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Study on photogenerated carriers and their relation with novel photoinduced properties of transition-metal oxides

Research Project

Project/Area Number 17540298
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Condensed matter physics I
Research InstitutionWakayama University

Principal Investigator

ITOH Chihiro  Wakayama University, Faculty of Systems Engineering, Professor (60211744)

Co-Investigator(Kenkyū-buntansha) KIDA Hirotsugu  Wakayama University, Faculty of Systems Engineering, Associate Professor (30186275)
Project Period (FY) 2005 – 2007
Project Status Completed (Fiscal Year 2007)
Budget Amount *help
¥3,640,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥240,000)
Fiscal Year 2007: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2006: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywordsphotogenerated carriers / numn mrobe-interferometry / steady state photoconductivity / Strontium Titanate / anatase / lead tangstate / 飛行時間型過渡光伝導測定 / ゾルゲル法 / SiO_2 / TiO_2コンポジット薄膜 / フェムト秒レーザ励起発光測定 / 交流光伝導測定 / フェムト秒時間分解干渉法 / 光ホール効果
Research Abstract

We have studied properties of photogenerated carriers in transition-metal oxides such as strontium titanate (SrTiO_3), anatase type crystal of titanium dioxide (a-TiO_2), and lead tungstate (PbWO_4) by means of fs-time-resolved interferometry and photoconductivity measurements. We obtained following results:
(1) Pump-probe interferometric study revealed that the photogenerated carriers in SrTiO_3 are free at 4 K. The lifetime of the carriers was much longer than 80 ps, which is the time separation between the probe pulse pair for detecting phase shift induced by the pump pulse. The extraordinary long lifetime is compatible with large drift mobility obtained by the time-of-flight transient photoconductivity measurement.
(2) We found that the photocurrent of PbWO_4 was resolved into two components with considering its temperature dependence. The excitation spectrum of the component related to the intrinsic carriers showed a peak at 4.15 eV and a rise around 4.7 eV. These structures are presumably ascribed to the excitonic and the direct band-to-band transitions. However, the excitation spectrum of the carriers thermally released from trapped states shows a peak at 4.12 eV. The excitation spectrum of the latter component is identical to that of the G (II) luminescence.
(3) Photocurrent measurement with using a sample sandwiched by transparent blocking electrodes revealed that the excitation spectrum of the photoinduced charge showed a peak at3.9 eV, as well as the 4.1 eV peak found by the ordinary photoconductivity measurement.
(4) Photoinduced AC conductivity measurements revealed that photocurrent of a-TiO_2 was composed from frequency-independent (DC) and frequency-dependent (AC) components. The AC component showed power low dependence on the field frequency. While the DC component is arising from free carries, the AC component is conceivably due to polarons. The DC component was excited efficiently above 3.4 eV, which is much larger than the band-gap energy of a-TiO_2.

Report

(4 results)
  • 2007 Annual Research Report   Final Research Report Summary
  • 2006 Annual Research Report
  • 2005 Annual Research Report
  • Research Products

    (22 results)

All 2007 2006 2005 2004

All Journal Article (12 results) (of which Peer Reviewed: 3 results) Presentation (10 results)

  • [Journal Article] Temperature dependence of the photocurrent excited above the fundamental absorption edge of PbWO_42006

    • Author(s)
      C. Itoh and S. Kigoshi
    • Journal Title

      phys. slat. sol. (a) 203

      Pages: 3774-3780

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Temperature dependence of the photocurrent excited above the fundamental absorption edge of PbWOI2006

    • Author(s)
      C. Itoh, S. Kigoshi
    • Journal Title

      phys. stat sol.(a) 203

      Pages: 3774-3780

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] Temperature dependence of the photocurrent excited above the fundamental absorption edge of PbWO_42006

    • Author(s)
      C.Itoh, S.Kigoshi
    • Journal Title

      phys. stat. sol. (a) 203

      Pages: 3774-3780

    • Related Report
      2006 Annual Research Report
  • [Journal Article] FT-IR study of photo-induced phase transition in organiccharge-transfer crystal of TTF-CA2006

    • Author(s)
      C.Itoh, S.Fukuda
    • Journal Title

      phys. stat. sol. (c) 3

      Pages: 3446-3451

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Electric field-induced retardation of the drift mobility of the photocarriers in SrTiO_3 crystal2005

    • Author(s)
      C. Itoh, M. Sasabe, H, Kida, and K. Kan'no
    • Journal Title

      J. Luminescence 112

      Pages: 263-266

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Relaxation of photogenerated carriers in the anatase form of crystalline titanium dioxide2005

    • Author(s)
      C. Itoh and A. Wada
    • Journal Title

      physica status solidi (c) 2

      Pages: 629-632

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Electric field-induced retardation of the drift mobility of the photocarriers in SrTiO3 crystal2005

    • Author(s)
      C. Itoh, M, Sasabe, H, Kida, K. Kan'no
    • Journal Title

      J. Luminescence 112

      Pages: 263-266

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] Relaxation of photogenerated carriers in the anatase form of crystalline titanium dioxide2005

    • Author(s)
      C. Itoh, A. Wada
    • Journal Title

      physica status solidi(c) 2

      Pages: 629-632

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] Electric field-induced retardation of the drift mobility of the photocarriers in SrTiO_3 crystal2005

    • Author(s)
      C.Itoh, M.Sasabe, H, Kida, K.Kan'no
    • Journal Title

      J.Luminescence 112

      Pages: 263-266

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Relaxation of photogenerated carriers in the anatase form of crystalline titanium dioxide2005

    • Author(s)
      C.Itoh, A.Wada
    • Journal Title

      physica status solidi (c) 2

      Pages: 629-632

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Ti_4O_7の金属絶縁体転移におけるバイポーラロンの光学応答2005

    • Author(s)
      上野若菜, 渡辺雅之, 林哲介, 伊東千尋
    • Journal Title

      光物性研究会論文集 第16巻

      Pages: 231-234

    • Related Report
      2005 Annual Research Report
  • [Journal Article] CuIr_2S_4単結晶の絶縁体相における光キャリア生成2005

    • Author(s)
      辻本篤, 伊東千尋, 石橋広記
    • Journal Title

      光物性研究会論文集 第16巻

      Pages: 381-384

    • Related Report
      2005 Annual Research Report
  • [Presentation] ゾルゲル法を用いて作製したSiO_2-TiO_2薄膜の光伝導特性2007

    • Author(s)
      平井ゆかり、伊東千尋
    • Organizer
      第18回光物性研究会
    • Place of Presentation
      大阪市立大学
    • Year and Date
      2007-12-08
    • Related Report
      2007 Annual Research Report
  • [Presentation] ポリジアセチレンPDA-DFPCにおける定常光励起誘起色相転移2007

    • Author(s)
      小門亮介、伊東千尋
    • Organizer
      第18回光物性研究会
    • Place of Presentation
      大阪市立大学
    • Year and Date
      2007-12-08
    • Related Report
      2007 Annual Research Report
  • [Presentation] Structural change of single-walled carbon nanotube induced by soft X-ray irradiation2007

    • Author(s)
      C. Itoh, et. al.
    • Organizer
      The 18th International Conference on Radiation Effects in Insulators 2007
    • Place of Presentation
      Caen, France
    • Year and Date
      2007-08-28
    • Related Report
      2007 Annual Research Report
  • [Presentation] ゾルゲル法を用いて作製したSiO_2-TiO_2薄膜の光伝導特性2007

    • Author(s)
      平井ゆかり、伊東千尋
    • Organizer
      第18回光物性研究会
    • Place of Presentation
      大阪市大
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Ti_4O_7における金属絶縁体転移と光学応答の変化32006

    • Author(s)
      上野若菜, 渡辺雅之, 林哲介, 伊東千尋
    • Organizer
      日本物理学会
    • Place of Presentation
      愛媛大学
    • Year and Date
      2006-03-26
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Ti_4O_7の金属絶縁体転移におけるバイポーラロンの光学応答2006

    • Author(s)
      上野若菜, 渡辺雅之, 林哲介, 伊東千尋
    • Organizer
      第16回光物性研究会
    • Place of Presentation
      大阪市大
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] ルチル型二酸化チタン結晶における電場に依存した光伝導2005

    • Author(s)
      伊東千尋, 篠部光義
    • Organizer
      日本物理学会
    • Place of Presentation
      同志杜大学京田辺キャンパス
    • Year and Date
      2005-09-19
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Ti_4O_7における金属絶縁体転移のFTIR・ラマン分光2005

    • Author(s)
      渡辺雅之, 上野若菜, 林哲介, 伊東千尋
    • Organizer
      日本物理学会
    • Place of Presentation
      同志社大学京田辺キャンパス
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Electric field-induced retardation of the drift mobility of the photocarriers in SrTiO3 crystal2004

    • Author(s)
      C. Itoh, M. Sasabe, H, Kida, K. Kan'no
    • Organizer
      6th Int. Conf. on Excitonic Processes in Condensed Mater(EXCON'04)
    • Place of Presentation
      Cracow, POLAND
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Relaxation of photogenerated carriers in the anatase form of crystalline titanium dioxide2004

    • Author(s)
      C. Itoh, A. Wada
    • Organizer
      15th Int. Conf. on Defects in Insulating Materials (ICDIM2004)
    • Place of Presentation
      Riga, LATVIA
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary

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Published: 2005-04-01   Modified: 2020-05-15  

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