Synthesis of nanostructured Cd-Se-Te films through periodic voltammetry for photoelectrochemical applications

In the present investigation, polycrystalline semiconductor Cd-Se-Te films have been electrodeposited at room temperature on conducting glass substrates using cyclic voltammetric technique under controlled periodic scans. The successive anodic and cathodic scans were recorded within the potential range, from 0 to -1.0 V, and over the range of periodic cycles, from 250 to 2,000, in an acidic bath containing respective reducible precursor ions like Cd2+, Se4+, Te4+, and 1 vol.% Triton X-100 as the surface-active reagent. Thin composite films were produced having variable thickness and composition and grain size of the order of 80-100 nm. The film properties were determined by focused ion beam analysis, energy dispersive analysis of x-rays, x-ray diffraction studies, atomic force microscopy, and scanning electron microscopy. Thickness of the semiconductor films was found to increase linearly with the number of voltammetric cycles. Band gap energies of the films as derived from the reflectance spectra were found to lie between 1.4 and 1.7 eV. The composite films of the Cd-Se-Te ternary system when electrochemically characterized in aqueous polysulfide solution exhibited n-type semiconducting properties and photoconversion efficiency more than 0.4%.