TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The nitrate ion is supplied from a compound selected from indium nitrate, magnesium nitrate, aluminum nitrate, sodium nitrate or potassium nitrate. The indium ion is supplied from a compound selected from indium nitrate, indium chloride, indium sulfate or indium hydroxide. (A1) includes a solution obtained by dissolving an indium material (preferably indium metal or an indium alloy) in nitric acid. (A1) is maintained at 20 - 60 degreesC upon the film formation. The counter electrode is insoluble in (A1). (1) is shaped in a sheet, plate or roll form.Preferred Components: (1) comprises a combination comprising a substrate and a metal layer formed on the surface of the substrate. (1) comprises a member selected from a stainless steel plate, a steel plate, a copper plate, a brass plate or an aluminum plate. (1) is constituted by a glass, a ceramic or a synthetic resin. A metal selected from Au, Ag, Cu, and Al constitutes the metal layer. The tartrate comprises sodium tartrate or sodium potassium tartrate. (B1) contains the nitrate ion, indium ion and tartrate at a concentration of 0.001-0.5, 0.001-0.5 and 0.00001-0.1 mol/l respectively. The concentration of tartrate is 1/2-1/5 of that of indium ion. The nitrate ion and indium ion are based on an ion supply source comprising indium nitrate contained in (B1). The indium nitrate has a concentration of 0.001 to 0.5 mol/l in (B1).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: (A1) contains a carbohydrate comprising at least a material selected from sucrose, dextrin, glucose, maltose, fructose, galactose, lactose, glycogen, or inulin. The tartrate comprises sodium tartrate or sodium potassium tartrate. EXAMPLE - An optically reflective layer of a silver-film (1,000 Angstrom) was formed on 430BA (stainless steel plate substrate) by DC magnetron sputtering without heating the substrate. The substrate having the optically reflective layer was positioned in the film-forming apparatus as the negative electrode. Indium oxide film (5,000 Angstrom) was formed on the optically reflective layer as the first transparent and electrically conductive layer by using indium nitrate as the aqueous solution at a concentration of 0.02 mol/l and film formation was conducted for 25 minutes while maintaining the aqueous solution at 30 degreesC. The first conductive layer was positioned in RF plasma chemical vapor deposition apparatus. A semiconductor active layer was formed on conductive layer by sequentially forming n-type amorphous silicon semiconductor layer (250 Angstrom) with the use of SiH4 gas, H2 gas and PH3 gas at respective flow rates of 5, 10 and 0.001 sccm; i-type amorphous silicon semiconductor layer (2,000 Angstrom) with the use of SiH4 gas and H2 gas at respective flow rates of 5 and 10 sccm; and p-type microcrystalline silicon semiconductor layer (150 Angstrom) with the use of SiH4 gas, H2 gas and BF3 gas at respective flow rates of 5, 1,500 and 5 sccm. On the p-type microcrystalline silicon semiconductor layer a thick In2O3-SnO2 (ITO) film (660 Angstrom) was formed by a conventional heat resistance evaporation process in which an In source and a Sn source were evaporated in an O2 atmosphere. On the ITO film an Ag film was formed in a cruciate form at a thickness of 3,000 Angstrom as the grid electrode to obtain a solar cell. A comparative solar cell was prepared in the same manner except that indium oxide film (5,000 Angstrom) obtained by DC magnetron sputtering without heating the substrate was used as the first transparent and electroconductive layer. The test/comparative solar cells were subjected to measurements under pseudo sunlight having an intensity of 100 mW/cm2 and a spectrum of AM 1.5. The results showed that the test/comparative had short-circuit current density (mA/cm2) of 11.1/10.5; an open-circuit voltage (v) of 0.95/0.96; a fill factor (F.F.) of 0.68/0.67 and a photoelectric conversion efficiency (%) of 7.2/6.8.