Optical Gain Calculation of Wurtzite GaN/AlGaN Quantum Well Laser

Abstract

Optical gain properties of wurtzite GaN/Al_0.2Ga_0.8N quantum well lasers are theoretically analyzed using physical parameters from ab initio calculations for the first time. The valence band of wurtzite GaN exhibits strong non-paraboticity, and the hole density of states is significantly large in comparison with the conventional zincblende crystals. This valence band feature causes high transparency cartier density of 7.5×10¹⁸ cm^-3 in the 50 Å thick GaN quantum well. This result predicts that the threshold current of wurtzite GaN/AlGaN quantum well laser is higher than the conventional lasers with zincblende crystals.