Influence of Ge composition in the Cu2Sn1-xGexS3 thin-film photovoltaic absorber prepared by sulfurization of laminated metallic precursor

Cu2Sn1-xGexS3 thin-film absorbers are prepared by sulfurization of laminated precursors. The crystal grain size is enhanced under higher growth temperature and/or sulfur pressure. By the XRD and Raman analyses, the crystal alloy is considered to be composed of majority monoclinic phase with minority secondary phase such as Cu-2(Sn1-xGex)(3)S-7 throughout the whole Ge/(Ge+Sn) composition range. The optical band gap is observed to be varied between 0.94 eV and 1.30 eV in relation with the Ge contents. A photovoltaic conversion efficiency of about 2% is obtained in the sample utilizing Cu2Sn0.6Ge0.4S3 absorber. (C) 2015 Elsevier B.V. All rights reserved.ArticleSOLAR ENERGY MATERIALS AND SOLAR CELLS. 140:312-319 (2015)journal articl