Origin of near-band-edge photoluminescence of GaAsN

The emission processes at high energy edge of PL spectra of GaAsN are clarified by the temperature dependence photoluminescence (PL) spectra and time resolved PL spectra. The PL spectra and TR-PL spectra of GaAsN are deconvoluted by three Gaussian functions (P1, P2 and P3 from high energy side). There are three emission processes at high energy edge of PL spectra of GaAsN. The energies of P2 and P3 are ∼6 meV and ∼17 meV lower than that of P1. The integrated intensity of P1 increases with increasing temperature from 4.2K to 50K, while those of the other peaks decrease. From these results, following possibility are suggested: (i) the origin of P1 is band to band transition, (ii) the origin of P2 is caused by free exciton or shallow donor related recombination, and (iii) P3 originate from donor-acceptor pair emission or overlapping of emission which comes from a number of localized states.