Zinc Cadmium Sulphide (Zn0.15Cd0.85S) thin-films by rf sputtering in an Ar-H2 atmosphere

Films of the title compound were prepared by radio-frequency sputtering from a (Zn,Cd)S target in pure Ar and Ar-H atoms. At a substrate temperature of 200°, Zn0.15Cd0.85S films grown in an Ar-H atmosphere exhibit a resistivity of ≈3 orders of magnitude lower than that of films grown in pure Ar. This is attributed to the formation of S vacancies by H reaction with a small number of the S atoms during the film deposition. The film grown in the Ar-H atmosphere exhibits a transparency of almost 100% when corrected for reflection loss for wavelengths longer than that of the absorption edge; the forbidden gap obtained from the absorption spectrum is ≈ 2.53 eV. The films prepared by sputtering in an Ar-H atmosphere are suitable for windows in CuInSe2/(Zn,Cd)S solar cells.