Trap emission rates in GaAs in the presence of surface acoustic waves

Experimental and theoretical analyses of the effects of surface acoustic waves (SAW) on trap emission rates in GaAs are presented. Measurements of electron trap emission rates using deep level transient spectroscopy measurements performed in the presence of SAW are discussed. For the three trapping levels investigated, the observed increases in the trap emission rates can be described by trap activation energies which decrease in direct proportion to the SAW power. A theoretical analysis of the effects of the acoustic strain, electric field, and heating associated with the SAW is also presented. This analysis is used to predict the magnitude and functional dependence of the emission rate enhancement. The theoretical predictions follow the same functional dependence as the experimental data but the predicted magnitudes of the shifts in trap energies are about a factor of 2 lower than the measured values.