Photoluminescence kinetics in GaAs under the influence of surface acousticwaves

The kinetics of the low-temperature photoluminescence (PL) of GaAs under th e influence of the electric field of a surface acoustic wave (SAW) is inves tigated experimentally. When a SAW pulse (delayed by 20-30 mus with respect to the laser pulse) with a field strength of up to similar to 50 V/cm is a pplied, the rate of the conduction band-to-acceptor transitions increases c onsiderably (by a factor of up to 10-20), while the rate of the donor-accep tor pair transitions does not vary significantly nor is the excitonic PL en hanced. The data obtained provide evidence of shallow-level donor ionizatio n by the SAW electric field and corroborate the recombination model propose d previously, which explains the slow nonexponential decay of the free-elec tron PL in pure GaAs by the effect of multiply repeated capture of free con duction-band electrons by shallow-level donors. (C) 2001 MAIK "Nauka/Interp eriodica".