▎ 摘　　要

The III-nitride semiconductor microdisk laser exhibits high quality factor and low excitation threshold with broad development potential in the field of nanophotonics such as nanoscale light-emitting devices and on-chip optical integration. So far, many works have been focused on process synthesis and nanostructural design of microdisk lasers. Nevertheless, there are still some limitations in the existing optical resonance mode which is an important internal influence factor for lasing characteristics. In this work, a new double-triangular whispering-gallery mode (D3-WGM) lasing from a hexagonal GaN microdisk with a high quality (Q) factor of 3049 and an excitation threshold of around 11.5 mu W has been experimentally demonstrated. In addition, the optical properties of hexagonal-WGM (6-WGM), triangular-WGM (3-WGM) and D3-WGM lasing from microdisk are explored by numerical calculation and Comsol simulation. These results confirm that the D3-WGM lasing has its own significant performance advantages, namely high Q factor and easy light emission. Based on this novel laser mode characteristic, microcavity lasers are expected to be further developed and applied in the field of nanophotonics. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.