Cadmium suphide films prepared by pulsed electrodeposition

• Published in: Solar energy materials and solar cells Vol. 27; no. 4; pp. 305 - 319
• Main Authors: Morris, G.C., Vanderveen, R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1992
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/0927-0248(92)90092-4

Cadmium sulphide polycrystalline films were deposited on glass/indium tin oxide by periodic pulse electrolysis from aqueous solutions of cadmium chloride and sodium thiosulphate at 90°C. The properties of the films were determined as functions of the deposition variables, viz. cathodic voltage, V c , anodic voltage, V a , cathodic on time, t c , deposition temperature, and solution concentrations of Cd 2+ and S 2O 3 2−. Film quality was judged by adherence, continuity, transmittance, as well as compositional and morphological properties. The range over which the voltages (versus SCE) could be altered was limited to −1.1 V < V c < −0.8 V, V a < 0.65 V . The preferred deposition conditions were V a = +0.6 V, V c = −0.95 V, t a = 2 s, and t c = 1 s , with a solution whoese composition was 0.2 M Cd 2+, 0.01 M S 2O 3 2, and pH = 2 at a temperature of 90°C. Films deposited under those conditions were hexagonal polycrystals with grain size about 56 nm which were strongly adherent to the ITO, and had excellent surface coverage and high optical transmittance. The through plane resistivity of the films was 2.5 × 10 4 Ω cm (dark) and 700 Ω cm (100mW cm −2, AM1 irradiation). The band gaps of the films were 2.53 ± 0.04 eV (as deposited) and 2 ± eV (annealed).