Photogenerated carrier dynamics under the influence of electric fields in III-V semiconductors

We present a rigorous analysis of the effects of electric fields on time-resolved photoluminescence spectra in semiconductors. It is based on the solution of the semiconductor transport equations using the drift-diffusion approxmation. The results show that the effect of the field alone on the photoluminescence decay can be distinguished from that of charge separation and field-enhanced surface recombination. The analysis is applied to two different sets of experiments. In the first, we use femtosecond luminescence upconversion to observe the ultrafast charge separation in the space-charge region, and screening of the electric field under high-injection conditions. The second group of experiments was conducted on heterostructures of GaAs/Gaₓ{In}_{1{{-}}x}$P under externally applied bias using time-correlated single-photon counting detection in the picosecond time domain. The use of the method for extracting charge-transfer velocities across semiconductor interfaces is discussed.