Comparison of thin film properties and selenization behavior of CuGaIn precursors prepared by co-evaporation and co-sputtering

CuGaIn precursors prepared by co-evaporation and co-sputtering processes were compared. The morphologies, degree of incorporation of Ga into CIGS, and the MoSe2 layer thicknesses of Cu(InGa)Se2 thin films fabricated by the rapid thermal annealing of metal precursors deposited by the two different processes differed owing to the precursor feature differences. Furthermore, a comparison of the isothermal in situ high-temperature X-ray scans of both precursors at 300 °C revealed that the selenization rate of the co-evaporated CuGaIn precursor is much higher than that of the co-sputtered precursor, which might be due to the lower film density of co-evaporated precursor. It is suggested that co-evaporated precursor should be a promising alternative for sputtered precursor to overcome the long process time and low throughput issue of 2-step sputter–selenization process, and simultaneously improve Ga incorporation and surface smoothness.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The density of co-evaporated CuGaIn film is lower than that of co-sputtered one. ► Lower density CuGaIn precursors lead to the better incorporation of Ga. ► The selenization of co-evaporated CuGaIn is faster than that of co-sputtered one. ► Co-evaporated CuGaIn precursor is a promising alternative for sputtered precursor.