Photoluminescence properties of nitrogen-doped ZnSe grown by molecular beam epitaxy

Abstract

Nitrogen-doped ZnSe layers (∼0.5 μm thick) have been grown by molecular beam epitaxy (MBE) onto (100)-oriented GaAs substates using both N2 and NH3 gas sources as alternative sources of nitrogen. The low-temperature photoluminescence spectra obtained from N-doped ZnSe layers were dominated by strong donor-acceptor (D-A) pair recombination emission. A no-phonon emission peak (QN0 ) at 2.699 eV together with four distinct longitudinal optical (LO) phonon replicas of QN0 were readily resolved. The amplitudes of this series of D-A pair recombination peaks were found to increase in a monotonic fashion with increasing overpressure of N2 and NH3 in the MBE growth chamber. In addition an acceptor-bound exciton peak (IN1 ) was detected at 2.7917 eV from layers grown using large N2 or NH3 overpressures (∼10−4 mbar.).