A low-temperature photoluminescence study of GaAs1-xNx/GaAs multiple quantum wells

Abstract

Five-period GaAs 1−x N x /GaAs multiple quantum wells (MQWs) were grown on GaAs(001) substrates under different nitrogen background pressures through solid-source molecular beam epitaxy and the structural and optical properties at low temperature were investigated. High resolution x-ray diffraction revealed sharper satellite peaks observed for GaAs 0.978 N 0.022 /GaAs MQWs as compared to GaAs 0.982 N 0.018 /GaAs MQWs, indicating better interfaces. The MQWs with higher nitrogen content exhibited high photoluminescence (PL) intensity, whereas a degraded PL intensity was observed for the latter, attributed to reduction in surface recombination with high nitrogen incorporation. Moreover, the spectrum for the MQWs with higher nitrogen content was observed to be consisted of several Gaussian spectra, indicating thickness variation of QWs caused by randomness in distribution of N atoms. In the low energy regime of PL, a long asymmetric tail was observed because of nitrogen introduced potential fluctuations. Rapid thermal annealing enhanced PL intensity by multi-fold and substantially reduced the full width at maximum because of homogenization of MQWs. This investigation could enhance understandings of the MQWs-based optoelectronic devices.