Abstract: A system for disinfecting fluid includes a plurality of fluid reactors. Each of the fluid reactors includes at least one UVC LED. The UVC LED includes an LED chip configured to emit UVC radiation and a package coupled with the LED chip. The LED chip has a top surface that defines a chip top surface area. The top surface is formed from a semiconductor material having an index of refraction. The fluid reactor has at least one wall that defines a chamber configured to contain the fluid. The at least one wall has an aperture configured to receive UVC radiation into the chamber. The aperture extends through the at least one wall. The aperture has an aperture area that is (1) smaller than a top surface area of the package and (2) equal to or larger than the chip top surface area.

Abstract: A system for disinfecting fluid includes a UVC LED. The UVC LED includes an LED chip configured to emit UVC radiation and a package coupled with the LED chip. The LED chip has a top surface that defines a chip top surface area. The top surface is formed from a semiconductor material having an index of refraction. The fluid reactor has at least one wall that defines a chamber configured to contain the fluid. The at least one wall has an aperture configured to receive UVC radiation into the chamber. The aperture extends through the at least one wall. The aperture has an aperture area that is (1) smaller than a top surface area of the package and (2) equal to or larger than the chip top surface area.

Abstract: A system for disinfecting fluid includes a plurality of fluid reactors. Each of the fluid reactors includes at least one UVC LED. The UVC LED includes an LED chip configured to emit UVC radiation and a package coupled with the LED chip. The LED chip has a top surface that defines a chip top surface area. The top surface is formed from a semiconductor material having an index of refraction. The fluid reactor has at least one wall that defines a chamber configured to contain the fluid. The at least one wall has an aperture configured to receive UVC radiation into the chamber. The aperture extends through the at least one wall. The aperture has an aperture area that is (1) smaller than a top surface area of the package and (2) equal to or larger than the chip top surface area.

Abstract: A system for disinfecting fluid includes a UVC LED. The UVC LED includes an LED chip configured to emit UVC radiation and a package coupled with the LED chip. The LED chip has a top surface that defines a chip top surface area. The top surface is formed from a semiconductor material having an index of refraction. The fluid reactor has at least one wall that defines a chamber configured to contain the fluid. The at least one wall has an aperture configured to receive UVC radiation into the chamber. The aperture extends through the at least one wall. The aperture has an aperture area that is (1) smaller than a top surface area of the package and (2) equal to or larger than the chip top surface area.

Abstract: Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm?2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Abstract: Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm?2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Abstract: Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm?2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Abstract: Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm?2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Abstract: Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm?2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Abstract: Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density?100 cm?2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

Abstract: Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm?2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Abstract: Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density?100 cm?2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

Abstract: A method and apparatus for producing bulk single crystals of AlN having low dislocation densities of about 10,000 cm?2 or less includes a crystal growth enclosure with Al and N2 source material therein, capable of forming bulk crystals. The apparatus maintains the N2 partial pressure at greater than stoichiometric pressure relative to the Al within the crystal growth enclosure, while maintaining the total vapor pressure in the crystal growth enclosure at super-atmospheric pressure. At least one nucleation site is provided in the crystal growth enclosure, and provision is made for cooling the nucleation site relative to other locations in the crystal growth enclosure. The Al and N2 vapor is then deposited to grow single crystalline low dislocation density AlN at the nucleation site. High efficiency ultraviolet light emitting diodes and ultraviolet laser diodes are fabricated on low defect density AlN substrates, which are cut from the low dislocation density AlN crystals.

Abstract: According to one aspect of the invention, an improved process for preparing a surface of substrate is provided wherein the surface of the substrate is prepared for a chemical mechanical polishing (CMP) process, the CMP process is performed on the surface of the substrate, and the surface of the substrate is finished to clear the substrate surface of any active ingredients from the CMP process. Also, an improved substrate produced by the method is provided. According to one aspect of the invention, particular polishing materials and procedures may be used that allow for increased quality of AlN substrate surfaces.

Abstract: Fabrication of doped and undoped stoichiometric polycrystalline AlN ceramics with high purity is accomplished by, for example, reacting Al pellets with nitrogen gas. Such polycrystalline AlN ceramics may be utilized in the fabrication of high purity AlN single crystals, which may be annealed to enhance a conductivity thereof.

Abstract: Fabrication of doped AlN crystals and/or AlGaN epitaxial layers with high conductivity and mobility is accomplished by, for example, forming mixed crystals including a plurality of impurity species and electrically activating at least a portion of the crystal.

Abstract: Reducing the microvoid (MV) density in AlN ameliorates numerous problems related to cracking during crystal growth, etch pit generation during the polishing, reduction of the optical transparency in an AlN wafer, and, possibly, growth pit formation during epitaxial growth of AlN and/or AlGaN. This facilitates practical crystal production strategies and the formation of large, bulk AlN crystals with low defect densities—e.g., a dislocation density below 104 cm?2 and an inclusion density below 104 cm?3 and/or a MV density below 104 cm?3.

Abstract: Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm?2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.

Abstract: Fabrication of AlN substrates suitable for epitaxial deposition of high-quality nitride-based compounds thereon having at least one single-crystal and substantially planarized useful area exceeding about 1 cm2 with a peak-to-valley surface topography in the useful area being less than about 50 nm is accomplished by, for example, employing an active solution that reacts non-selectively with the substrate material.

Abstract: A method and apparatus for producing bulk single crystals of AlN having low dislocation densities of about 10,000 cm?2 or less includes a crystal growth enclosure with Al and N2 source material therein, capable of forming bulk crystals. The apparatus maintains the N2 partial pressure at greater than stoichiometric pressure relative to the Al within the crystal growth enclosure, while maintaining the total vapor pressure in the crystal growth enclosure at super-atmospheric pressure. At least one nucleation site is provided in the crystal growth enclosure, and provision is made for cooling the nucleation site relative to other locations in the crystal growth enclosure. The Al and N2 vapor is then deposited to grow single crystalline low dislocation density AlN at the nucleation site. High efficiency ultraviolet light emitting diodes and ultraviolet laser diodes are fabricated on low defect density AlN substrates, which are cut from the low dislocation density AlN crystals.