Ultraviolet (UV) photodetectors (PDs) have useful applications including flame detection, environmental monitoring, early missile threat warning systems, etc. UV PDs based on wide-band-gap materials, such as GaN and ZnO have a visible-blind advantage over silicon-based PDs. ZnO is a potential absorber material with low-cost processing and simple synthesis, making it an alternative to GaN or SiC. It has thus attracted significant research interest. In this study, we report a high-performance visible-blind UV PD with a poly-(N-vinylcarbazole) (PVK) interfacial layer between NiO thin film and ZnO nanorods (NRs).The UV PD employs a low-cost sol-gel-derived NiO thin film as the p-type material, a thin PVK layer as the interface modification layer which can significantly reduce defect states at the NiO/ZnO interface and can minimize the leakage current, and low-temperature chemical bath synthesized ZnO NRs as the UV light-detecting material. Several features are demonstrated in this study: (a) the insertion of a PVK interlayer can effectively suppress the leakage current and can reduce carriers recombination at the interface, thus giving rise to a larger amplification of the photocurrent; (b) with a PVK interlayer, the UV PD exhibits a high UV-to-visible rejection ratio, which can achieve a higher signal-to-noise ratio; (c) the PD with high photoconductive gain can be attributed to the adsorption of oxygen molecules on the surface of ZnO NRs. The proposed PD has the potential for developing low-cost and high-performance UV PDs in sensing applications.
Journal: TechConnect Briefs
Volume: 4, Informatics, Electronics and Microsystems: TechConnect Briefs 2018
Published: May 13, 2018
Pages: 213 - 216
Industry sector: Sensors, MEMS, Electronics
Topic: Photonic Materials & Devices