Synthesis and Characterization of Pure CdS Nanoparticles for Optoelectronic Applications

Pure CdS nanoparticles were synthesized by using a simple aqueous precipitation method at room temperature. The CdS nanoparticles were then subjected to low temperature heat treatment at 200°C for 2 h. The prepared powder was characterized by various analytical techniques such as powder XRD, SEM, TEM, thermal and spectroscopic analyses. XRD study confirmed the high crystalline nature of prepared compounds and the presence of hexagonal and cubic phases of the CdS nanoparticles. The particle size of CdS nanoparticles were calculated by Scherrer's formula and it was found that the particles were in the range of 8 to 10 nm. SEM images confirmed the homogeneous distribution of the nanoparticles. Photoluminescence studies of CdS nanoparticles showed green emission with peak intensity maximum at 535 nm. Raman spectra of the as-prepared and heat treated samples were recorded using Laser-Raman technique. The bandgap of the CdS particles was calculated from the absorption edge of the UV-Vis spectrum and was found to be 2.48 eV. TEM analysis revealed that most of the crystallites were spherullitic in nature and their size was around 10 nm, which agreed well with the XRD result.