Chemo-phototronic effect induced electricity for enhanced self-powered photodetector system based on ZnO nanowires

Self-powered ultraviolet (UV) photodetectors based on ZnO nanowires have attracted considerable interest due to low-cost and ease of fabrication. Effective strategies to enhance their photoresponse still remain challenging. Here we report a 4 x 4 matrix of self-powered ZnO UV photodetector system with optimized ZnO nanowire photoelectrode/electrolyte heterostructures. Modulating pH-dependent chemo-phototronic effect can regulate optoelectric and chemoelectric processes, resulting in significantly improved photodetection performance. The maximum photocurrent and photoresponsivity up to 290.02 mu A and 4.74 x 10-2 A W-1 can be achieved by using NaOH aqueous electrolyte (pH 13), which have been enhanced by 2056% as compared with that of utilizing deionized water electrolyte (pH 7). The enhanced performance is related to the pH-dependent chemical reaction, Schottky-like barrier height and depletion region width modulation at ZnO/electrolyte interface. This work provides guidelines to fabricate high-performance self-powered photodetector system of using semiconductor/ electrolyte heterostructures, pushing forward the advancement of high-sensitivity and low-cost photodetector array system.

Automated summary

This study presents a self-powered ZnO UV photodetector system with optimized ZnO nanowire photoelectrode/electrolyte heterostructures, showing significantly improved photodetection performance by modulating pH-dependent chemo-phototronic effect. The enhancement in performance is related to pH-dependent chemical reaction, Schottky-like barrier height, and depletion region width modulation at the ZnO/electrolyte interface. The guidelines provided can lead to the fabrication of high-performance self-powered photodetector systems using semiconductor/electrolyte heterostructures, advancing the development of high-sensitivity and low-cost photodetector arrays.