AlN air-bridge photonic crystal nanocavities demonstrating high quality factor

The authors report an achievement of high quality AlN ultraviolet photonic crystal nanocavities. Convex AlN air-bridge structures with embedded GaN quantum dots have been formed by utilizing photoelectrochemical etching of 6H-SiC substrates. Room-temperature microscopic photoluminescence measurements reveal the high quality of the nanocavities. For the lowest-order cavity mode of a 150-nm-period nanocavity with seven missing holes, the highest Q factor (>2400) ever reported in nitride-based photonic crystals has been obtained.