Radiative recombination mechanisms of GaAs1−xPx

Dependence of excitation density and temperature of photoluminescence have been used to identify the radiative transitions of GaAS1−xPx in the indirect band-gap region (x = 0.85). At 16 K the spectra consisting of five recombination bands are observed from nitrogen-doped GaAsP. The transitions associated with nitrogen are found to dominate the recombination spectra. One of them is attributed to the recombination of excitons bound to isolated nitrogen atoms (Nx), another one is due to LO-phonon assisted transitions of nx, and the other three are owing to donor-acceptor (DA) and nitrogen pair transitions (NN). By combining the results of the excitation density and temperature dependence of the photoluminescence properties, the transition mechanisms for the luminescence are presented and discussed.