High-Q (>5000) AlN nanobeam photonic crystal cavity embedding GaN quantum dots

We report on the fabrication and optical characterization of high-quality-factor AlN one-dimensional nanobeam photonic crystal cavities embedding GaN quantum dots and operating in the ultra-violet range. By means of electron-beam lithography, dry etching and photoelectrochemical etching, we implement a high-frequency nanobeam cavity design in an AlN epilayer containing GaN quantum dots. Room-temperature microphotoluminescence characterization of the fabricated nanobeams exhibits resonances with wavelengths as short as 320 nm and quality factors as high as Qexp = 5.0 × 103 at 380 nm. This constitutes a significant improvement over previously reported group-III nitride photonic crystal cavities in terms of operating wavelength.