A pump-probe study was made of samples grown by using molecular beam epitaxy at low temperatures. The carrier lifetimes of as-grown low-temperature material increased from less than 0.13ps (measurement limitation) to 1.8ps as the growth temperature was increased from 200 to 320C. The carrier lifetime was found to be approximately inversely proportional to the antisite defect concentration. This trend was in reasonably good agreement with the Shockley-Read-Hall model. A decreasing trend in the amplitudes of continuous-wave and transient reflectivities, as a function of growth temperature, was explained as being an induced absorption caused by dense As antisite defects. The sign of the transient was reversed for low-temperature GaAs grown at 200C. This was tentatively attributed to the band-gap renormalization effect.

Correlation between Defect Concentration and Carrier Lifetime of GaAs Grown by Molecular Beam Epitaxy at Different Temperatures. G.R.Lin, T.A.Liu, C.L.Pan: Japanese Journal of Applied Physics - 1, 2001, 40[11], 6239-42