Abstract:
In an exemplary embodiment, tape-shaped silicon bodies for solar cells are formed by continuous coating of a carrier body having a mesh structure. A melt bath receives the silicon melt and has a floor part with capillary openings therein for supplying the melt, the capillary openings leading perpendicularly toward the exterior of the vat and proceeding parallel to one another, and wherein a channel for the guidance of the carrier body proceeding in a horizontal direction is disposed below the melt vat in the region of the capillary openings. The guide channel for the carrier body can also be disposed above a body with capillaries proceeding parallel in a vertical direction, the body being partially immersed in the vat containing the silicon melt for the purpose of supplying the melt via the capillaries. The devices enable continuous tape drawing from a silicon melt wherein convection currents are avoided in the melt.
Abstract:
Si-crystals with columnar structures are produced by contacting a silicon melt with a melt-resistant carrier body having periodically spaced crystallization-seed centers on a surface thereof facing the melt, establishing a controlled temperature gradient at the interface between the carrier body surface and the melt so that crystallization of the melt onto the seed centers occurs and then removing the body with the adhering crystal layer from the melt. In a preferred embodiment, an elongated traveling web having a select hole pattern therein functioning as the seed centers, is utilized as a carrier body.
Abstract:
A method of producing a light conducting fiber comprises the steps of providing a base member of an optical material such as glass or a synthetic glass-like material, depositing at least one optical material forming layer such as a glass forming layer or a synthetic glass-like material forming layer from a liquid phase on a surface of the base member and subsequently transforming each of the layers into a film of optical material such as a glass film or a synthetic glass-like film. The base member may be a glass tube and the optical material forming layers may be deposited on an interior surface and after the layers have been transformed into a film, the tube is collapsed into a rod and then subsequently drawn into a cladded light conducting fiber. In one embodiment of the invention, the base member is a rod and the layers are deposited on a surface of the rod which is subsequently drawn into a cladded light conducting fiber. In yet another embodiment of the invention, the base member is provided by drawing a core of an optical fiber and the method includes depositing the optical material forming layers on the core so that as the layers are transformed into the film of optical material, a cladded light conducting fiber will be produced.
Abstract:
A method and device for the complete emptying of flat quartz tanks or crucibles filled with silicon melt is provided. The apparatus includes an open outlet nozzle located in a floor of the tank and a tube-shaped, rod-shaped, or channel-shaped member composed of a material that is well-wettable by silicon melt that is brought into contact with the outlet nozzle after the conclusion of the drawing process. The member is in fluid communication with a collecting vessel. The outlet nozzle is so constructed and arranged that the silicon melt adjacent at the nozzle aperture is prevented from running out during the band drawing due to the curvature pressure of its downwardly, convexly arced surface. The apparatus can be used in continuous, horizontal band-drawing of silicon for solar cells.
Abstract:
A method for the manufacture of gallium arsenide thin film solar cells on inexpensive substrate material whereby an intermediate layer of highly doped, amorphous germanium is employed in order to promote the growth of the gallium arsenide layers. A high-energy radiation is directed to specific, prescribed points on the highly doped, amorphous germanium layer thereby generating centers having a defined crystal orientation, so that the epitaxial layer spreads laterally from these centers in a surface-covering fashion during the epitaxial vapor phase deposition. The solar cells produced by designational grain growth can be manufactured with high purity in a simple way and have an efficiency (greater than 20%) comparable to known mono-crystalline solar cells.
Abstract:
A method for continuously manufacturing silicon tapes which are predominantly coated on one side of the carrier, for solar cells. In an exemplary embodiment, a carrier body consisting of a graphite network is conducted vertically upwards through a guide channel situated in the floor of a silicon melt bath and travels through a crystallization region where the molten silicon crystallizes on the carrier body. The surfaces of the guide channel at each side of the carrier path in the vicinity of the crystallization region are wetted by the molten silicon and have different dimensions in a direction at right angles to the carrier path. As a result of the differential in surface tension forces at the two sides of the path, a meniscus is formed which is asymmetrical relative to the channel opening thereby causing asymmetrical coating of the carrier body.
Abstract:
A method for the production of single-material light-guiding fibers which have a core supported in a glass sheath in a cantilever manner by glass webs characterized by providing a crucible having an exit nozzle with an opening having a configuration of the cross section of the light-guiding fiber with a core portion connected by web portions to a surrounding annular portion, providing molten material of the light-guiding fiber in the crucible, drawing the molten material from the crucible through the exit nozzle to form a continuous integral workpiece having a core portion supported in a glass sheath in a cantilever manner by integral glass webs and continuously drawing the integral workpiece into the single-material light-guiding fiber. The crucible is formed by a pair of hollow bodies supported in an outer cylindrical member in a cantilever manner so that the cylindrical member and the pair of hollow bodies form the exit nozzle with the desired configuration.
Abstract:
A new solar cell of a I-III-VI.sub.2 semiconductor material that has an inversion layer is provided. The cell comprises a substrate having an electrically conductive, first electrode, a p-conductive, polycrystalline semiconductor layer of chalcopyrite material, a barrier layer composed of an electrically non-conductive material, a second electrode, and an antireflection layer. The anti-reflection layer has stationary, positive charges that induce a negatively charged inversion layer in the boundary surface region of the semiconductor layer relative to the barrier layer. The negatively charged inversion layer serves as an emitter for a space charge zone. In an embodiment the invention comprises a semiconductor layer of copper-indium-diselenide or copper-gallium-diselenide, a barrier layer of silicon dioxide, an anti-reflection layer of silicon nitride, and cesium chloride as the stationary charges.
Abstract:
An improved method of forming porous glass preforms by generating glass particles from a vapor phase and applying the particles onto a substrate characterized by generating the glass particles from a vapor phase in a separate operation, collecting the particles and then subsequently applying the previously collected particles onto a deposition surface of the substrate by creating a hot zone adjacent the deposition surface and projecting the particles as a stream through the hot zone and onto the deposition surface.
Abstract:
Starting plate-like silicon bodies matched to the dimensions desired in a product silicon crystal bodies are melted and then crystallized on a horizontal carrier member having a net structure using a heater arrangement. The carrier member is substantially not wettable by molten silicon and preferably consists of a quartz glass fiber fabric and is removable after the crystallization. The method is useful for the manufacture of silicon for solar cells and prevents contaminants from the carrier member from being incorporated into the product silicon crystal body and thereby deteriorating the electrical properties of the solar cells.