High‐Power GaN‐Based Blue Laser Diodes Degradation Investigation and Anti‐aging Solution

Abstract

Gallium nitride (GaN)‐based semiconductor laser diodes (LDs) have garnered significant attention due to their promising applications. However, high‐power LDs face serious degradation issues that limit their practical use. This study investigates the degradation factors of 437 nm and 6.3 W LDs by comparing light–current–voltage (L–I–V) characteristics, transmission electron microscopy (TEM), cathodoluminescence (CL), and secondary ion mass spectroscopy (SIMS) before and after 1000‐h aging. The diffusion of mirror coating from the resonant cavity surface is identified as a key factor contributing to high‐power LD degradation, which has not been reported in milliwatt‐level LDs. Meanwhile, the mechanisms behind the LD degradation are profiled and summarized together with the diffusion and other factors. On basis of the mechanism exploration, an anti‐aging technology for high‐power GaN‐based LDs is developed by using aluminum nitride for passivation layer and sapphire materials for mirror film. This anti‐aging technology has been verified, and a nearly ten‐time degradation suppression is achieved from 1000 h. This study elucidates the degradation mechanisms of high‐power GaN LDs and provides an effective technology to extend their lifespan, thereby prompting the practical applications of high‐power LDs.