Dimensional oscillation in GaAs/AlAs quantum wells by two-dimensional standing surface acoustic waves

We have used spatially and time-resolved photoluminescence (PL) spectroscopy recorded using a synchronized excitation method in order to investigate the mechanisms for the dynamic PL modulation of GaAs/AlAs quantum wells by two-dimensional (2D) standing surface acoustic waves (SAWs). It is clearly demonstrated that a square array of dynamic quantum dots (DQDs) is formed, which oscillates with a repetition interval equal to half of the SAW period. A 2D flatband condition appears between the DQD formations. The spatial modulation of the PL intensity is attributed to exciton migration into the tensile-strained dots created by the strain-induced band-gap modulation. (C) 2007 American Institute of Physics.