III-Nitride ultraviolet laser

Abstract

A variety of studies focusing on the III-nitride deep-ultraviolet (DUV) edge-emitting laser and vertical cavity surface-emitting laser (VCSEL) based on metalorganic chemical vapor deposition (MOCVD) are elaborated. Transverse electric (TE)-dominant DUV edge-emitting lasing with a low threshold was demonstrated on the bulk AlN substrate. DUV surface superluminescence was achieved from the AlGaN heterostructure on the sapphire substrate. Furthermore, the temperature dependence study indicated that the high temperature growth did not necessarily lead to the AlN/sapphire template with better material quality. Based on that, the optimized recipe was developed to grow the high quality AlN/sapphire template without the use of high temperature, epitaxial lateral overgrowth (ELO), and pulse atomic layer epitaxy (PALE) methods. Thus the recipe is simple which can be transferred to most of the III-nitride MOCVDs. In addition, state-of-the-art optically-pumped edge-emitting DUV lasers with record-low thresholds and record-short wavelengths were demonstrated on the optimized AlN/sapphire templates. The first optical polarization switching of DUV lasing on any given substrate was observed. Moreover, the growth of single-phase wurtzite BAlN layers with high-B contents and large thicknesses were demonstrated for the distributed Bragg reflector (DBR) application. These works have notable significance in the pursuit of electrically-pumped DUV edge-emitting and surface-emitting laser diodes (LDs).