Investigation on spontaneous recombination mechanisms in GaN based laser diodes under low injection current

Abstract

This study works on the spontaneous recombination mechanisms of GaN-based laser diodes (LDs) under low injection current by examining their power–current (P–I) curves and electroluminescence spectra. Our investigation focuses on the behavior of differential efficiency in LDs under low injection current, revealing that a competition between impurity-related yellow emissions and band-edge blue emissions leads to a change in total luminescence efficiency. Using both experimental and simulating methods, the yellow emission peak is primarily attributed to carrier recombination in deep-level defects located on the LD's p-side. A detailed explanation to the differential efficiency changing mechanism is beneficial to improve the GaN-based LD performance in future fabrication.