Ultraviolet Photodetector Based on Mg_0.67Ni_0.33O Thin Film on SrTiO₃

Abstract

Herein, a new heterostructured ultraviolet metal–semiconductor–metal photodetector based on Mg 0.67 Ni 0.33 O thin film and SrTiO 3 is reported. The metal–semiconductor–metal photodetector comprises a 22 nm epilayer of Mg 0.67 Ni 0.33 O grown on SrTiO 3 (111) substrate by molecular beam epitaxy. A comparison of responsivities of the Mg 0.67 Ni 0.33 O–SrTiO 3 photodetector and reference SrTiO 3 photodetector shows that the heterostructured detector has close to an order of magnitude enhanced responsivity in the deep‐ultraviolet region. The responsivity of the Mg 0.67 Ni 0.33 –SrTiO 3 ‐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 Mg 0.67 Ni 0.33 O–SrTiO 3 photodetector are 10.7 and 8.6 ms, respectively, with the rise time more than two orders of magnitude shorter than the reference SrTiO 3 photodetector.