Realization of a self-powered ZnO MSM UV photodetector with high responsivity using an asymmetric pair of Au electrodes

Abstract

We demonstrate a novel type of ZnO self-powered photodetector based on the asymmetric metalsemiconductor-metal (MSM) structure: one Au interdigitated electrode with wide fingers and the other one with narrow fingers. These ZnO photodetectors exhibit attractive photovoltaic characteristics at 0 V bias. More interestingly, with increasing the asymmetric ratio (the width of wide fingers : the width of narrow fingers) of the interdigitated electrodes, the responsivity of the ZnO self-powered UV photodetectors was enhanced obviously, reaching as high as 20 mA W À1 when the asymmetric ratio was 20 : 1. A physical model based on band energy theory was developed to illustrate the origin of the photoresponse at 0 V in our device. Our findings provide a new route to realizing self-powered photodetectors.

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“…6 demonstrates the structure of the realized rGO/ZnO photodetector (part (a)) and the operation mechanism of the device (part (b)), when exposed to illumination. It is known that surface processes in optoelectronic devices based on ZnO nanostructures play a crucial role because of large surface-to-volume ratios [46][47][48][49][50]. It can be observed in Fig.…”

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