Piezoelectric-induced quantum-confined Stark effect in self-assembled InAsquantum dots grown on (N11) GaAs substrates

We investigate the optical properties of InAs self-assembled quantum dots g rown on (N11)A/B GaAs substrates, by means of cw photoluminescence under di fferent excitation power densities. We observe a sizeable blue-shift of pho toluminescence band induced by increasing the photogenerated carrier densit y. The shift depends on the substrate orientation and exhibits a strong asy mmetric dependence on the substrate termination. We attribute the photolumi nescence blue-shift to a reverse quantum confined Stark shift of ground sta te transition energies in the quantum dots. This effect arises from the pho togenerated charge screening of the built-in piezoelectric field present in such strained structures grown on high index planes. (C) 2000 American Ins titute of Physics. [S0003-6951(00)04738-0].