Preparation by a facile method and characterization of amorphous and crystalline nickel sulfide nanophases

A simple solvothermal route using a domestic microwave oven has been developed to prepare the prominent nickel sulfide nanophases (amorphous NiS, and crystalline NiS1.03, β-NiS and α-NiS). The prepared nanophases have been characterized chemically, structurally, optically, electrically, and magnetically by the available methods like thermogravimetric and differential thermal analyses, X-ray powder diffraction analysis, scanning electron microscopic, and transmission electron microscopic analyses, energy dispersive X-ray spectroscopic, Fourier transform-infrared spectral, UV-Vis spectral and photoluminescence spectral analyses, AC and DC electrical measurements at various temperatures in the range 40-150 °C, and vibrating sample magnetometric measurements. The average particle sizes obtained through transmission electron microscopic analysis are 15, 17, 18, 20 nm respectively for the amorphous NiS, NiS1.03, β-NiS and α-NiS nanophases. Results obtained in the present study indicates that the method adopted is found to be an effective and economical one for preparing these nanophases with high purity, reduced size, homogeneity, and useful optical, electrical and magnetic properties.