High-Q AlN photonic crystal nanobeam cavities fabricated by layer transfer

High-quality-factor one-dimensional photonic crystal nanobeam cavities embedding GaN/AlN quantum dots are fabricated by an epilayer transfer method. The GaN/AlN quantum dots are first grown on SiC before being transferred to a Si substrate using a hydrogen silsesquioxane bonding layer and highly selective back-etching of the SiC. Nanobeam cavities are then fabricated by electron-beam lithography, dry etching, and HF underetching of the bonding layer. The resulting nanocavity exhibits quality factors larger than 6.3 × 103, the highest quality factor reported to date for an optically active group-III nitride photonic crystal nanocavity.