Nanostructured FeS2 films: Influence of effective parameters on electrochemical deposition and characterization of physical properties

Abstract

In this study, films of iron disulfide (FeS2) nanostructures are prepared by electrochemical deposition on the Fluorine-doped tin oxide (FTO) glass substrate. The effect of deposition parameters such as voltage, time, molarity, and also sulfurization temperature are studied as parameters affecting the physical properties of the deposited films. The prepared films are studied and characterized by analysis of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, photoluminescence (PL), and UV–Vis–NIR spectroscopy. Following sulfurization, the XRD analysis shows the cubic phase of pyrite. The phase purity of the prepared samples are confirmed by Raman spectroscopy and the presence of Fe and S elements is verified by EDX analysis. The micrograph of FESEM shows that different morphologies in porous, spherical, and flower-like forms in nanometer dimensions are obtained by changing the effective parameters. The PL spectrum shows the presence of emission bands in the visible region. With the increase in the sulfurization temperature, the light absorption intensity of the films increases and the energy band gap increases from 1.53 to 1.73 eV, confirmed by UV–Vis–NIR spectroscopic analysis. The Mott-Schottky's analysis shows the p-type conductivity. Based on the results, the amount of photosensitivity, photoresponsivity, and specific detectivity increases with the rise in temperature. The sample sulfurized at 250 °C, compared to the sample sulfurized at 200 °C, shows a remarkable photoresponsivity in the range of visible spectrum. The values of photoresponsivity, photosensitivity, and specific detectivity at 100 mW/cm2 intensity are 22.7 mA/W, 18.80%, and 0.37×109 (Jones), respectively. According to the obtained results, this material has the potential for use in the fabrication of high-efficiency optoelectronic devices.