Ultraviolet Photodetector Based on Mg0.67Ni0.33O Thin Film on SrTiO3

Abstract

Herein, a new heterostructured ultraviolet metal-semiconductor-metal photodetector based on Mg0.67Ni0.33O thin film and SrTiO3 is reported. The metal-semiconductor-metal photodetector comprises a 22 nm epilayer of Mg0.67Ni0.33O grown on SrTiO3 (111) substrate by molecular beam epitaxy. A comparison of responsivities of the Mg0.67Ni0.33O-SrTiO3 photodetector and reference SrTiO3 photodetector shows that the heterostructured detector has close to an order of magnitude enhanced responsivity in the deep-ultraviolet region. The responsivity of the Mg0.67Ni0.33-SrTiO3-based photodetector at 320 nm is 415 mA W-1, with dark current lower than 40 pA at a bias of 10 V. The rise and fall times of Mg0.67Ni0.33O-SrTiO3 photodetector are 10.7 and 8.6 ms, respectively, with the rise time more than two orders of magnitude shorter than the reference SrTiO3 photodetector.