Fabrication and optical characterization of GaN micro-disk cavities undercut by laser-assisted photo-electrochemical etching. (1st April 2023)

• Record Type: Journal Article
• Authors: Tajiri, T.; Sosumi, S.; Shimoyoshi, K.; Uchida, K.
• Is Part Of: Japanese journal of applied physics. Volume 62:Number SC(2023)
• Publication Date: 2023-04-01
• Subjects: gallium nitride -- photo-electrochemical etching -- micro-disk cavity; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/acb65a
• Languages: English
• ISSNs: 0021-4922

Abstract

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.