Optimization of Violet Emitting Quantum Wells with Insertion of AlGaN Layers and Temperature Ramp-up

Abstract

High-power InGaN-based violet laser diodes (LDs) have received great attention for their applications such as long-haul illuminations and material processing. 1 In order to achieve robust high-power devices, maintaining a high-quality multiple quantum well (MQW) active region is needed but challenging, since the laser structure requires a higher temperature growth for p-type (Al)GaN cladding layer. Some degree of degradation has been observed for InGaN/GaN quantum wells (QWs) after such high temperature growth. A concept of using an AlGaN cap layer to improve the thermal stability of InGaN/GaN MQWs has been developed and utilized in red-blue wavelength regime. 2 – 4 Besides the thermal stability, the insertion of the AlGaN cap also increases the quantum barrier height, reduces electron leakage, prevents indium out-diffusion from the QW. In this work, we extend such studies to the violet-emission regime for potential high-power laser applications.