Abstract: A polycrystalline semiconductor sheet may be converted to a monocrystalline or macrocrystalline semiconductor sheet through use of a geometric restriction in the sheet. The process requires formation of a region of the sheet having a small width compared to the width of the remainder of the sheet. A molten zone is formed in the small width region of the sheet. At least a portion of the molten zone is allowed to solidify into a single crystal or crystals of large size of the semiconductor material coextensive with the small width of the region at the portion of the molten zone so solidified. The molten zone is then moved from the small width region of the sheet into the remainder of the sheet. The sheet is allowed to solidify successively as the molten zone passes along it. As a result, the macrocrystal formed in the narrow width region of the sheet propagates into the remainder of the sheet through which the molten zone passes.

Abstract: A method of producing a sheet of semiconductor material directly usable for the production of solar cells is disclosed. The method comprises establishing a molten region at an edge of a sheet of semiconductor material, moving the molten region across the sheet to create a path of elongated crystal grains, establishing a molten zone along a portion of the path of the elongated crystal grains and parallel thereto, and causing the molten zone to travel in a direction transverse to the path of elongated crystal grains.