Photoluminescence study of in situ annealed InAs quantum dots:: Double-peak emission associated with bimodal size distribution

We report a photoluminescence study of self-assembled InAs islands subjected to in situ annealing prior to the growth of a capping layer. A distinctive double-peak feature is observed in the photoluminescence spectra of annealed samples. The power dependence of the photoluminescence spectra reveals that the double-peak emission is associated with the ground-state transition of islands in two different size branches. This observation agrees with a previous study, which demonstrated that the InAs island size distribution bifurcates during post-growth annealing. The temperature dependence of the photoluminescence intensities from samples with bimodal island size distributions illustrates that different thermal activation energies for carrier emission are associated with islands in different size branches. (C) 1998 American Institute of Physics. [S0003-6951(98)03050-2].