Abstract: A solar cell having a first subcell including a germanium (Ge) substrate having a diffusion region doped with n-type dopants including phosphorus and arsenic, wherein the upper portion of such diffusion region has a higher concentration of phosphorus (P) atoms than arsenic (As) atoms, and a second subcell including a layer of either gallium arsenide (GaAs) or indium gallium arsenide (InGaAs) disposed over the substrate.

Abstract: Methods of fabricating multijunction solar cells that may include providing a substrate, and depositing a nucleation first layer over and directly in contact with the substrate. The methods may also include depositing a second layer containing an arsenic dopant over the nucleation layer. The nucleation layer may serve as a diffusion barrier to the arsenic dopant such that diffusion of the arsenic dopant into the substrate is limited in depth by the nucleation layer. The methods may also include depositing a sequence of layers over the second layer forming at least one solar subcell.

Abstract: A multijunction solar cell is fabricated according to an embodiment by providing a substrate, depositing a nucleation first layer over and directly in contact with the substrate, depositing a second layer containing an arsenic dopant over the nucleation layer and depositing a sequence of layers over the second layer forming at least one solar subcell. The nucleation layer serves as a diffusion barrier to the arsenic dopant such that diffusion of the arsenic dopant into the substrate is limited in depth by the nucleation layer.

Abstract: Dopant diffusion into semiconductor material is controlled during fabrication of a semiconductor structure by depositing a nucleation layer over a first layer of the semiconductor structure and depositing a device layer containing the dopant over the nucleation layer. The nucleation layer serves as a diffusion barrier by limiting in depth the diffusion of the dopant into the first layer. The dopant can include arsenic (As).

Abstract: Apparatus and Method for Optimizing the Efficiency of Germanium Junctions in Multi-Junction Solar Cells. In a preferred embodiment, an indium gallium phosphide (InGaP) nucleation layer is disposed between the germanium (Ge) substrate and the overlying dual-junction epilayers for controlling the diffusion depth of the n-doping in the germanium junction. Specifically, by acting as a diffusion barrier to arsenic (As) contained in the overlying epilayers and as a source of n-type dopant for forming the germanium junction, the nucleation layer enables the growth time and temperature in the epilayer device process to be minimized without compromising the integrity of the dual-junction epilayer structure. This in turn allows the arsenic diffusion into the germanium substrate to be optimally controlled by varying the thickness of the nucleation layer.

Abstract: A seal for a continuous casting furnace having a melting chamber with a mold therein for producing a metal cast includes a passage between the melting chamber and external atmosphere. As the cast moves through the passage, the cast outer surface and the passage inner surface define therebetween a reservoir for containing liquid glass or other molten material to prevent the external atmosphere from entering the melting chamber. Particulate material fed into the reservoir is melted by heat from the cast to form the molten material. The molten material coats the cast as it moves through the passage and solidifies to form a coating to protect the hot cast from reacting with the external atmosphere. Preferably, the mold has an inner surface with a cross-sectional shape to define a cross-sectional shape of the cast outer surface whereby these cross-sectional shapes are substantially the same as a cross-sectional shape of the passage inner surface.

Abstract: A seal for a continuous casting furnace having a melting chamber with a mold therein for producing a metal cast includes a passage between the melting chamber and external atmosphere. As the cast moves through the passage, the cast outer surface and the passage inner surface define therebetween a reservoir for containing liquid glass or other molten material to prevent the external atmosphere from entering the melting chamber. Particulate material fed into the reservoir is melted by heat from the cast to form the molten material. The molten material coats the cast as it moves through the passage and solidifies to form a coating to protect the hot cast from reacting with the external atmosphere. Preferably, the mold has an inner surface with a cross-sectional shape to define a cross-sectional shape of the cast outer surface whereby these cross-sectional shapes are substantially the same as a cross-sectional shape of the passage inner surface.

Abstract: Apparatus and Method for Optimizing the Efficiency of Germanium Junctions in Multi-Junction Solar Cells. In a preferred embodiment, an indium gallium phosphide (InGaP) nucleation layer is disposed between the germanium (Ge) substrate and the overlying dual-junction epilayers for controlling the diffusion depth of the n-doping in the germanium junction. Specifically, by acting as a diffusion barrier to arsenic (As) contained in the overlying epilayers and as a source of n-type dopant for forming the germanium junction, the nucleation layer enables the growth time and temperature in the epilayer device process to be minimized without compromising the integrity of the dual-junction epilayer structure. This in turn allows the arsenic diffusion into the germanium substrate to be optimally controlled by varying the thickness of the nucleation layer.

Abstract: A seal for a continuous casting furnace having a melting chamber with a mold therein for producing a metal cast includes a passage between the melting chamber and external atmosphere. As the cast moves through the passage, the cast outer surface and the passage inner surface define therebetween a reservoir for containing liquid glass or other molten material to prevent the external atmosphere from entering the melting chamber. Particulate material fed into the reservoir is melted by heat from the cast to form the molten material. The molten material coats the cast as it moves through the passage and solidifies to form a coating to protect the hot cast from reacting with the external atmosphere. Preferably, the mold has an inner surface with a cross-sectional shape to define a cross-sectional shape of the cast outer surface whereby these cross-sectional shapes are substantially the same as a cross-sectional shape of the passage inner surface.

Abstract: A casting furnace for preheating and melting solid feed material includes a melting chamber with a melting hearth therein and a feed chamber in fluid communication with the melting chamber for conveying the solid material into the melting chamber. A heat source melts the feed material within the melting hearth and produces surplus heat used to preheat the solid feed material. Preferably, gas is heated by the heat source and moved into the feed chamber to preheat the feed material while it is conveyed toward the melting hearth. The heated gas is recycled back into the melting chamber to be re-heated therein and reused to preheat additional feed material in the feed chamber. Where the heat source in the melting chamber includes a plasma torch, the gas is recycled via the plasma torch, which ionizes the gas to create a plasma plume for melting the solid material.

Abstract: A seal for a continuous casting furnace having a melting chamber with a mold therein for producing a metal cast includes a passage between the melting chamber and external atmosphere. As the cast moves through the passage, the cast outer surface and the passage inner surface define therebetween a reservoir for containing liquid glass or other molten material to prevent the external atmosphere from entering the melting chamber. Particulate material fed into the reservoir is melted by heat from the cast to form the molten material. The molten material coats the cast as it moves through the passage and solidifies to form a coating to protect the hot cast from reacting with the external atmosphere. Preferably, the mold has an inner surface with a cross-sectional shape to define a cross-sectional shape of the cast outer surface whereby these cross-sectional shapes are substantially the same as a cross-sectional shape of the passage inner surface.

Abstract: A geothermal fill material composed of one or more high heat conductivity materials alone or in combination to produce a fill that can be used to cover and encapsulate geothermal ground coils to improve heat transfer between the ground and the fluid inside the coils and to improve the rate of heat recovery of the fill in contact and in the vicinity of the coils. These materials can be in the form of particulates, rods or wire mesh and in any combination. Further enhancements are to cover this high conductivity material with low conductivity materials near the surface of the ground or to install the coils in a ground coil field below a structure in order to reduce ground heat loss to the atmosphere in the winter and to reduce heat gain from the atmosphere in the summer.

Abstract: Geothermal ground coils are installed and embedded in fill at the bottom of excavations, made for drainage fields associated with septic and other effluent systems, prior to the addition of the drainage field sanitary fill. This configuration eliminates the need for expensive bore holes and provides a ground heat source that is at a higher temperature than natural ground formations due to the supplemental heat imparted to the ground by the drain field effluent Fouling of the outside heat transfer surfaces of the ground coils is also avoided because of the clarifying and filtering action of the drain field fill. This provides an improved ground source heat pump system wherein the installation costs are reduced arid the capacity and efficiency of the system are improved.

Abstract: A seal for a continuous casting furnace having a melting chamber with a mold therein for producing a metal cast includes a passage between the melting chamber and external atmosphere. As the cast moves through the passage, the cast outer surface and the passage inner surface define therebetween a reservoir for containing liquid glass or other molten material to prevent the external atmosphere from entering the melting chamber. Particulate material fed into the reservoir is melted by heat from the cast to form the molten material. The molten material coats the cast as it moves through the passage and solidifies to form a coating to protect the hot cast from reacting with the external atmosphere. Preferably, the mold has an inner surface with a cross-sectional shape to define a cross-sectional shape of the cast outer surface whereby these cross-sectional shapes are substantially the same as a cross-sectional shape of the passage inner surface.

Abstract: In a preferred embodiment, an indium gallium phosphide (InGaP) nucleation layer is disposed between the germanium (Ge) substrate and the overlying dual-junction epilayers for controlling the diffusion depth of the n-doping in the germanium junction. Specifically, by acting as a diffusion barrier to arsenic (As) contained in the overlying epilayers and as a source of n-type dopant for forming the germanium junction, the nucleation layer enables the growth time and temperature in the epilayer device process to be minimized without compromising the integrity of the dual-junction epilayer structure. This in turn allows the arsenic diffusion into the germanium substrate to be optimally controlled by varying the thickness of the nucleation layer. An active germanium junction formed in accordance with the present invention has a typical diffused junction depth that is ? to ½ of that achievable in prior art devices.

Abstract: A method of manufacturing titanium electrodes in a vacuum arc remelting furnace as well as a reusable header for use in the remelting process is disclosed. An electrode may be attached to the reusable header and remelted in the furnace a number of times until a final ingot of the desired metallurgical quality is produced. The header and electrode are provided with a complimentarily shaped interlocking recess and projection to secure them together. The electrode may alternatively be integrally formed with a starter stub that includes a recess or projection that interlocks with a complimentarily shaped projection or recess on the header. At least a section of the header is made of the same metal as the electrode to be melted to reduce contamination of the ingot being formed in the furnace. Alternatively the starter stub is made from the same metal as the electrode.

Abstract: A recessed rim cold hearth and flanged skull for producing refined metal from raw metal contaminated with high density inclusions and/or hard alpha particles. The hearth has a hollowed body with a rectangular bottom wall and respective upstanding rectangular side and end walls which have imbedded water pipes for cooling water to circulate. An upwardly open chamber is defined within the body which terminates at an upper rim for holding a skull of metal formed on the cooled walls of the hearth. The upper rim of the hearth has an upwardly open, inwardly disposed peripheral recess to form and receive an outwardly extending peripheral flange of solidified metal of the skull.

Abstract: Apparatus and Method for Optimizing the Efficiency of Germanium Junctions in Multi-Junction Solar Cells. In a preferred embodiment, an indium gallium phosphide (InGaP) nucleation layer is disposed between the germanium (Ge) substrate and the overlying dual-junction epilayers for controlling the diffusion depth of the n-doping in the germanium junction. Specifically, by acting as a diffusion barrier to arsenic (As) contained in the overlying epilayers and as a source of n-type dopant for forming the germanium junction, the nucleation layer enables the growth time and temperature in the epilayer device process to be minimized without compromising the integrity of the dual-junction epilayer structure. This in turn allows the arsenic diffusion into the germanium substrate to be optimally controlled by varying the thickness of the nucleation layer.