AlGaN/GaN Schottky-barrier UV-B bandpass photodetectors with ITO contacts and LT-GaN cap layers

Al0.2Ga0.8N/GaN Schottky-barrier ultraviolet (UV)-B bandpass photodetectors (PDs) with indium–tin–oxide (ITO) contact on low-temperature (LT)-GaN cap layers were fabricated and characterized. It was found that dark currents of our PDs were low due to the highly resistive LT GaN cap layers. It was also found that we can realize UV-B PDs with different bandwidths by controlling thickness and annealing conditions. The detectivity, D ∗ , of the PDs with ITO contacts was also larger than the conventional PDs with Ni/Au contacts.