Abstract: A method for producing a thin-film solar cell having a thin-film active layer on a graphite sheet substrate includes the steps of adhering two sheets of graphite together, forming semiconductor thin films serving as active layers on second main surfaces of the two sheets of graphite, and separating the two sheets of graphite from each other. In this structure, stress caused by a difference in expansion coefficients between the upper sheet and the semiconductor thin film is cancelled by stress caused by a difference in expansion coefficients between the lower sheet and the semiconductor thin film. Therefore, curvature of the substrates is prevented whereby subsequent process steps are easily carried out. In addition, the number of products per unit time is doubled, thereby increasing productivity.

Abstract: A thin-film solar cell includes a thin active layer of high purity material having opposed front and rear surfaces for light-to-electricity conversion, a structure for supporting the thin active layer, and a rear electrode in contact with the rear surface of the active layer. The supporting structure includes a supporting substrate of a low purity material having opposed front and rear surfaces, on the front surface of which the rear surface of the active layer is disposed, and an insulating barrier layer interposed between the front surface of the supporting substrate and the rear surface of the active layer. The barrier layer prevents impurities in the supporting substrate from diffusing into the active layer. Since the supporting substrate comprises a low purity material, the quantity of the expensive high purity material can be reduced by reducing the thickness of the active layer, resulting in low production costs.

Abstract: A method for producing a thin-film solar cell having a thin-film active layer on a graphite sheet substrate includes the steps of adhering two sheets of graphite together, forming semiconductor thin films serving as active layers on second main surfaces of the two sheets of graphite, and separating the two sheets of graphite from each other. In this structure, stress caused by a difference in expansion coefficients between the upper sheet and the semiconductor thin film is cancelled by stress caused by a difference in expansion coefficients between the lower sheet and the semiconductor thin film. Therefore, curvature of the substrates is prevented whereby subsequent process steps are easily carried out. In addition, the number of products per unit time is doubled, thereby increasing productivity.

Abstract: A solar cell includes a first conductivity type silicon substrate, a second conductivity type layer of microcrystalline or amorphous silicon deposited on the substrate in a plasma process and consuming an oxide film no more than 2 nanometers thick formed on the substrate before depositing the second conductivity type layer, a transparent electrode layer disposed on the second conductivity type layer, a grid electrode disposed on the transparent electrode layer, and an electrode disposed on the substrate.

Abstract: A method for producing a thin-film solar cell having a thin-film active layer on a graphite sheet substrate includes the steps of adhering two sheets of graphite together, forming semi-conductor thin films serving as active layers on second main surfaces of the two sheets of graphite, and separating the two sheets of graphite from each other. In this structure, stress caused by a difference in expansion coefficients between the upper sheet and the semiconductor thin film is cancelled by stress caused by a difference in expansion coefficients between the lower sheet and the semiconductor thin film. Therefore, curvature of the substrates is prevented whereby subsequent process steps are easily carried out. In addition, the number of products per unit time is doubled, thereby increasing productivity.

Abstract: A tank has an upper shell and a lower shell. The shells have flanges at their periphery which are seam-welded to form a tank. A plurality of projections formed on the flange of the upper shell and a plurality of recesses formed on the flange of the lower shell fit together thereby to prevent the flanges from displacing each other when they are seam-welded. Also, a method for making the tank is disclosed.