NOVELTY - Photovoltaic cell structure (20) comprises: (a) a substrate (21) having a rough surface; (b) a metal layer (22) formed on the rough surface of the substrate; (c) a p-type semiconductor layer (23) formed on the metal layer; (d) an n-type semiconductor layer (24) formed on the p-type semiconductor layer, thus forming a rough p-n junction; and (e) a transparent conductive layer (26) formed on the n-type semiconductor layer.    USE - The photovoltaic cell structure is useful for developing solar cells.    ADVANTAGE - The photovoltaic cell structure has increased photocurrent density and higher efficiency of power generation. It uses a rough substrate for effectively increasing the area of the p-n junction of the n-type semiconductor layer and the p-type semiconductor layer of the photovoltaic cell structure.    DETAILED DESCRIPTION - A photovoltaic cell structure (20) comprises: (a) a substrate (21) having a rough surface; (b) a metal layer (22) formed on the rough surface of the substrate; (c) a p-type semiconductor layer (23) formed on the metal layer and comprising copper indium gallium selenium sulfur, copper indium gallium selenium, copper indium sulfur, copper indium selenium or comprising a compound of at least two of copper, selenium, or sulfur; (d) an n-type semiconductor layer (24) formed on the p-type semiconductor layer, thus forming a rough p-n junction; and (e) a transparent conductive layer (26) formed on the n-type semiconductor layer. An INDEPENDENT CLAIM is included for a manufacturing the photovoltaic cell structure comprising: (a) providing a substrate; (b) roughing the substrate to form a rough surface on the substrate; (c) forming a metal layer on the rough surface; (d) forming a p-type semiconductor layer on the metal layer, where the p-type semiconductor layer comprises copper indium gallium selenium sulfur, copper indium gallium selenium, copper indium sulfur, copper indium selenium or comprises a compound of at least two of copper, selenium, or sulfur; (e) forming an n-type semiconductor layer on the p-type semiconductor layer, thus forming a rough p-n junction between the n-type semiconductor layer and the p-type semiconductor layer; and (f) forming a transparent conductive layer on the n-type semiconductor layer.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the photovoltaic cell structure.    Substrate (21)    Metal layer (22)    P-type semiconductor layer (23)    N-type semiconductor layer (24)    Transparent conductive layer (26)