UC Berkeley

Transparent diodes formed by a heterojunction between p-type CuS–ZnS and n-type ZnO thin films were fabricated by sequential chemical bath deposition and sol-gel spin coating. The diodes are transparent in the visible (≈70% at 550 nm) and exhibit a good rectifying characteristics, with If/Ir ratios of up to 800 at ±1 V, higher than most of the reported solution-processed diodes measured at a similar bias. More importantly, when operated as a self-powered (zero bias) UV photodetector, they show stable and fast (<1 s) photoresponse with a maximum responsivity of 12 mA W−1 at 300 nm. Both the response time and responsivity of the p-CuZnS/n-ZnO UV photodiode are comparable or superior to similar solution-processed devices reported in the literature.