Exciton transfer at low temperature in GaxIn1-xP:N and GaAs1-xPx:N

The time-resolved luminescence of excitons bound to isolated nitrogen traps in GaxIn1-xP (x0.96) has been investigated under resonant and above-the-band-gap picosecond laser excitation at T=5 K. We observe the dynamics of exciton tunneling both between and within the two main bands Nx and A0 seen in the alloy spectra. The results are a direct proof of the very efficient transfer which occurs for excitons bounds to isolated nitrogen atoms surrounded by four Ga near neighbors (Nx band) to nitrogen atoms with a three-Ga one-In environment (A0 band). An analytic model for these transfer mechanisms fits the measured time evolution of the luminescence spectra for GaxIn1-xP. The same model also describes previously published data for GaAs1-xPx. © 1985 The American Physical Society.