Room-temperature photoluminescence decay time measurements in heavily doped GaAs:C-layers designed as base layers for heterojunction bipolar transistors are reported. These measurements provide access to nonequilibrium minority carrier lifetimes that determine the current gains of those devices. By systematically studying transient luminescence spectra over a wide range of excitation densities between 10 13 and 10 18 cm Ϫ3 , we demonstrate the importance of carrier trapping processes at low excitation densities. Optimized excitation conditions that achieve trap saturation but also avoid stimulated emission are found for densities of (1-3)ϫ10 17 cm Ϫ3 /pulse. Detection is limited to a spectral window well above the energy gap ͑beyond 1.5 eV͒. Values for both Auger and radiative recombination coefficients are given.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.