Dependence of the carrier lifetime on acceptor concentration in GaAs grownat low-temperature under different growth and annealing conditions

Using the transient reflectivity technique, we have measured the carrier li fetime in low-temperature-grown GaAs (LT-GaAs) samples as a function of gro wth temperature and annealing conditions. We confirm the role of the deep d onor as the dominant nonradiative recombination center, but we show here th at the acceptor concentration is equally crucial for the determination of t he carrier lifetime as the deep donor concentration. Using the number of ac ceptors as the only adjustable parameter in our model, we are able to simul ate the carrier lifetime for the growth and annealing conditions used in ou r experiments and to reproduce all the characteristics of the carrier recom bination dynamics in LT-GaAs, such as nonexponential transients and the inf luence of the illumination intensity. The implications for the use of LT-Ga As for optoelectronic applications are discussed. (C) 2000 American Institu te of Physics. [S0021-8979(00)00408-4].