Al/Ge(111) structure by the annealing have been systematically investigated, and the sub-nm-thick ultrathin segragated-Ge crystalline can be formed on the hetero-epitaxial Al surface.

  7. Clarification of interface formation and electronic properties of power semiconductors through quantum theoretical computics

    Grant number:18H03873  2018.4 - 2022.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Authorship:Coinvestigator(s)  Grant type:Competitive

  8. 量子論コンピューティクスによるパワー半導体界面形成機構と電子物性の解明

    2018.4 - 2021.3

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    押山淳, 洗平昌晃, 松下雄一郎

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    Grant type:Competitive

  9. ゲルマニウム系二次元ハニカム結晶の自己組織化形成と結晶構造・電子状態制御

    2018.4 - 2020.3

    科学研究費助成事業  挑戦的研究(萌芽)

    大田晃生, 黒澤昌志, 洗平昌晃

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    Grant type:Competitive

  10. Development of free-energy calculation method based on the first-principles electronic-structure calculations and its application

    Grant number:16K17551  2016.4 - 2019.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)  Grant-in-Aid for Young Scientists (B)

    Araidai Masaaki

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    The operating mechanism of energy-saving devices and next-generation battery is based on complex phenomena mediated by a huge variety of electronic states between a lot of atoms or molecules. In order to analyze such phenomena, I developed the free-energy calculation method, which describe statistical-mechanical properties of a system, coupled with the first-principles electronic-structure calculations. However, the developed calculation method is unexpectedly demanding to obtain realistic sampling. Therefore, I have also developed highly accurate interatomic potential based on artificial neural network. I investigated oxygen vacancy diffusion in ferroelectric BaTiO3 and gas generation in electrolyte solution by decomposition of the solution molecules by the calculation method developed in this research subject to obtain the valuable results for understanding these phenomena.

  11. ナノスケール次世代電子デバイスの第一原理電子状態計算に基づく理論研究

    2015.10

    日東学術振興財団  第31回海外派遣助成金 

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    Grant type:Competitive

  12. Synthesis of New Group IV Two Dimensional Materials

    Grant number:15H03564  2015.4 - 2018.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    Shiraishi Kenji

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid) 

    We performed first principles calculations of of silicene and germanene and clarified the atomic and electronic structures. First, we performed electronic structure of silicene and germanene on Al2O3 insulators. As a result, band structures of silicene and germanene keep dirac cone characteristic at K point even after it is adsorbed on Al2O3. However, band structures are slightly modified dependeng of the adsorbed structures of silicene and gemanene.

  13. Growth and Characterization of Silicon-based Two-Dimensional Materials

    Grant number:15K13943  2015.4 - 2017.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research  Grant-in-Aid for Challenging Exploratory Research

    Ohta Akio

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    Authorship:Coinvestigator(s)  Grant type:Competitive

    Grant amount:\1000000 ( Direct Cost: \1000000 )

    We have studied a new growth technique of Si- or Ge-based two-dimentional crystal. An epitaxial Ag(111) layer was grown on Si(111) (or Ge(111)) substrate, and a segregation of Si (or Ge) on the epitaxial Ag(111) by the annealing in nitrogen ambience was found to be detected. In addition, the amount of the segregated Si (or Ge) could be controlled by the annealing condition such as time and temperature. As a highlight, a periodic structure of bi-layer Ge atom corresponding to a two-dimensional crystal on the atomically flat Ag surface were clearly observed from the high resolution cross section TEM image of the Ag/Ge structure after the annealing at 450 degree.

  14. カルコゲン化合物・超格子のトポロジカル相転移を利用した二次元マルチフェロイック機能デバイスの創製

    2014.10 - 2020.3

    国立研究開発法人 科学技術振興機構  戦略的創造研究推進事業 

    富永淳二

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    Grant type:Competitive

  15. ナノ空間における溶液物性と電気化学過程の理論的解明

    2009.4 - 2013.3

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    塚田捷, 赤木和人, 田村宏之, 濱田幾太郎, 真砂啓

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    Grant type:Competitive

  16. Theoretical study on property of aqueous solution and electrochemical process at nano-space

    Grant number:21244045  2009 - 2012

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)  Grant-in-Aid for Scientific Research (A)

    TSUKADA Masaru

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid) 

    Structure and dynamics of aqueous electrolyte solution at the solid-liquid interface was investigated based on various molecular simulation methods. Microscopic understanding on typical space and time scale of interfacial systems, behavior of ionic species in a hydrogen-bond network and the origin of electric double layer structure were given. Hydrogen evolution processes at an “acid solution / Pt electrode" interface were quantitatively evaluated taking account of the effect of electrode potential. Theoretical frameworks to treat the electron transfer process across the interface induced by photo excitation or applied electric field were developed.

  17. 時間依存密度汎関数法による炭素系ナノ構造の非平衡電子状態の研究

    2004.4 - 2007.3

    科学研究費補助金 

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    Authorship:Principal investigator  Grant type:Competitive

  18. 時間依存密度汎関数法による炭素系ナノ構造の非平衡電子状態の研究

    2004.4 - 2007.3

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

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    Grant type:Competitive

  19. 時間依存密度汎関数法による炭素系ナノ構造の非平衡電子状態の研究

    Grant number:04J02793  2004 - 2006

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    洗平 昌晃

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    電界電子放射現象はナノスケールの電子源として期待されており,理論・実験ともに精力的に研究されている物理現象である.この現象は強電界・強電流下での量子トンネル現象であり、そのような状況下では放出先端構造が著しい損傷を受けることが実験的に観測されている。このことはナノスケール電子源の寿命と密接な関連を持ち,電界電子放射現象を利用した次世代デバイスの実現に関して非常に重要な問題である.そこで,電界電子放射現象下でのNa原子に働く力をリカージョン伝達行列法(RTM)を用いて研究した.RTM法は電界電子放射現象のみならず,原子架橋系での定常電気伝導の研究にも使われる第一原理計算手法である.
    この研究において,電界電子放射による原子蒸発の閾値電界強度を見積もることができた.その際,蒸発原子は有効的に負に帯電していることを明らかにした.蒸発原子が負に帯電することは,電界電子放射現象を起こす際に印加される電界の向きとは矛盾せず,過去に成された理論研究とも合致している.しかしながら,実際に電流が流れている状況下でこのことを示したのは本研究が初めてである.また,この研究で得られた興味深い知見は,"ポテンシャル曲線から理解される電界電子放射現象下での原子の蒸発メカニズムは,蒸発原子の有効電荷の符号と電界の方向を除けば,通常の電界蒸発現象と同じである",ということである.このことに関しては詳細な研究が行われる必要があるが,この研究は電界電子放射現象下での表面原子過程を理解するための足がかりになるものと考えられる.

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Teaching Experience (On-campus) 21

  1. Physical Science and Engineering Tutorial 2b

    2020

  2. Applied Physics Tutorial II a/II b

    2020

  3. フロンティア計算物理セミナー1A

    2020

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    1年・春学期

  4. フロンティア計算物理セミナー1B

    2020

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    1年・秋学期

  5. フロンティア計算物理セミナー1C

    2020

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    2年・春学期

  6. フロンティア計算物理セミナー1D

    2020

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    2年・秋学期

  7. フロンティア計算物理特別実験及び演習A

    2020

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    2年・秋学期

  8. フロンティア計算物理特別実験及び演習B

    2020

  9. Physical Science and Engineering Tutorial 2b

    2019

  10. Applied Physics Tutorial II a/II b

    2019

  11. Applied Physics Tutorial II

    2018

  12. Physical Science and Engineering Tutorial 2b

    2018

  13. 応用物理学演習第1

    2017

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    学部2年生の演習(電磁気学)

  14. Applied Physics Tutorial II

    2017

  15. Applied Physics Tutorial II

    2016

  16. 応用物理学演習第1

    2016

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    学部2年生の演習(電磁気学)

  17. 応用物理学演習第1

    2015

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    学部2年生の演習(電磁気学)

  18. Applied Physics Tutorial II

    2015

  19. 応用物理学演習第1

    2014

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    学部2年生の演習(電磁気学)

  20. Applied Physics Tutorial II

    2014

  21. 応用物理学演習第2

    2013

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    学部2年生の演習(熱力学)

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Academic Activities 4

  1. EXECUTIVE COMMITTEE of ICMaSS2021 International contribution

    Role(s):Planning, management, etc.

    Institute of Materials and Systems for Sustainability  2020.12

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    Type:Competition, symposium, etc. 

  2. 日本物理学会第75回年次大会実行委員会

    Role(s):Planning, management, etc.

    日本物理学会  2018.12 - 2020.3

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    Type:Academic society, research group, etc. 

  3. EXECUTIVE COMMITTEE of ICMaSS2019 International contribution

    Role(s):Planning, management, etc.

    Institute of Materials and Systems for Sustainability  2018.11 - 2019.12

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    Type:Academic society, research group, etc. 

  4. EXECUTIVE COMMITTEE of ICMaSS2017 International contribution

    Role(s):Planning, management, etc.

    Institute of Materials and Systems for Sustainability  2016.6 - 2017.12

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    Type:Competition, symposium, etc.