Temperature and excitation power dependence of the optical properties of InAs self-assembled quantum dots grown between two Al0.5Ga0.5As confining layers

We have investigated the temperature and excitation power dependence of pho toluminescence properties of InAs self-assembled quantum dots grown between two Al0.5Ga0.5As quantum wells. The temperature evolutions of the lower-an d higher-energy transition in the photoluminescence spectra have been obser ved. The striking result is that a higher-energy peak appears at 105 K and its relative intensity increases with temperature in the 105-291 K range. W e demonstrate that the higher-energy peak corresponds to the excited-state transition involving the bound-electron state of quantum dots and the two-d imensional hole continuum of wetting layer. At higher temperature, the carr ier transition associated with the wetting layer dominates the photolumines cence spectra. A thermalization model is given to explain the process of ho le thermal transfer between wetting layer and quantum dots. (C) 2000 Publis hed by Elsevier Science B.V. All rights reserved.