Systematic studies on optical gain spectra in GaInN/GaN-MQWs

Abstract The origin of optical gain in Ga 1− x In x N/GaN multiple quantum wells with x =0.05, 0.10 and 0.16 was investigated systematically by using a variable excitation-stripe method under various excitation conditions, such as power density and temperature. It was found that the alloy inhomogeneity of In content increases the width of the gain spectrum and decreases its value. It is supposed that the stimulated emission observed at the high-energy end of spontaneous emission spectrum originates from the optical gain due to electron–hole plasma around the mobility edge for all the samples.