A Systematic Study of Spin‐Dependent Recombination in GaAs1−xNx as a Function of Nitrogen Content

Abstract

A systematic study of spin‐dependent recombination (SDR) under steady‐state optical pumping conditions as a function of nitrogen content, x, in dilute nitride alloys of the form GaAs1−xNx is reported. Use of high‐excitation power densities up to 107 W cm−2 allows measurement of the full SDR versus power curves, even at relatively high nitrogen contents of x = 0.039. Alloy contents for are determined within by fitting the photoluminescence (PL) spectra using a Roosbroeck–Shockley relation, and values consistent with those obtained by studying the intensity of the GaN‐like LO2 Raman mode are found. PL intensity increases by a factor known as the SDR ratio when switching from linearly to circularly polarized pump excitation. This factor reaches 5 for x = 0.022 and decreases with increasing x, falling to 1.5 for x = 0.039. Moreover, the excitation power required for maximum SDR increases with increasing x, varying from 0.6 mW for x = 0.022 to 15 mW for x = 0.039. These observations indicate an increase in the density of electronically active defects with increasing nitrogen content, both responsible for the SDR and other, standard Shockley–Read–Hall centers. The result demonstrates the importance of including nonspin‐dependent recombination channels in a complete model of SDR.