SEM analysis and selenization of Cu–In alloy films produced by co-sputtering of metals

Co-sputtered copper–indium (Cu–In) alloy layers were investigated as precursors for CuInSe2 (CIS) formation. Results of scanning electron microscopy (SEM), EDS and X-ray diffraction (XRD) studies reveal the inhomogeneity of the films composition. The films have a rough surface structure with well-defined islands crystallized within the film matrix. The elemental composition of the island-type crystals corresponds to the compound CuIn2 and the composition of the matrix area corresponds to the Cu11In9 phase. The influence of heating temperature, time and Se pressure on the morphology and composition of films is studied using SEM, XRD and Raman spectroscopies. Thereby optimal technological parameters for the production of single-phase CIS layers are determined.