Abstract: Patterned substrates for photovoltaic and other uses are made by pressing a flexible stamp upon a thin layer of resist material, which covers a substrate, such as a wafer. The resist changes phase or becomes flowable, flowing away from locations of impression, revealing the substrate, which is subjected to some shaping process, typically etching. Portions exposed by the stamp being are removed, moved, and portions that protected by the resist, remain. A typical substrate is silicon, and a typical resist is a wax. Workpiece textures include extended grooves, discrete, spaced apart pits, and combinations and intermediates thereof. Platen or rotary patterning apparatus may be used. Rough and irregular workpiece substrates may be accommodated by extended stamp elements. Resist may be applied first to the workpiece, the stamp, or substantially simultaneously, in discrete locations, or over the entire surface of either. The resist dewets the substrate completely where desired.

Abstract: Methods of manufacturing an article use three-dimensional printing for a portion of the manufacturing. Three-dimensionally printing is conducted onto a powder bed which contains both organic-solvent-soluble, water-insoluble particles and water soluble, organic-solvent-insoluble particles. The water-soluble particles which may be selected for properties such as size and may include more than one substance. The organic-solvent-insoluble particles may further include at least one substantially insoluble substance such as a member of the calcium phosphate family. Printing may be done using an aqueous binder liquid. After removal of unbound powder, the preform may be exposed to the vapor of an organic solvent which causes the particles of organic-soluble-polymer to fuse to each other. This may further be followed by dissolving out the water-soluble particles, if such particles were present in the powder.

Abstract: Semiconductor photovoltaic cells have surfaces that are textured for processing and photovoltaic reasons. The absorbing regions may have parallel grooves that reduce loss of solar energy that would otherwise be lost by reflection. One form of texturing has parallel grooves and ridges. The cell also includes regions of metallization for collecting the generated electrical carriers and conducting them away, which may be channels. The topography is considered during production, using a process that takes advantage of the topography to govern what locations upon will receive a specific processing, and which locations will not receive such a processing. Liquids are treated directly into zones of the cell. They migrate throughout a zone and act upon the locations contacted. They do not migrate to other zones, due to impediments to fluid flow that are features of the surface texture, such as edges, walls and ridges.

Abstract: An original wafer, typically silicon, has the form of a desired end PV wafer. The original may be made by rapid solidification or CVD. It has small grains. It is encapsulated in a clean thin film, which contains and protects the silicon when recrystallized to create a larger grain structure. The capsule can be made by heating a wafer in the presence of oxygen, or steam, resulting in silicon dioxide on the outer surface, typically 1-2 microns. Further heating creates a molten zone in space, through which the wafer travels, resulting in recrystallization with a larger grain size. The capsule contains the molten material during recrystallization, and protects against impurities. Recrystallization may be in air. Thermal transfer through backing plates minimizes stresses and defects. After recrystallization, the capsule is removed.

Abstract: Methods of manufacturing an article use three-dimensional printing for a portion of the manufacturing. Three-dimensionally printing is conducted onto a powder bed which contains both organic-solvent-soluble, water-insoluble particles and water soluble, organic-solvent-insoluble particles. The water-soluble particles which may be selected for properties such as size and may include more than one substance. The organic-solvent-insoluble particles may further include at least one substantially insoluble substance such as a member of the calcium phosphate family. Printing may be done using an aqueous binder liquid. After removal of unbound powder, the preform may be exposed to the vapor of an organic solvent which causes the particles of organic-soluble-polymer to fuse to each other. This may further be followed by dissolving out the water-soluble particles, if such particles were present in the powder.

Abstract: A system for producing a crystal formed from a material with impurities has a crucible for containing the material. The crucible has, among other things, a crystal region for forming the crystal, an introduction region for receiving the material, and a removal region for removing a portion of the material. The crucible is configured to produce a generally one directional flow of the material (in liquid form) from the introduction region toward the removal region. This generally one directional flow causes the removal region to have a higher concentration of impurities than the introduction region.

Abstract: A steel powder metal skeleton is infiltrated with an infiltrant composition similar to the skeleton, with an additional agent that depresses the melting point of the infiltrant relative to the skeleton. Infiltration is driven primarily by capillary pressure. The powder and infiltrant compositions differ primarily only in a higher concentration of a melting point depressant agent “MPD” in the infiltrant. Carbon (C) and silicon (Si) and several other elements can be elements in an MPD, either alone or in combination. Certain steel target compositions are such that a complementary infiltrant, and skeleton can be chosen such that a skeleton will remain solid at an infiltration temperature at which the infiltrant can be melted and fully infiltrated, and further where there is a persistent two phase field, with a liquid phase that is large enough (greater than 7% vol, and typically between 20 and 40 vol %) so that flow can be maintained without choke off from diffusional solidification.

Abstract: A drop on demand printer has a nozzle with an orifice and a surrounding annular land. Surrounding the land is an edge, which is surrounded by a perimetrical surface that is inclined to the land at an angle ?. A pressure controller maintains a positive overpressure on liquid to be printed such that a cap of liquid is substantially always present covering the orifice and the land. The edge between the land and the perimetrical surface prevents liquid from overflowing, and maintains the cap, if the pressure is maintained between lower and upper limits disclosed. The liquid to be printed preferably wets the orifice land, which may be alumina, glass, ceramic, and others. Liquids with very small, even zero, wetting angles relative to the land may be used, such as water and organic solvents, including, isopropyl and ethyl alcohol and chloroform. The liquid can be loaded with dissolved polymers, or particles, such as of polymer or ceramic.

Abstract: An infiltrant is used to fill a metal powder skeleton. The infiltrant is similar in composition to the base powder, but contains a melting point depressant. The infiltrant will quickly fill the powder skeleton, then as the melting point depressant diffuses into the base powder, the liquid will undergo solidification and the material will eventually homogenize. This process allows more accurate control of dimensions in large parts with uniform or homogeneous microstructure or bulk properties.

Abstract: A drop on demand printer has a nozzle with an orifice and a surrounding annular land. Surrounding the land is an edge, which is surrounded by a perimetrical surface that is inclined to the land at an angle &agr;. A pressure controller maintains a positive overpressure on liquid to be printed such that a cap of liquid is substantially always present covering the orifice and the land. The edge between the land and the perimetrical surface prevents liquid from overflowing, and maintains the cap, if the pressure is maintained between lower and upper limits disclosed. The liquid to be printed preferably wets the orifice land, which may be alumina, glass, ceramic, and others. Liquids with very small, even zero, wetting angles relative to the land may be used, such as water and organic solvents, including, isopropyl and ethyl alcohol and chloroform. The liquid can be loaded with dissolved polymers, or particles, such as of polymer or ceramic.

Abstract: In infiltrating a porous metal skeleton an infiltrant composition is used similar to that of the powder skeleton, but with the addition of a melting point depressant. The infiltrant quickly fills the skeleton. As the melting point depressant diffuses into the base powder, the liquid may undergo diffusional solidification and the material eventually homogenizes. Maintaining the infiltrant at a liquidus composition for the infiltration temperature typically ensures that the bulk composition or properties will remain uniform throughout the part, particularly in the direction of infiltration. Success of such an infiltration is enhanced by effective means of maintaining the molten infiltrant at a liquidus composition. It is also beneficial, in some cases, for the time scale of the infiltration to be much faster than the time scale of the diffusion of the melting point depressant and the subsequent solidification and homogenization.

Abstract: In infiltrating a porous metal skeleton an infiltrant composition is used similar to that of the powder skeleton, but with the addition of a melting point depressant. The infiltrant quickly fills the skeleton. As the melting point depressant diffuses into the base powder, the liquid may undergo diffusional solidification and the material eventually homogenizes. Maintaining the infiltrant at a liquidus composition for the infiltration temperature typically ensures that the bulk composition or properties will remain uniform throughout the part, particularly in the direction of infiltration. Success of such an infiltration is enhanced by effective means of maintaining the molten infiltrant at a liquidus composition. It is also beneficial, in some cases, for the time scale of the infiltration to be much faster than the time scale of the diffusion of the melting point depressant and the subsequent solidification and homogenization.

Abstract: An infiltrant is used to fill a metal powder skeleton. The infiltrant is similar in composition to the base powder, but contains a melting point depressant. The infiltrant will quickly fill the powder skeleton, then as the melting point depressant diffuses into the base powder, the liquid will undergo solidification and the material will eventually homogenize. This process allows more accurate control of dimensions in large parts with uniform or homogeneous microstructure or bulk properties.

Abstract: A new mold solves problems that arise from differential changes in geometry inherent to casting metal in a ceramic mold, by control of the internal morphology between the surfaces of the mold that face the casting, and that face the external environment. Layered fabrication techniques are used to create a ceramic mold. For example, an internal geometry composed of a cellular arrangement of voids may be created within the mold wall. Structures may be designed and fabricated so that the ceramic mold fails at an appropriate time during the solidification and/or cooling of the casting. Thus, the casting itself is not damaged. The mold fails to avoid rupture, or even distortion, of the casting. A thin shell of ceramic defines the casting cavity. This shell must be thin enough to fail due to the stresses induced (primarily compressive) by the metal next to it and partly adherent to it.

Abstract: In infiltrating a porous metal skeleton an infiltrant composition is used similar to that of the powder skeleton, but with the addition of a melting point depressant. The infiltrant quickly fills the skeleton. As the melting point depressant diffuses into the base powder, the liquid, may undergo diffusional solidification and the material eventually homogenizes. Maintaining the infiltrant at a liquidus composition for the infiltration temperature typically ensures that the bulk composition or properties will remain uniform throughout the part, particularly in the direction of infiltration. Success of such an infiltration is enhanced by effective means of maintaining the molten infiltrant at a liquidus composition. It is also beneficial, in some cases, for the time scale of the infiltration to be much faster than the time scale of the diffusion of the melting point depressant and the subsequent solidification and homogenization.

Abstract: A powder bed (32) is built up by repeated deposition of a slurry that contains powder. Layers are made by depositing a liquid dispersion of the desired powdered material, which then slip-casts into the forming powder bed to make a new layer (34). The slurry may be deposited in any suitable manner, such as by raster or vector scanning, or by a plurality of simultaneous jets that coalesce before the liquid slip-casts into the bed, or by individual drops, the deposits of which are individually controlled, thereby generating a regular surface for each layer.

Abstract: Parts made from powder use a material that originates from a salt to bind powder particles together. The salt may be provided dissolved in a solution, as molten salt, or as a dry powder. The figure is an electron micrograph of a cross section of a silver nitrate bound product with a skeleton of steel powder.

Abstract: A new mold solves problems that arise from differential changes in geometry inherent to casting metal in a ceramic mold, by control of the internal morphology between the surfaces of the mold that face the casting, and that face the external environment. Layered fabrication techniques are used to create a ceramic mold. For example, an internal geometry composed of a cellular arrangement of voids may be created within the mold wall. Structures may be designed and fabricated so that the ceramic mold fails at an appropriate time during the solidification and/or cooling of the casting. Thus, the casting itself is not damaged. The mold fails to avoid rupture, or even distortion, of the casting.

Abstract: A new mold solves problems that arise from differential changes in geometry inherent to casting metal in a ceramic mold, by control of the internal morphology between the surfaces of the mold that face the casting, and that face the external environment. Layered fabrication techniques are used to create a ceramic mold. For example, an internal geometry composed of a cellular arrangement of voids may be created within the mold wall. Structures may be designed and fabricated so that the ceramic mold fails at an appropriate time during the solidification and/or cooling of the casting. Thus, the casting itself is not damaged. The mold fails to avoid rupture, or even distortion, of the casting. A thin shell of ceramic defines the casting cavity. This shell must be thin enough to fail due to the stresses induced (primarily compressive) by the metal next to it and partly adherent to it.

Abstract: The invention features a method of continuous crystalline growth. A granular source material is introduced into a hopper. A volume of the granular source material exiting the hopper is disposed on a translationally moving belt. The volume of the granular source material forms an angle of repose with the moving belt. The granular source material disposed on the moving belt is continuously fed into a crucible comprising a melt of the granular source material at a rate based on the angle of repose, the speed of the belt, and the size of the opening of the hopper. A crystalline ribbon is continuously grown by solidifying the melt.