Effectively Confining the Lateral Current Within the Aperture for GaN Based VCSELs by Using a Reverse Biased NP Junction

GaN-based vertical cavity surface emitting laser (VCSEL) features the quasi-vertical architecture, and thus a poor lateral current can be encountered, which can significantly reduce the net modal gain and decrease the lasing power. To prevent the holes from lateral leaking outside of the aperture region, we propose GaN based VCSELs with an NP-GaN structure below the buried insulator layer. The reverse biased NP-GaN junction can produce energy barrier that can better suppress the lateral hole leakage outside of the aperture, therefore the better stimulated radiative rate and device lasing power are obtained. Moreover, we also conduct parametric study regarding the impact of different NP-GaN junction designs with various doping concentrations and architectural sizes for the p-GaN layer on the lateral hole confinement capability.