Abstract: Apparatus for production of semiconductor ribbon materials of the type in which molten material is brought into contact with the surface of a rotating cool wheel or drum wherein the cooling surface of the drum is textured to form a plurality of discrete contacting points to enhance growth of large crystal grains.

Abstract: An improved solar cell, and method for manufacture, in which a back side reverse p-n junction is formed prior to metallization and a gridded back side metallization material, chosen so that it penetrates the p-n junction where it is present, is fired into the wafer. The finished solar cell has improved efficiency despite the presence of the reverse p-n junction over a majority of the back face surface.

Abstract: A tundish for use in casting a ribbon of crystalline or coarse grain polycrystalline material, having a support for a hopper containing molten material, the hopper having a bottom plate and three side wall plates and a top plate, each made of a material which will not interact with the molten material contained within the space defined by the bottom plate, side wall plates and top plate, to impart any significant impurity into the molten material, and wherein the top plate slants downwardly towards the bottom plate to form an elongated orifice through which molten material is extruded onto a cool surface where crystallization of a ribbon of material occurs. As disclosed, the top plate is movable with respect to the bottom plate to change the thickness of the orifice. Also as disclosed, the top plate slides in a slot in each of two opposed side walls and is of a length such that it forms with the third side wall an opening into which molten material is added to the tundish.

Abstract: Apparatus and method for producing semiconductor ribbon directly from the molten state by contact with a moving chill surface wherein water vapor is introduced to improve ribbon top surface smoothness.

Abstract: Apparatus and method for producing semiconductor ribbon directly from the molten state by contact with a moving chill surface wherein the chill surface has longitudinal grooves near its outer edges to define ribbon width and improve smoothness of ribbon edges.

Abstract: A solar cell has a rear electrical contact for the semiconductor body of the cell forming an intersecting pattern which includes rows of contact pads which are parallel to a pair of sides of the body; a set of contact strips which also are parallel to such sides; another set of contact strips which are parallel to another pair of sides of the body perpendicular to the first pair of sides; and yet another set of contact strips which are angularly oriented with respect to both pairs of sides of the body. The contact pattern permits the passage of radiation through the cell which would otherwise decrease efficiency due to heat generation and incorporates additional features designed to balance a desire for transparency to such radiation with a requirement for efficient charge collection along the rear of the cell.

Abstract: A method and apparatus for casting material into a ribbon shape in which molten material to be cast is extruded in a thin ribbon onto a moving sheet of foil of a metal having a sufficiently lower melting point or which forms an alloy with the molten material which has a sufficiently lower melting point than the molten material, to cause almost immediate melting of at least a portion of the foil which comes in contact with the ribbon of molten casting material, with crystallization of the cast material occuring on a layer of liquified foil or foil-cast material alloy. Also disclosed is the disposing of the metal foil, in the vicinity of the contact with the ribbon of molten casting material, on a cooled surface which is moving past the region of extrusion of the molten material. The method and apparatus is disclosed to be particularly useful in making cast ribbon of semiconductor material with a foil backing and desirable properties for photovoltaic solar cell applications.

Abstract: A take-up reel and take-up reel starting feed for use in high speed ribbon crystallization of molten material e.g., a metal or a semiconductor material, in which a starting strip is pre-wound onto the take-up reel sufficiently to frictionally engage the take-up reel and be thereby drawn onto the take-up reel from a supply reel for the starting strip, and wherein the linear velocity of the starting strip in a contact zone is synchronized with the linear velocity of a cast ribbon of the material leaving a rotating drum on which the casting initiated, so that the ribbon of cast material, after it passes over the starting strip in the contact zone, will contact the starting strip and pass onto the take-up reel in contact with the starting strip and without bunching or significant stretching of the ribbon of cast material.