Cd(S(1 − x) + CO3(x)) thin films by chemical synthesis

Abstract

A microcrystalline mixture of cadmium carbonate (CdCO3) and cadmium sulfide (CdS) were grown in the thin film format onto glass substrates by means of chemical bath. The temperature of the bath (T d ) was selected in the interval 23–80∘C. At low temperatures, CdCO3 is the compound predominant in the layers. At high temperatures CdS is the compound deposited on the substrate. At intermediate T d -values a mixture of both materials are present, i.e., the gradual transition from an insulator (CdCO3) to a semiconductor (CdS) growth occurs when T d increases. Physical properties of films were studied by means of X-ray diffraction and optical absorption. The forbidden energy band gap of direct electronic transitions (E g ) was calculated by applying the α2 ∝ (hν − E g ) relation to the optical absorption spectra.