Highly sensitive and self-powered ultraviolet photodetector based on GaN/poly(styrenesulfonate)/polyaniline hybrid heterojunction

Abstract

A series of highly sensitive and self-powered ultraviolet (UV) photodetectors were prepared. The photodetectors adopt a p-i-n heterojunction structure composed of a layer of molecular beam epitaxy (MBE) grown n-type GaN, a layer of spin coated high resistance poly (styrenesulfonate) (PSS) and a layer of dip-coating applied p-type polyaniline (PANI) synthesized by oxidation reaction. The effects of the thickness of PSS and PANI on device performance were investigated. With the increase of PANI and PSS thickness, the photocurrent increases and reaches the highest value, and then decreases gradually with the further increase of their thickness. The optimized device can rapidly produce a photocurrent of 2.05 μA when illuminated with a 6.7 mW/cm2 UV light at 365 nm without any external power supply. This type of UV photodetector has potential applications in optoelectronics.