A full free spectral range tuning of p-i-n doped gallium nitride microdisk cavity

Abstract

Effective, permanent tuning of the whispering gallery modes (WGMs) of p-i-n doped GaN microdisk cavity with embedded InGaN quantum dots over one free spectral range is demonstrated by irradiating the microdisks with a ultraviolet laser (380 nm) in DI water. For incident laser powers between 150 and 960 nW, the tuning rate varies linearly. Etching of the top surface of the cavity is proposed as the driving force for the observed shift in WGMs and is supported by experiments. The tuning for GaN/InGaN microdisk cavities is an important step for deterministically realizing nanophotonic devices for studying cavity quantum electrodynamics.