Published January 1, 2018 | Version v1
Journal article Open

Exciton localization and structural disorder of GaAs1-xBix/GaAs quantum wells grown by molecular beam epitaxy on (311)B GaAs substrates

  • 1. Univ Fed Sao Carlos, Dept Fis, BR-13565905 Sao Carlos, SP, Brazil
  • 2. Tampere Univ Technol, Optoelect Res Ctr, POB 692, FI-33101 Tampere, Finland
  • 3. Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England
  • 4. Adana Sci & Technol Univ, Engn & Nat Sci Fac, Dept Mat Engn, TR-01250 Adana, Turkey
  • 5. Univ Sao Paulo, Fac Zootecnia & Engn Alimentos, Dept Ciencias Basicas, BR-13635900 Pirassununga, SP, Brazil
  • 6. Univ Fed Sao Carlos, Dept Engn Eletr, BR-13565905 Sao Carlos, SP, Brazil

Description

In this work, we have investigated the structural and optical properties of GaAs(1-x)Bix/GaAs single quantum wells (QWs) grown by molecular beam epitaxy on GaAs (311)B substrates using x-ray diffraction, atomic force microscopy, Fourier-transform Raman (FT-Raman) and photoluminescence spectroscopy techniques. The FT-Raman results revealed a decrease of the relative intensity ratio of transverse and longitudinal optical modes with the increase of Bi concentration, which indicates a reduction of the structural disorder with increasing Bi incorporation. In addition, the PL results show an enhancement of the optical efficiency of the structures as the Bi concentration is increased due to important effects of exciton localization related to Bi defects, nonradiative centers and alloy disorder. These results provide evidence that Bi is incorporated effectively into the QW region. Finally, the temperature dependence of the PL spectra has evidenced two distinct types of defects related to the Bi incorporation, namely Bi clusters and pairs, and alloy disorder and potential fluctuation.

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