GaN metal-semiconductor-metal UV sensor with multi-layer graphene as Schottky electrodes

Abstract

We fabricated a GaN-based metal-semiconductor-metal (MSM)-type UV sensor using a multilayer graphene as transparent Schottky electrodes. The fabricated GaN MSM UV sensor showed a high photo-to-dark current contrast ratio of 3.9 x 10(5) and a UV-to-visible rejection ratio of 1.8 x 10(3) at 7 V. The as-fabricated GaN MSM UV sensor with graphene electrodes has a low bias dependence of maximum photoresponsivity and a noise-like response at a visible wavelength in the 500 nm region. These problems were successfully solved by treatment with a buffered oxide etcher (BOE), and the photoresponse characteristics of the fabricated GaN MSM UV sensor after the treatment were better than those before the treatment. (C) 2015 The Japan Society of Applied Physics