Modeling of carrier lifetimes in uniaxially strained GaAs

Abstract

A carrier dynamics model based on the continuity equation is constructed for doped GaAs in order to explain lifetime changes under uniaxial strain. The model includes detailed expressions of carrier generation, diffusion, recombination, and trapping processes and is solved numerically for fitting carrier decays obtained from time- and spectral-resolved photoluminescence measurements. First, a set of baseline model parameters is established at ambient conditions by fitting experimental data from a GaAs wafer at different excitations. Then, the parameters are adjusted to model carrier lifetimes detected in the samples cut from the same wafer, under the conditions of uniaxial strain applied along the [100] crystallographic orientation. It is shown that the observed linear reduction of effective lifetimes is dominated by the changes in recombination processes. Increase in the strength of the non-radiative Shockley-Read-Hall recombination mechanism versus the radiative band-to-band recombination mechanism is consistent with the quantum efficiency loss in GaAs at increasing uniaxial strain.