Stokes shift in quantum wells: trapping versus thermalization

Authors:
  • APA. Polimeni
    A. Polimeni
  • APA. Patanè
    A. Patanè
  • MAM. Grassi Alessi
    M. Grassi Alessi
  • MCM. Capizzi
    M. Capizzi
  • FMF. Martelli
    F. Martelli
  • ABA. Bosacchi
    A. Bosacchi
  • SFS. Franchi
    S. Franchi
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Abstract
Low temperature photoluminescence and photoluminescence excitation measurements have been performed in a set of InGaAs/GaAs samples with different indium molar fraction, well width, growth conditions and post-growth treatment. This has allowed to change in a controlled way the degree and source of disorder in the samples, thus resulting in an excitonic absorption linewidth varying between 1 and 18 meV, and an ensueing Stokes shift changing between zero and 8 meV. The conditions of validity of two different models relating the Stokes shift to the linewidth broadening have been established in terms of different regimes of disorder and temperature. A continuous transition between those regimes has been demonstrated.