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Control of Na contents in group IV clathrate and their electrical and optical characterizations

Research Project

Project/Area Number 20K03820
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
Research InstitutionGifu University

Principal Investigator

Ohashi Fumitaka  岐阜大学, 工学部, 准教授 (20613087)

Project Period (FY) 2020-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2022: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2021: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2020: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Keywords半導体 / クラスレート / 薄膜 / ナトリウム / IV族系材料 / 電子物性 / 光物性
Outline of Research at the Start

II型IV族クラスレートは、IV族原子(Si、Ge)のsp3結合で形成されるかご状構造を示し、Naなどをかごに内包し、NaxIV136と表される。Naのイオン化により電子が供給されるため、Naの内包量(24 ≧ x ≧ 0)に応じて、金属から半導体へと変化する。NaxIV136は、赤外から可視光領域の直接遷移型のバンドギャップを有することから、光電変換デバイスなどへの応用が期待できる。近年我々のグループでは、実用化に向けて重要な、薄膜合成技術を世界で初めて確立した。本研究では、NaxIV136に含まれるNa量の精密なコントロールと、それによる電子物性・光物性の変化を詳細に調べる。

Outline of Final Research Achievements

Firstly, controls of Na contents and distributions in group IV clathrate films were conducted by applying electric field. Reductions of Na contents in the entire clathrate films were confirmed, however, local reductions of Na contents at the films were not observed. Secondly, the formations of electrodes on the films were conducted. When Ag were used as the electrode material, ohrmic I-V characteristics were appeared while Al showed higher resistance in several order. This is suggesting that Al and Na formed insulating compound between the clathrate and electrode films. The I-V characteristics of clathrate films with reductions of Na contents using a long vacuum annealing showed an increase of current by photo-irradiation. The photo-absorption spectra were analyzed to understand the fundamental absorption edge.

Academic Significance and Societal Importance of the Research Achievements

SiまたはGeがフレームワークを構成するII型クラスレートは、計算結果から直接遷移型半導体であり、その合金化によりバンドギャップを1.2 eVから1.8 eVの間で制御できるとされている。これらの特性により毒性の低いIV元素による、高効率太陽電池や発光素子への応用を期待できる。しかしながら、薄膜化が困難であり、半導体の詳細な物性評価およびデバイス化には至っていない。また、合成時に結晶構造中に内包されるアルカリ金属の除去技術の確立が必要不可欠である。本研究では、クラスレートの物性評価およびデバイス化を目的として、内包Naの除去技術、電極材料の選定、適切な電極材料による半導体物性評価を行った。

Report

(4 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • Research Products

    (16 results)

All 2023 2022 2021 2020

All Journal Article (7 results) (of which Peer Reviewed: 7 results,  Open Access: 4 results) Presentation (9 results) (of which Int'l Joint Research: 1 results)

  • [Journal Article] Optimization of synthesis condition of type II Ge clathrate film2023

    • Author(s)
      Kumar Rahul、Yamada Kohei、Ohashi Fumitaka、Jha Himanshu Shekhar、Kume Tetsuji
    • Journal Title

      Japanese Journal of Applied Physics

      Volume: 62 Issue: SD Pages: SD1020-SD1020

    • DOI

      10.35848/1347-4065/acae2c

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] Synthesis and optical properties of Ge clathrate films with and without Al doping2023

    • Author(s)
      Aye Tun Naing、Kawaura Yuto、Kumar Rahul、Ohashi Fumitaka、Jha Himanshu S.、Kume Tetsuji
    • Journal Title

      Japanese Journal of Applied Physics

      Volume: 62 Issue: SD Pages: SD1018-SD1018

    • DOI

      10.35848/1347-4065/acade8

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed / Open Access
  • [Journal Article] A fabrication method for type-II Ge clathrate film by annealing of Ge film covered with Na layer2021

    • Author(s)
      Kumar Rahul、Hazama Yuta、Ohashi Fumitaka、Jha Himanshu S.、Kume Tetsuji
    • Journal Title

      Thin Solid Films

      Volume: 734 Pages: 138859-138859

    • DOI

      10.1016/j.tsf.2021.138859

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Growth of Si Clathrate Films with Various Annealing Conditions2020

    • Author(s)
      Tanaka K.、Kumar R.、Maeda T.、Ohashi F.、Jha H. S.、Kume T.
    • Journal Title

      Japanese Journal of Applied Physics Conference Proceedings

      Volume: 8 Pages: 011101-011101

    • DOI

      10.7567/jjapcp.8.011101

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Preparation of Guest Free Type?II Si?Ge Clathrate Using Ionic Liquid Method2020

    • Author(s)
      Hisamatsu H.、Yamada K.、Ohashi F.、Jha H. S.、Kume T.
    • Journal Title

      Japanese Journal of Applied Physics Conference Proceedings

      Volume: 8 Pages: 011302-011302

    • DOI

      10.7567/jjapcp.8.011102

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Electron spin resonance, dynamic Jahn-Teller effect, and electric transport mechanism in Na-doped type II silicon clathrates2020

    • Author(s)
      Yamaga Mitsuo、Kishita Takumi、Goto Kouhei、Sunaba Shogo、Kume Tetsuji、Ban Takayuki、Himeno Roto、Ohashi Fumitaka、Nonomura Shuichi
    • Journal Title

      Journal of Physics and Chemistry of Solids

      Volume: 140 Pages: 109358-109358

    • DOI

      10.1016/j.jpcs.2020.109358

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Growth of Ge clathrate on sapphire and optical properties2020

    • Author(s)
      Kumar R.、Maeda T.、Hazama Y.、Ohashi F.、Jha H. S.、Kume T.
    • Journal Title

      Japanese Journal of Applied Physics

      Volume: 59 Issue: SF Pages: SFFC05-SFFC05

    • DOI

      10.35848/1347-4065/ab6e0a

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Presentation] 様々なSiGe原子組成比をもつII型SiGe合金クラスレート薄膜の結晶構造および光学特性評価2023

    • Author(s)
      新谷 明宏、栗田 詩織、大橋 史隆、Jha Himanshu、Kumar Rahul、久米 徹二
    • Organizer
      第70回応用物理学会春季学術講演会
    • Related Report
      2022 Annual Research Report
  • [Presentation] Thin Film Synthesis and Characterizations of Type II SiGe Alloyed Clathrates2022

    • Author(s)
      Shiori Kurita, Ryo Noguchi, Rahul Kumar, Tun Naing Aye, Fumitaka Ohashi, Himanshu S. Jha, Tetsuji Kume
    • Organizer
      nternational Photovoltaic Science and Engineering Conference, PVSEC-33
    • Related Report
      2022 Annual Research Report
    • Int'l Joint Research
  • [Presentation] Optical and Electronic Properties of the Type II Ge Clathrate Film and Effects of Si/Al Doping2022

    • Author(s)
      Rahul Kumar、Shiori Kurita、Tun Naing Aye、Tamio Iida、Hitoe Habuchi、Fumitaka Ohashi、Himanshu S. Jha、Tetsuji Kume
    • Organizer
      The 83rd JSAP Autumn Meeting 2022
    • Related Report
      2022 Annual Research Report
  • [Presentation] Synthesis and Properties of Type II Ge clathrate film on Sapphire Substrate2022

    • Author(s)
      Tun Naing Aye、Yuto Kawaura、Himanshu S. Jha、Fumitaka Ohashi、Tetsuji Kume
    • Organizer
      2022年第69回応用物理学会春期学術講演会
    • Related Report
      2021 Research-status Report
  • [Presentation] Synthesis of Type-II Ge Clathrate Films with Various Film Thickness2021

    • Author(s)
      Rahul Kumar、Tun Naing Aye、Fumitaka Ohashi、Himanshu Shekhar Jha、Tetsuji Kume
    • Organizer
      2021年第82回応用物理学会秋季学術講演会
    • Related Report
      2021 Research-status Report
  • [Presentation] A New Synthesis Technique for type-II Ge Clathrate Film2021

    • Author(s)
      1.Rahul Kumar, Yuta Hazama, Fumitaka Ohashi1, Himanshu Shekhar Jha, Tetsuji Kume
    • Organizer
      第68回応用物理学会春季学術講演会
    • Related Report
      2020 Research-status Report
  • [Presentation] Synthesis of ternary type II clathrate films using AlGe alloy2021

    • Author(s)
      2.Tun Naing Aye, Rahul Kumar, Himanshu Shekhar Jha, Fumitaka Ohashi, Tetsuji Kume
    • Organizer
      第68回応用物理学会春季学術講演会
    • Related Report
      2020 Research-status Report
  • [Presentation] Na内包II型Geクラスレート膜の新規合成方法2020

    • Author(s)
      Rahul Kumar, 大橋 史隆, 山田 航平, Himanshu S. Jha, 久米 徹二
    • Organizer
      第 17 回 「次世代の太陽光発電システム」- 天下統一スタートの地から新たな一歩 -
    • Related Report
      2020 Research-status Report
  • [Presentation] Synthesis of type II clathrate film using AlGe alloy2020

    • Author(s)
      4.Tun Naign Aye, Rahul Kumar, Himanshu, S. Jha, Fumitaka Ohashi, Tetsuji Kume
    • Organizer
      第 17 回 「次世代の太陽光発電システム」- 天下統一スタートの地から新たな一歩 -
    • Related Report
      2020 Research-status Report

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Published: 2020-04-28   Modified: 2024-01-30  

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