Effect of annealing temperature on the structural, optical, and electrical properties of MoS2 electrodeposited onto stainless steel mesh

Abstract

Molybdenum disulphide (MoS2) thin films were deposited on flexible stainless steel mesh (SSM) using an electrodeposition method. The influence of annealing treatment from 200 to 800 °C under a Nitrogen atmosphere for 30 min, on the structural, morphological, optical, and electrical properties of samples were investigated. X-ray diffraction showed that MoS2 thin film annealed at 700 °C exhibited the best crystalline quality with (002) preferential orientation. Scanning electron microscopy showed that the films were compact and grain size increased with increasing annealing temperature, from 825 nm to 1.5 µm, whereas annealing at a higher temperature (800 °C) resulted in a significant agglomeration of MoS2. According to the UV–Vis diffuse reflectivity spectra, the band gap of thin films was deduced in the range between 1.52 and 1.56 eV. Through photoluminescence measurement, it was demonstrated that among the five samples annealed at different temperatures, the 700 °C-annealed sample presents the lowest intensity with a narrow shape. Using the electrochemical impedance spectroscopy data, the interface was modeled as an equivalent circuit approach. From Mott–Schottky plots, the flat-band potential and the acceptor density for MoS2 thin films are determined. All the films showed an n-type semiconductor character with the highest carrier density of 4.8 × 1022 cm−3 and lowest flat-band potential of −0.55 V when the annealing was maintained at 700 °C. These results suggest that the MoS2 thin film electrodeposited on SSM substrate and annealed at 700 °C under N2 atmosphere is a promising strategy in the range of chalcogenide material suitable for the photoelectrochemical applications.