NOVELTY - The solar cell has a buffer layer (104) formed in a transparent substrate (100). A transparent conduction layer (102) is formed on the transparent substrate. A window layer (106) is made of semiconductor compound and formed in the transparent conduction layer. A light absorption layer (108) is installed in the window layer. A back contact electrode (110) is arranged on the light absorption layer. An element is included between the transparent conduction layer and the window layer. The element is made of material selected from zinc, tin, sulfur, oxygen and copper.    USE - Thin film solar cell.    ADVANTAGE - The solar cell has high efficiency. The solar cell improves optical transmittance rate. The buffer layer can reduce leakage current between the transparent conduction layer and the light absorption layer so as to improve quantum efficiency of the solar cell and increases open circuit voltage. The high quality buffer layer foil can be deposited according to desired thickness so as to improve growth rate of the buffer layer.    DETAILED DESCRIPTION - The buffer layer is made of zinc sulfide and zinc oxide. The window layer is made of sulfide cadmium. The light absorption layer is selected from a group consisting of zinc oxide, zinc sulfide, zinc selenide, Zinc telluride, cadmium oxide, cadmium sulfide, cadmium selenide, cadmium telluride, magnesium oxide, magnesium sulfide, magnesium selenide, magnesium telluride, mercury oxide, mercury sulfide, mercury selenide, mercury telluride, aluminum nitride, aluminum phosphide, aluminum arsenide, aluminum antimonide, gallium nitride, gallium phosphide, gallium arsenide, gallium antimonide, indium nitride, indium phosphide, indium arsenide, indium antimonide, titanium nitride, titanium phosphide, titanium arsenide and titanium antimonide. An INDEPENDENT CLAIM is also included for a method for manufacturing a thin film solar cell.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a thin film solar cell.    Transparent substrate (100)    Transparent conduction layer (102)    Buffer layer (104)    Window layer (106)    Light absorption layer (108)    Back contact electrode (110)