Development of continuum states in photoluminescence of self-assembled InGaAs/GaAs quantum dots

Crossed transitions between the wetting layer valence band and the quantum dot (QD) electron states are revealed in the photoluminescence from self-assembled In0.4Ga0.6As/GaAs QDs. The strength of these transitions becomes comparable with the excitonic transitions for below-GaAs barrier excitation and decreases significantly with below wetting layer excitation. The observed peculiar QD photoluminescence dependences on temperature and excitation density are due partly to interdot carrier transfer through the continuum states related to the wetting layer morphology and to phonon-assisted processes. (c) 2007 American Institute of Physics.