(JP10135498-A)      A thin film solar cell comprises a thin film light absorbing layer of a Cu-III-VI2 chalcopyrite-structured multi-element compound semiconductor, in which the solar cell comprises: (i) a metallic back electrode layer; (ii) a first thin semiconductor film of a Cu(InGa)Se2 multi-element compound of chalcopyrite structure formed on the back electrode layer, having p-type conductivity, and serving as a thin film light absorbing layer; (iii) a second thin semiconductor film of a transparent conductive metal oxide formed over the thin film light absorbing layer, having a wide band-gap width and n-type conductivity, and serving as a window layer and an electrode; and (iv) a thin transparent semiconductor film with high resistance deposited between the first thin semiconductor film and the second thin semiconductor film, and serving as an interfacial layer.    USE -   Used for thin film heterojunction solar cell containing a light absorbing layer comprising a multi-element compound semiconductor of the Cu-III-VI2 chalcopyrite structure.    ADVANTAGE -   The cell has heightened open circuit voltage, and improved interfacial junction characteristics which provide a high conversion efficiency and enhanced suitability for practical use.    (US5981868-A)      A thin film solar cell comprises a thin film light absorbing layer of a Cu-III-VI2 chalcopyrite-structured multi-element compound semiconductor, in which the solar cell comprises: (i) a metallic back electrode layer; (ii) a first thin semiconductor film of a Cu(InGa)Se2 multi-element compound of chalcopyrite structure formed on the back electrode layer, having p-type conductivity, and serving as a thin film light absorbing layer; (iii) a second thin semiconductor film of a transparent conductive metal oxide formed over the thin film light absorbing layer, having a wide band-gap width and n-type conductivity, and serving as a window layer and an electrode; and (iv) a thin transparent semiconductor film with high resistance deposited between the first thin semiconductor film and the second thin semiconductor film, and serving as an interfacial layer.    USE -   Used for thin film heterojunction solar cell containing a light absorbing layer comprising a multi-element compound semiconductor of the Cu-III-VI2 chalcopyrite structure.    ADVANTAGE -   The cell has heightened open circuit voltage, and improved interfacial junction characteristics which provide a high conversion efficiency and enhanced suitability for practical use.