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

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(a)-Department of Sciences and Technology, University Center of Tamanrasset, Algeria

(b)-LEA, Department of Electronics, University of Batna 2, Batna 05000, Algeria  

(c)-Research Scientific and Technical Center on Physico-Chemical Analysis (CRAPC), Algeria

Received 27 October 2020,

Revised 3 December 2020,

Accepted 5 December 2020,

Available online 18 December 2020.


Cost-effective multispectral photodetectors (PDs) exhibiting a high UVVisibleNIR 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 UVVisible-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 UVVis-NIR 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 ION/IOFF ratio of 78 dB and an enhanced responsivity in UV, visible and NIR ranges. The proposed multispectral PD demonstrates a high ION/IOFF 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.

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