Performance improvement of GaN-based microdisk lasers by using a PEALD-SiO<sub>2</sub> passivation layer
Hanru Zhao, Meixin Feng, Jianxun Liu, Xiujian Sun, Yongjian Li, Xunfei Wu, Qifa Liu, Ercan Yılmaz, Qian Sun, Hui Yang
Abstract
Dry-etching is often utilized to shape GaN-based materials. However, it inevitably causes plenty of sidewall defects as non-radiative recombination centers and charge traps that deteriorate GaN-based device performance. In this study, the effects of dielectric films deposited by plasma-enhanced atomic layer deposition (PEALD) and plasma-enhanced chemical vapor deposition (PECVD) on GaN-based microdisk laser performance were both investigated. The results demonstrated that the PEALD-SiO 2 passivation layer largely reduced the trap-state density and increased the non-radiative recombination lifetime, thus leading to the significantly decreased threshold current, notably enhanced luminescence efficiency and smaller size dependence of GaN-based microdisk lasers as compared with the PECVD-Si 3 N 4 passivation layer.