TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The method (I) further comprises: depositing a second thin-film layer comprising a semiconductor second material chemically different from the first material; a second laser heating to form a second seed spot; extending the second seed spot into a second single-crystal seed line in the second thin-film semiconductor layer by laser-heating at least one crystallization zone adjacent to the seed spot and drawing the crystallization zone across the second thin-film layer; extending the single crystal seed line across the second thin-film layer by laser-heating a crystallization zone adjacent to the seed line and thawing the crystallization zone across the second thin-film layer; depositing a third thin-film layer of a semiconductor third material chemically different from the first and second materials; a third laser heating to form a third seed spot; extending the third seed spot into a third single-crystal seed line in the third thin-film layer by laser-heating the crystallization zone adjacent to the seed spot and drawing the crystallization zone across the third thin-film layer; and extending the single crystal seed line across the third thin-film semiconductor layer by laser-heating a crystallization zone adjacent to the seed line and thawing the crystallization zone across the third thin-film layer. The method (II) further comprising: depositing second thin-film semiconductor layer, where the second thin-film semiconductor layer has an initial microstructure comprising amorphous, nanocrystalline or microcrystalline; laser-heating to crystallization temperature a seed spot of the second thin-film semiconductor layer, where the seed spot having size on the order of a critical size of nucleation of the second thin-film semiconductor layer, and thus crystallizing the seed spot into a single-crystal seed; extending the seed spot into a second single-crystal seed line by laser-heating the crystallization zone adjacent to the seed spot and drawing the crystallization zone across the second thin-film semiconductor layer; extending the second single crystal seed line across the thin-film semiconductor layer by laser-heating crystallization zone adjacent to the second seed line and drawing the crystallization zone across the second thin-film semiconductor layer; and constructing a second junction using the second thin-film semiconductor layer. The step of laser heating is performed after the step of depositing the second semiconductor material, and both the first and second thin-film layers are crystallized during the step of laser heating. The step of laser heating is performed prior to depositing the second thin-film layer. The thin-film semiconductor layer comprises at least a first and a second sublayer, and the step of extending the seed line crystallizes at least the first, but not the second, sublayer. Preferred Components: The thin-film material layer comprises a material comprising silicon, germanium, gallium arsenide, gallium phosphide, indium gallium phosphide, cadmium telluride, copper indium gallium di-selenide, cupric or cuprous oxide, zinc oxide, zinc phosphide or indium gallium nitride. The thin-film material has amorphous initial microstructure. The thin-film material comprises primarily silicon. The surface is substrate comprising a non-single-crystal material including glass, plastics, metal or ceramics. The surface comprises a template layer comprising a non-single-crystal material including silicon oxide, silicon nitride, silicon oxynitride or amorphous silicon. The seed spot has size of 1-1000 nm. The seed spot has size of not greater than twice the critical size of nucleation. EXAMPLE - No suitable example given.