Radiative recombination during acoustically induced transport in GaAs quantum wells

We investigate the dynamics of radiative trapping centers during the ambipolar transport of electrons and holes induced by acoustic fields. The studies used spatially resolved photoluminescence, spectroscopy to determine the nature of the trapping centers for different transport conditions. For low and moderate acoustic powers, the primary traps are electron capturing centers while hole trapping becomes important for high acoustic powers. A remarkable feature of these radiative trapping centers is that their capture cross section depends on the acoustic power. We propose a model for electron trapping based on the injection of carriers induced by the surface acoustic wave piezoelectric field into states at the interface between the GaAs quantum well and the (Al,Ga)As barriers. (c) 2006 American Vacuum Society.