Self-powered photodetector with improved and broadband multispectral photoresponsivity based on ZnO-ZnS composite

Cost-effective multispectral photodetectors (PDs) exhibiting a high UV-Visible-NIR photoresponse offer an avenue for developing environmental monitoring devices, imaging sensors, object discrimination, and optical links. However, PDs based on a single semiconductor as light-sensitive layer are unable to provide broadband photodetection properties. In this work, a new PD device based on ZnO-ZnS Microstructured Composite (MC) which achieves a high UV-Visible-NIR photoresponse is demonstrated. The ZnO-ZnS MC is elaborated by combining vacuum thermal evaporation technique and a suitable annealing process. Scanning Electron Microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and UV-VisNIR spectroscopy were used to elucidate the morphological, structural and optical properties of the prepared sample. It was demonstrated that the ZnO-ZnS MC can be useful to enhance the visible absorbance efficiency by promoting efficient light-scattering effects. It is revealed that the prepared UV-Vis-NIR PD offers a low dark current of 5 nA, a high I-ON/I-OFF ratio of 78 dB and an enhanced responsivity in UV, visible and NIR ranges. The proposed multispectral PD demonstrates a high I-ON/I-OFF current ratio under self-powered working regime. Therefore, the proposed ZnO-ZnS MC is believed to provide new insights in developing efficient, self-powered and low-cost multispectral PDs for high-performance optoelectronic systems. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

A new multispectral photodetector based on ZnO-ZnS Microstructured Composite is demonstrated to achieve high UV-Visible-NIR photoresponse with efficient light-scattering effects for enhanced visible absorbance efficiency. The device shows low dark current, high I-ON/I-OFF ratio, and enhanced responsivity in UV, visible and NIR ranges, making it suitable for high-performance optoelectronic systems.