Effect of thermal treatment on synthesized Cu doped ZnS nanoparticles

Abstract

Abstract Zinc sulphide (ZnS) nanoparticles are well known as one of the important inorganic semiconductors. Bandgap, shape, size and synthesis processes are the important parameters which decide the properties of NPs. Therefore the properties of nanoparticles (NPs) can be modified for a specific application by engineering it bandgap and size. In this paper ZnS and Cu doped ZnS (Cu-ZnS) nanoparticles were synthesized by chemical co-precipitation method. The Effect of thermal treatment on Cu-ZnS nanoparticles have been investigated via various characterization techniques. XRD studies confirm the formation of ZnS and Cu-ZnS NPs. Desulphurization of synthesized Cu-ZnS NPs has been observed at temperature 450 °C and above. From UV–Vis spectra, we observed the absorption wavelength of as synthesized ZnS and Cu-ZnS NPs around 215 nm and 218 nm respectively. Red shift in the bandgap of Cu-ZnS NPs has been observed due to annealing. There is a lack of reports on the effect of annealing temperature on magnetism in transition metal doped ZnS nanoparticles. Therefore Magnetic behaviour of synthesized sample has been studied via Vibrating Sample Magnetometer measurement. We have observed that the Cu-ZnS NPs exhibit ferromagnetism. We have reported the increased saturation magnetization at 450 °C. Maximum coercivity of 270 Oe has been observed for Cu-ZnS samples annealed at 350 °C. Thus this paper highlights the effect of annealing temperature of optical, structural and magnetic properties of Cu doped ZnS nanoparticles.