Preparation and characterization of Cu(In,Ga)(Se,S)2 films without selenization by co-sputtering from Cu(In,Ga)Se2 quaternary and In2S3 targets

▶ We report a chalcopyrite CIGS films prepared by co-sputtering a quaternary alloy target and an In2S3 binary target with a one-stage annealing process without post-selenization. ▶ Experimental results showed that the stoichiometry ratios of the CIGSS film were Cu/(In+Ga) = 0.92, Ga/(In+Ga) = 0.26, and Se/(S) = 0.49 that approached device-quality stoichiometry ratio (Cu/(In+Ga) < 0.95, Ga/(In+Ga) < 0.3, and (Se/S) ≈ 0.5). ▶ The resistivity of the sample was 14.8 Ω cm, with a carrier concentration of 3.4 × 1017 cm−3 and mobility of 1.2 cm2V−1 s−1. ▶ The resulting film exhibited p-type conductivity with a double graded band-gap structure.