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: In various embodiments, a rigid lens is attached to a light-emitting semiconductor die via a layer of encapsulant having a thickness insufficient to prevent propagation of thermal expansion mismatch-induced strain between the rigid lens and the semiconductor die.

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: A compact power supply and battery substitute has a cylindrical wall with combustion air and cooling air fans at opposite ends. Air and fuel vapor flows through a mixing tube and an Omega recuperator to a combustion chamber and heats IR emitters spaced from TPV cells. An emitter post array or a catalytic matched emitter are heated by combustion. Exhaust is conducted through the recuperator that heats secondary air and fuel vapors and air in a mixing tube. Cooling air flows over fins radially extending from the TPV cells and past the recuperator and, mixes with exhaust from the recuperators and flows out of the housing past the combustion air fan. Fans are self-powered, and resulting electric power replaces batteries.

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: A one-axis azimuth sun-tracking carousel where the PV panels are mounted at a fixed tilt in operation can be mounted on a flat roof building without roof penetration and without risk of wind damage. The carousel is prefabricated and sized to carry the maximum power while still fitting in a standard shipping container. Panel support arms fold down for shipping or in the event of a hurricane to make the carousel less than 9 inches high. Because this carousel is prefabricated and compact, it can be easily hoisted up on a roof for rapid low-cost installation. Wind skirts provide low wind resistance in high wind situations during normal operation. In order to survive high winds without roof penetration, wire tether tie points allow several carousels in an array to be tethered together and to the building parapet walls.

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: 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 crystal of aluminum nitride (AlN) having an a real 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: Semiconductor structures and devices based thereon include an aluminum nitride single-crystal substrate and at least one layer epitaxially grown thereover. The epitaxial layer may comprise at least one of AlN, GaN, InN, or any binary or tertiary alloy combination thereof, and have an average dislocation density within the semiconductor heterostructure is less than about 106 cm?2.

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: In accordance with various embodiments, crystalline structures are formed by providing, at a growth temperature, a liquid comprising AlN and having a quality factor greater than approximately 0.14 and forming solid AlN from the liquid, the growth temperature being lower than the melting point of AlN.