Comparison of Two Methods Fabricating CuInSe_2 Polycrystalline Films

The CuInSe 2(CIS) films were fabricated by selenization of evaporated metallic precursors and vacuum evaporation of stacked elemental layers(SEL) followed by a thermal annealing step.The morphology,microstructure and composition of the films were investigated by scanning electron microscopy(SEM),X-ray diffraction(XRD) and energy dispersive X-ray spectroscopy(EDX).The results show that these two thin films are both compact and uniform.The grain sizes of the two kinds of films are 1.5 μm and 1.0 μm,respectively.All the films made by the two methods are Cu-rich and show p-type conduction.However,the CIS thin films fabricated by the former method consist of a single phase of chalcopyrite structure,while those films fabricated by the later method contain impurity phases such as β-In 2Se 3 besides CIS phase.Thus the former method is better for fabricating the CIS absorber in solar cells.