Cu(In,Al)S 2 Thin Film Solar Cell

A Cu(In,Al)S 2 thin film solar cell has exhibited good adhesion to Mo-coated glass and comparatively high efficiency. The sputter-deposited metallic precursor was sulfurized and then treated in a KCN solution to remove a Cu x S impurity phase and an excessive Al compound from the film surface. When the precursor layer was Cu-rich, the treated sulfide film could be used as an efficient absorber material. It had the same band gap as CuInS 2 . The spectral response of the cell was increased in a short wavelength range. The bottom region of the film was considered to consist of a Cu(In,Al)S 2 alloy that enhanced the film adhesion to the Mo back contact. The film was analyzed using X-ray diffraction, electron probe microanalysis, scanning electron microscopy and field ion microscopy combined with focused ion beam technique.