Interpretation of an anomalous peak in low-temperature photoluminescence measurements of bulk GaAs1-xNx on GaAs

Abstract

Low-temperature (10 K) photoluminescence measurements of Ga As1-x Nx epitaxial layers grown on GaAs reveal an anomalous second peak in solid-source molecular beam epitaxy. Rapid thermal annealing (RTA) of a specific GaAsN sample reveals a lower energy peak (γ) which redshifts and a higher energy peak (α) which blueshifts under increasing annealing temperature. The band-anticrossing model is used to identify the origins of the two peaks and we propose a model to explain the RTA observations by the concept of increased confinement in areas of higher N concentrations by trapped N localized states. The γ peak is due to the accumulation of N content near the GaAsGaAsN interface. Hence, this abnormal annealing behavior occurs in layers with nonuniform N concentration at the GaAsNGaAs interface. © 2006 American Institute of Physics.