Single ZnO Microrod Ultraviolet Photodetector with High Photocurrent Gain

Abstract

An Ag/ZnO microrod/Ag ultraviolet photodetector is fabricated, the ZnO microrod shows a hexagonal whispering gallery cavity structure. Upon a 325 nm ultraviolet illumination, the device shows a high sensitivity of 4 × 10(4) A/W and a high photocurrent gain of 1.5 × 10(5) at 5 V bias. Under different illumination power P, the photocurrent Ilight obeys a power law relation Ilight ∝ P(0.69). The high performance is probably attributed to a Schottky barrier at Ag/ZnO interface and optical whispering gallery mode effect in the ZnO microrod.