A high performance self-powered ultraviolet photodetector based on a p-GaN/n-ZnMgO heterojunction

A high performance p-GaN/n-ZnMgO heterojunction photodiode was demonstrated and investigated. A high quality p-GaN film was grown on GaN/sapphire templates by plasma-assisted molecular beam epitaxy and subsequently an n-ZnMgO layer was deposited on p-GaN by a metal organic chemical vapor deposition technique. The p-GaN/n-ZnMgO heterojunction photodetector shows a clear rectifying I-V characteristic with a turn-on voltage of 2.5 V. At zero-bias voltage, the device shows a high peak responsivity of 196 mA W-1 at 362 nm. The 10-90% rise time and 90-10% decay time of the device can be as short as 1.7 ms and 3.3 ms, respectively. The excellent crystal quality and electrical properties of p-GaN play an important role in the high performance of the photodiode. This work provides a feasible way for the development of high-performance heterojunction self-powered UV detectors.