Growth Mechanism and Optical Properties Determination of CdS Nanostructures

CdS nanocrystalline materials have been prepared by reaction of Cd(II) ions with an alkaline solution of thiocarbamide in the aqueous solution phase. The effect of reaction time and surfactants (cetyltrimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS)) on morphology and size of the products has been investigated. Dramatic shape and size variations have been observed by varying the surfactant and reaction time. CdS nanocrystals formed in various reactions were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) to determine the crystallinity, phase, composition, size, and morphology. The optical properties of the thus prepared samples were determined by UV–vis absorption spectra. A possible formation mechanism of CdS nanocrystals has also been discussed in this article.