High efficiency NiO/ZnO heterojunction UV photodiode by sol-gel processing

We studied the thin film heterojunction photodiode made of nickel oxide (NiO) and zinc oxide (ZnO) deposited by low cost energy-efficient sol-gel spin coating. The highly visible-transparent heterojunction photodiode with a smooth interface gives rise to a good photoresponse and quantum efficiency under ultra-violet (UV) light illumination. With an applied reverse bias of 5 V, a very impressive peak photo responsivity of 21.8 A W-1 and an external quantum efficiency (EQE) of 88% at an incident light wavelength of 310 nm were accomplished.