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1996 Fiscal Year Final Research Report Summary

Exciton relaxation in chalcogenide semiconductor investigated by time-resolved photoluminescence measurement

Research Project

Project/Area Number 07640445
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 固体物性Ⅰ(光物性・半導体・誘電体)
Research InstitutionOsaka University

Principal Investigator

MATSUDA Osamu  Osaka University, Graduate School of Science, Research Associate, 大学院・理学研究科, 助手 (30239024)

Co-Investigator(Kenkyū-buntansha) INOUE Koichi  Osaka University, The Institute of Scientific and Industrial Research, Assistant, 産業科学研究所, 助教授 (50159977)
Project Period (FY) 1995 – 1996
KeywordsChalcogenide / Amorphous / Crystal / Photoluminescence / Electron-phonon interaction / Relaxation / Time-resolved measurement / Exciton
Research Abstract

Amorphous chalcogenide semiconductors which contain the elements of group VI show various kinds of photo-induced structural changes such as photo-darkening, photo-bleaching, photo-crystallization, etc.. These changes are caused by lattice deformations which result from the relaxation of the photo-excited electrons through the strong electron-phonon interaction. It is also important that the amorphous states are not in the thermal equilibrium. The chalcogen atoms which are in two-fold coordinated are considered to play an important role, but the details of the mechanism is still not clear. For example, it is still unknown how the excited electron distorts the lattice.
To know the relaxation process of the excited electron in the amorphous and crystalline GeSe_2 which is a typical chalcogenide semiconductor, the time resolved photo-luminescence measurement was carried out. Both phases have the band-gap in visible region (2.2-2.7eV). The excitation by band-gap light causes a broad Gaussian-shaped photo-luminescence in near-infra-red region (-1eV). The large Stokes-shift is due to the strong electron-phonon interaction. The continuous wave laser light is modulated by an acousto-optic modulator and then used for the excitation source of the time-resolved measurement. The measured time region was 100ns-3ms after the cut-off of the excitation light. There are many similarities in the spectral shape between the amorphous and crystalline GeSe_2. This result shows that the initial states of the luminescence are similar in both materials. As for the time-profile, the crystalline GeSe_2 shows the single exponential decay, while the amorphous GeSe_2 shows the extended exponential decay. The later is caused by the energy distribution of the luminescent centers by structural fluctuation in the glass.

  • Research Products

    (14 results)

All Other

All Publications (14 results)

  • [Publications] K. Inoue: "A model calculation of the characteristic Raman modes in the tetrahedral network structures of GeSe_2" Physica B. 219 & 220. 520-522 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] O. Matsuda: "Photoemission and inverse-photoemission study on the electronic structure of p-and n-type amorphous Ge-Se-Bi films" Journal of Non-crystalline Solids. 198-200. 688-691 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Wada: "Photoluminescence study on glassy Ge (SxSe_<1-x>)_2" Journal of Non-crystalline Solids. 198-200. 732-735 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M. Nakamura: "Laser spot size dependence of photo-induced crystallization process in amorphous GeSe_2" Journal of Non-crystalline Solids. 198-200. 740-743 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Wang: "Temperature dependence of Raman spectra in amorphous, crystalline, and liqued GeSe_2" Journal of Non-crystalline Solids. 198-200. 753-757 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Wang: "Structure and glass transition in GexSe_<1-x> studued by Ramam Scattering" Proc 23rd International Conference of the Physics of Semiconductors. 153-156 (1996)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y. Wang: "Structural changes of glass transition in GexSe_<1-x> studued by Ramam scattering" Proc. Yukawa International Seminar 1996. (in printing).

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K.Inoue: "A model calculation of the characteristic Raman modes in the tetrahedral network structures of GeSe_2" Physica B. Vol.219&220. 520-522 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] O.Matsuda: "Photoemission and inverse-photoemission study on the electronic structure of p- and n-type amorphous Ge-Se-Bi films" Journal of Non-crystalline Solids. vol.198-200. 688-691 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Wada: "Photoluminescence study on glassy-Ge (S_xSe_<1-x>) _2" Journal of Non-crystalline Solids. vol.198-200. 732-735 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M.Nakamura: "Laser spot size dependence of photo-induced crystallization process in amorphous GeSe_2" Journal of Non-crystalline Solids. vol.198-200. 740-743 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Wang: "Temperature dependence of Raman spectra in amorphous, crystalline, and liquid GeSe_2" Journal of Non-crystalline Solids. vol.198-200. 753-757 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Wang: "Structure and glass-transition in Ge_xSe_<1-x> studied by Raman scattering" Proc.23rd International Conference on the Physics of Semiconductors, Berlin, Germany, eds.W.Scheffler and A.Zimmermann (World Scientific, Singapore). 153-156 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Wang: "Structural changes at glass-transition in Ge_xSe_<1-x> studied by Raman scattering" Proc.Yukawa International Seminar 1996, Dynamics of Glass Transition and Related Topics, Kyoto, Japan, Nov.12-15. (in printing). (1996)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1999-03-09  

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