Pyro-phototronic application in the Au/ZnO interface for the fabrication of a highly responsive ultrafast UV photodetector

Abstract

We report the fabrication of a highly responsive ultrafast UV photodetector which utilizes combined photovoltaic and photo-induced pyroelectric effect or pyro-phototronic effect. The device architecture has a layered configuration where the photoactive layer is composed of gold nanoparticles (Au NPs) and zinc oxide (ZnO). Inclusion of sputter-deposited Au NPs in the device geometry exploits the UV absorption in Au NPs through interband transition along with exciton generation in ZnO, resulting in enhanced photocurrent generation in the UV region (365 nm). Moreover, the inherent pyroelectric property of the synthesized c axis oriented ZnO helps in boosting the speed of the fabricated device. The maximum photoresponsivity and specific detectivity of the fabricated device are calculated to be 4.68 AW−1 and 8.18 × 1011 Jones respectively in biased condition, thus making it one of the best among its compeer UV photodetectors. Additionally, the device demonstrates an ultrafast response time of 15 μs in the self-powered condition, which is another feather in its cap. So, this study opens up a new pathway for the application of combined carrier generation by interband transition and pyro-phototronic effect for the fabrication of highly responsive ultrafast pyro-phototronic UV detector.