Back-to-back asymmetric Schottky-type self-powered UV photodetector based on ternary alloy MgZnO

Abstract

A back-to-back asymmetric Schottky self-powered UV photodetector (PD) with fast speed was realized by a facile combination of ternary alloy MgZnO film and asymmetric Au electrodes. The high-crystalline-quality MgZnO films were synthesized by metal organic chemical vapor deposition. Due to the incorporation of Mg, the band gap of MgZnO film was confirmed to be 3.76 eV. In addition, owing to the large Schottky barrier difference between the active layer and the two asymmetric Au electrodes, the responsivity of the device could reach up to 2.22 mA W−1 at the optical wavelength of 330 nm without any power supply, and with a sharp cutoff at the wavelength of 343 nm. The device exhibits a very low dark current of 247 pA at −5 V. More interestingly, the decay time of our device is only around 92 µs, which is much quicker than any other previously reported UV PDs even with bias voltage applied. Our findings provide a promising approach to realize a high-performance self-powered UV PD.