Ultrafast electron and hole trapping times and defect band saturation dynamics in low-temperature-grown GaAs

Summary form only given. Low-temperature-grown GaAs (LT-GaAs) has long been known to have a (sub)picosecond photo-excited carrier response time. In this paper we report the first direct measurement of the hole trapping time from the valence band in LT-GaAs, and distinguish it from electron trapping time from the conduction band and recombination time. These results are compared with trapping and recombination times in conventional semi-insulating GaAs. We have also performed novel experiments at very high optical excitation densities (10/sup 19-20/ carriers/cm/sup 3/) to time resolve the saturation dynamics of mid-gap states.