Ultrasensitive Self-powered large area planar GaN UV-photodetector using reduced graphene oxide electrodes

摘要

A simplistic design of a self-powered UV-photodetector device based on hybridr-GO/GaN is demonstrated. Under zero bias, the fabricated hybrid photodetectorshows a photosensivity of ~ 85% while ohmic contact GaN photodetector withidentical device structure exhibits only ~ 5.3% photosensivity at 350 nmillumination (18 microWatt/cm^2). The responsivity and detectivity of thehybrid device were found to be 1.54 mA/W and 1.45x10^10 Jones (cm Hz^(1/2)W^(-1)), respectively at zero bias under 350 nm illumination (18microWatt/cm^2) with fast response (60 ms), recovery time (267 ms) andexcellent repeatability. Power density-dependent responsivity & detectivityrevealed ultrasensitive behaviour under low light conditions. The source ofobserved self-powered effect in hybrid photodetector is attributed to thedepletion region formed at the r-GO and GaN quasi-ohmic interface.