Visible-blind deep-ultraviolet Schottky photodetector with a photocurrent gain based on individual Zn_2GeO_4 nanowire

摘要

We report on the visible-blind deep-ultraviolet (DUV) photodetectors with metal-semiconductor-metal (MSM) Schottky contacts based on individual Zn_2GeO_4 nanowire single-crystals. At an 8 V bias voltage, the device shows an extremely low dark current (<0.1 pA), a responsivity of 38.3 AAV (corresponding gain ～200), a high DUV-to-visible discrimination ratio up to ～10~4, and a relatively fast response time upon 245 nm DUV illumination. By analyzing the light-intensity-dependent photocurrent generation and carrier transport, the photogenerated holes trapped in Schottky barrier and shrinking of depletion region under DUV illumination at the metal/Zn_2GeO_4 interface are proposed for the carrier injection and the photocurrent gain.