抄録
Abstract
GaN micro-disk cavities undercut by laser-assisted photo-electrochemical (PEC) etching are fabricated and optically characterized. The laser source used in the PEC etching is tuned to be absorbed by the InGaN/GaN superlattice beneath the GaN disk to selectively etch the superlattice. Whispering gallery modes (WGMs) in fabricated GaN micro-disk cavities are evaluated by micro-photoluminescence spectroscopy of light emission from the embedded InGaN quantum wells. Quality factors estimated for the WGMs reach approximately 6700 at blue-violet wavelengths. Detailed analysis suggests that the high-Q WGMs are the fundamental WGMs. These results indicate the high applicability of laser-assisted PEC etching to the fabrication of air-clad GaN micro-cavities.