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2005 Fiscal Year Final Research Report Summary

Study on photo-induced magnetic transition in II-VI diluted magnetic semiconductor quantum wells with a type band allignment

Research Project

Project/Area Number 15340096
Research Category

Grant-in-Aid for Scientific Research (B)

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

Principal Investigator

NAKAMURA Arao  Nagoya University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (50159068)

Co-Investigator(Kenkyū-buntansha) AKIMOTO Ryoichi  National Institute of Advanced Industrial Science and Technology, Ultrafast Photonic Devices Laboratory, senior researcher, 光技術研究部門, 主任研究員 (30356349)
Project Period (FY) 2003 – 2005
KeywordsType II quantum wells / Diluted magnetic semiconductors / Magnetic exchange interaction / Two-dimensional excitons / Band off-set / Interfaces of quantum wells / Scanning tunneling microscopy / Anomalus Hall effects
Research Abstract

1. Preparation of p-type ZnSe/BeMnTe quantum well structures
ZnSe/N-doped BeMnTe quantum wells and N-doped BeMnTe thin films were grown on GaAs substrates by a molecular beam epitaxy method. The hole carrier density in the range of 10^<18>-10^<19> cm^<-3>, which corresponds to the carrier density necessary for carrier-induced ferrpmagnetism, was obtained at the temperatures between 2 and 300 K.
2. Analysis of cross-sectional structure of ZnSe/BeTe quantum well interfaces
Carrier lifetimes and overlapping of electron and hole wave functions strongly depend on the interfacial quality, because the recombination between electrons and holes takes place at the interfaces in the quantum wells with a type II band alignment. We investigated sharpness and alloy effects at the interfaces between ZnSe and BeTe layers in the multiple quantum wells using cross-sectional scanning tunneling microscopy and X-ray diffraction measurements. The filled- and empty-state images revealed that Zn-Te and Be-Se bon … More ds exist at the ZnSe/BeTe interface within the range of 2-4 monolayers along the growth direction. The transition layer between the ZnSe layer and the BeTe layer is composed of the BeZnSeTe quaternary alloy corresponding to (ZnTe)_<0.58>(BeSe)_<0.42>.
3. Observation of anomalus Hall effects and ferromagnetic transition
We measured anomalus Hall effects in N-doped Be_<1-x>Mn_xTe (x=0.05 and 0.10), and found that Be_<1-x>Mn_xTe is ferromagentic at the temperature lower than 10 K. Negative magnetoresistance and its hysterisis behavior were observed for the first time for Be_<1-x>Mn_xTe, which confirmed the carrierd-induced ferromagnetism. The observation of the Hall effect with the high magnetic field supported that the observed negative magnetoresistance is due to free carrier generation from bound magnetic polarons by the applied magnetic field.
4. Luminescence properties of ZnSe/BeMnTe quatum well structures
We investigated effects of applied electric and magnetic fields on luminescence properties, and found that the luminescence at the interfaces is enhanced and reduced by the applied-electric field. However, we could not observe a sharp luminescence band in the highly N-doped ZnSe/BeMnTe quantum well because of the interfacial roughness at the heterojunctions. Less

  • Research Products

    (7 results)

All 2006 2005

All Journal Article (7 results)

  • [Journal Article] ZnSe interlayer effects on properties of (CdS/ZnSe)/BeTe superlattices grown by molecular beam epitaxy2006

    • Author(s)
      B.S.Li, R.Akimoto, K.Akita, T.Hasama
    • Journal Title

      Journal of Applied Physics 99

      Pages: 044912

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Electric-and magnetic-field effects on radiative recombination in modulation n-doped ZnSe/BeTe type-II quantum wells2006

    • Author(s)
      Z.Ji, H.Mino, K.Oto, R.Akimoto, K.Ono, S.Takeyama
    • Journal Title

      Semicond. Sci. Technol. 21・1

      Pages: 87

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Electric- and magnetic-field effects on radiative recombination inmodulation n-doped ZnSe/BeTe type-II quantum wells2006

    • Author(s)
      Z.Ji, H.Mino, K.Oto, R.Akimoto, K.Ono, S.Takeyama
    • Journal Title

      Semiconductor Science and Technology 21(1)

      Pages: 87

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Scanning-tunneling-microscopy observation of heterojunctions with a type-II band alignment in ZnSe/BeTe multiple quantum wells2005

    • Author(s)
      I.Yamakawa, Y.Akanuma, R.Akimoto, A.Nakamura
    • Journal Title

      Applied Physics Lettters 86

      Pages: 153112

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Composition profile of ZnSe/BeTe multiple quantum well structures studied by cross-sectional scanning tunneling microscopy2005

    • Author(s)
      I.Yamakawa, Y.Akanuma, B.S.Li, R.Akimoto, A.Nakamura
    • Journal Title

      Japanese Journal of Applied Physics 44・43

      Pages: L1337-L1340

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Scanning-tunneling-microscopy observation of hetero-junctions with a type-II band alignment in ZnSe/BeTe multiple quantum wells2005

    • Author(s)
      I.Yamakawa, Y.Akanuma, R.Akimoto, A.Nakamura
    • Journal Title

      Applied Physics Letters 86

      Pages: 153112

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Composition profile of ZnSe/BeTe multiple quantum well structures studied by cross-sectional scanning tunneling microscopy2005

    • Author(s)
      I.Yamakawa, Y.Akanuma, B.S.Li, R.Akimoto, A.Nakamura
    • Journal Title

      Japanese Journal of Applied Physics 44(43)

      Pages: L1337-L1340

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

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Published: 2007-12-13  

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