High quality AlGaN solar-blind Schottky photodiodes fabricated on AIN/sapphire template

The authors report the high-performance AlGaN solar-blind Schottky photodiodes grown on AIN/sapphire templates by metal organic chemical vapor deposition. The devices exhibit dark current densities as low as 1.6×10−11A∕cm2 at −5V bias. The peak responsivity is 41mA∕W at 256nm in the photovoltaic mode, corresponding to a quantum efficiency of 20%. A sharp spectral response cutoff of more than two orders of magnitude by 300nm is observed under a low illumination intensity of 10nW∕cm2. The zero-bias resistance-area product of the device is found to be 5.0×1012Ωcm2, leading to an estimated detectivity of 7.0×1014cmHz1∕2∕W at 256nm.