Arsenic pressure dependence of carrier lifetime and annealing dynamics for low-temperature grown GaAs studied by pump–probe spectroscopy

Reflection-type degenerate pump-probe spectroscopy was performed for low-temperature grown (LT-) GaAs to study the effects of arsenic pressure during crystal growth and annealing on carrier lifetime and to ascertain the annealing dynamics. It was found that a sample grown under a high arsenic pressure has a shorter carrier lifetime for both as-grown and anneal conditions. It was also found that the carrier decay times of samples changed drastically when the annealing temperature was above 550 °C. We determined the annealing dynamics of LT-GaAs based on a model in which As_Ga antisite defects trap photoexcited carriers. An Arrhenius plot of the carrier decay rate vs. annealing temperature in the high temperature regime gave an energy E_PA that was different from the true activation energy. The annealing time dependences of E_PA obtained by the two diffusion models (self diffusion and V_Ga vacancy assisted diffusion of defects) were compared with E_PAs of our data and other works, which proved that the annealing dynamics of As_Ga antisite defects was dominated by V_Ga vacancy assisted diffusion. © 2003 American Institute of Physics.