Multispectral self-powered below room-temperature ZnS photodetector

Abstract

Self-powered devices are being seen as the next generation of disruptive technologies for majority of the internet-of-thing (IoT) devices. We report on a self-powered UV–visible photodetector engineered using zinc sulphide (ZnS) thin films grown over, in-house spray-coated fluorine-doped tin-oxide (F: SnO2) thin films. The growth of the active material was carried out at a temperature of 20 °C using sequential ionic layer adsorption reaction (SILAR) method. The effect of vacuum-annealing at 200 °C on the structural, morphological, optical, compositional and optoelectronic parameters of the ZnS thin films was investigated using XRD, TEM, FESEM, optical absorption, photoluminescence, XPS and photoconductivity studies. The novel facets of this work include multispectral response and high photosensitivity of the Schottky contact (F: SnO2/ZnS/Ag) achieved from the ZnS active material grown below room-temperature conditions. The responsivity and detectivity for the optimized self-driven photodetector in our present study are 240 × 10−4 AW−1 and 15.10 × 1010 Jones, respectively. The optimized detector under white-light illumination exhibited an excellent ON/OFF ratio of ~ 331. Graphical Abstract: [Figure not available: see fulltext.].