Optoelectronic Studies of Commercially and Lab Prepared Cadmiumsulfide Chalcogenide

Cadmium Sulfide (CdS) chalcogenide has been prepared by coprecipitation method. Both cubic and hexagonal phases existed in the commercially obtained CdS (S1) whereas the lab prepared samples using ethanol (S2) and distilled water (S3) existed homogeneously in the cubic phase only. Average crystallite size as determined by Debye- Scherrer formula for samples S1, S2 and S3 are 20.9, 3.5 and 4.9 nm respectively. SEM images of all samples show that the surface morphologies are in the form of assemblies of nanoparticles. Absorption spectra show a peak at 538 nm for the sample S1, at 482 nm for S2 and at 516 nm for S3. Optical size as calculated by Brus equation for S1, S2, and S3 are 4.47, 4.00, and 10.96 nm respectively. Absorption coefficient of the sample decreases continuously from visible region to near ultraviolet region while absorption constant of the sample increases up to the visible region as wavelength increases. PL spectra indicate effective photoemission property in the visible region. FTIR spectra show a peak at 610 cm-1 for prepared samples S2 and S3 which is attributed to CdS formation.