Spatially resolved photoluminescence in quantum wells with surface acoustic waves

The interaction between a standing surface acoustic wave (SAW) and photogen erated carriers in GaAs/AL(0.3)Ga(0.7)As quantum well (QW) structures is in vestigated using spatially resolved micro-photoluminescence (mu-PL). Under a standing SAW, the mu-PL intensity becomes spatially modulated with a peri od equal to half of the SAW wavelength. The modulation is attributed to (i) the lateral separation of electron-hole pairs by the standing wave potenti al, at times when the piezoelectric potential is large, and (ii) to the pre ferential recombination of the carriers close to the potential nodes, when the standing wave potential vanishes.