Chemical and structural characterization of physical‐vapor deposited CuInSe2 for solar cell applications

This paper reports the results of a comparative study of chalcopyrite‐structure CuInSe2 deposited by three techniques, three‐source evaporation, reactive sputtering and a hybrid sputtering, and evaporation method. All films exhibit comparable microstructures and microchemistries. Evaporated and hybrid‐process films include significant porosity. All layers show dislocations, twins, and stacking faults. No second phases were observed in layers deposited by any of the techniques, independent of film composition. Data supporting this conclusion include average and single‐grain energy‐dispersive x‐ray fluorescence spectroscopy measurements, diffraction studies of the film structure, and transmission electron microscopy images of the films. Finally, grain sizes can be increased by annealing films at temperatures above 400 °C.