Threshold characteristics of blue to ultraviolet light emitting semiconductor lasers based on the AlGaN material system

Two-dimensional numerical simulations of AlGaN/GaN/AlGaN semiconductor lasers are performed using material parameters obtained from the literature. Important differences between these wide band gap lasers and lasers from other systems are the slow recombination rate and large band discontinuities. The behavior of the threshold, and thus the speed of operation, with variations in the aluminum content of the cladding regions, and the width of the active region are presented. Results for lasing due to band to band recombination and band to impurity level recombination are presented separately. From these we observe that the band to impurity recombination is difficult due to the reduced number of available states for recombination. Stopper layers are investigated and found to be useful at increasing carrier confinement without any detrimental effects because particle tunneling is very strong for majority carriers through the band discontinuities.