Synthesis and characterization of CZTGSe and CZTGSSe powders by ball milling technique: influence of Ge content and the role of Cu on the properties of CZTSe

CZTSe, CZTGSe and CZTGSSe powders were synthesized by the ball-milling technique, using elemental Cu, Zn, Sn, Ge, S and Se as the materials source. Kesterite synthesis route employs a one-step approach consisting of a direct precursor crystallization step. Morphological, structural and compositional ratios analyses are presented for different Ge-doping, using Scanning Electron Microscopy (SEM), x-ray Diffraction (XRD) and XRF. The influence of the inclusion of Ge in the above properties, as well as the role of Cu content in the formation of undesirable secondary phases in CZTSe powders are analyzed in terms of the use of this technique in the processing of high efficiency solar cells based on Kesterite compounds.