Abstract: An apparatus including a crucible, an energy source, and a controller is provided. The crucible may be sealed to a nitrogen-containing gas, and may be chemically inert to at least ammonia at a temperature in a range of about 400 degrees Celsius to about 2500 degrees Celsius. The energy source may supply thermal energy to the crucible. The controller may control the energy source to selectively direct sufficient thermal energy to a predefined first volume within the crucible to attain and maintain a temperature in the first volume to be in a range of from about 400 degrees Celsius to about 2500 degrees Celsius. The thermal energy may be sufficient to initiate, sustain, or both initiate and sustain growth of a crystal in the first volume. The first temperature in the first volume may be controllable separately from a second temperature in another volume within the crucible. The first temperature and the second temperature differ from each other. Associated methods are provided.

Abstract: A single crystal or quasi-single crystal including one or more Group III material and an impurity. The impurity includes one or more elements from Group IA, Group IIA, Groups IIIB to VIIB, Group VIII, Group IB, Group IIB, or Group VIIA elements of the periodic table of elements. A composition for forming a crystal is also provided. The composition includes a source material comprising a Group III element, and a flux comprising one or more of P, Rb, Cs, Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Pd, Ag, Hf, Ta, W, Pt, Au, Hg, Ge, or Sb; or the flux may comprise a rare earth metal.

Abstract: A capsule for containing at least one reactant and a supercritical fluid in a substantially air-free environment under high pressure, high temperature processing conditions. The capsule includes a closed end, at least one wall adjoining the closed end and extending from the closed end; and a sealed end adjoining the at least one wall opposite the closed end. The at least one wall, closed end, and sealed end define a chamber therein for containing the reactant and a solvent that becomes a supercritical fluid at high temperatures and high pressures. The capsule is formed from a deformable material and is fluid impermeable and chemically inert with respect to the reactant and the supercritical fluid under processing conditions, which are generally above 5 kbar and 550° C. and, preferably, at pressures between 5 kbar and 80 kbar and temperatures between 550° C. and about 1500° C.

Abstract: A GaN crystal having up to about 5 mole percent of at least one of aluminum, indium, and combinations thereof. The GaN crystal has at least one grain having a diameter greater than 2 mm, a dislocation density less than about 104 cm?2, and is substantially free of tilt boundaries.

Abstract: A flip chip light emitting diode die (10, 10?, 10?) includes a light-transmissive substrate (12, 12?, 12?) and semiconductor layers (14, 14?, 14?) that are selectively patterned to define a device mesa (30, 30?, 30?). A reflective electrode (34, 34?, 34?) is disposed on the device mesa (30, 30?, 30?). The reflective electrode (34, 34?, 34?) includes a light-transmissive insulating grid (42, 42?, 60, 80) disposed over the device mesa (30, 30?, 30?), an ohmic material (44, 44?, 44?, 62) disposed at openings of the insulating grid (42, 42?, 60, 80) and making ohmic contact with the device mesa (30, 30?, 30?), and an electrically conductive reflective film (46, 46?, 46?) disposed over the insulating grid (42, 42?, 60, 80) and the ohmic material (44, 44?, 44?, 62). The electrically conductive reflective film (46, 46?, 46?) electrically communicates with the ohmic material (44, 44?, 44?, 62).

Abstract: In a method for producing a resonant cavity light emitting device, a seed gallium nitride crystal (14) and a source material (30) are arranged in a nitrogen-containing superheated fluid (44) disposed in a sealed container (10) disposed in a multiple-zone furnace (50). Gallium nitride material is grown on the seed gallium nitride crystal (14) to produce a single-crystal gallium nitride substrate (106, 106?). Said growing includes applying a temporally varying thermal gradient (100, 100?, 102, 102?) between the seed gallium nitride crystal (14) and the source material (30) to produce an increasing growth rate during at least a portion of the growing. A stack of group III-nitride layers (112) is deposited on the single-crystal gallium nitride substrate (106, 106?), including a first mirror sub-stack (116) and an active region (120) adapted for fabrication into one or more resonant cavity light emitting devices (108, 150, 160, 170, 180).

Abstract: The present invention is directed toward a method for fabricating low-defect nanostructures of wide bandgap materials and to optoelectronic devices, such as light emitting sources and lasers, based on them. The invention utilizes nanolithographically-defined templates to form nanostructures of wide bandgap materials that are energetically unfavorable for dislocation formation. In particular, this invention provides a method for the fabrication of phosphor-less monolithic white light emitting diodes and laser diodes that can be used for general illumination and other applications.

Abstract: A photodetector (100, 200, 300) comprising a gallium nitride substrate, at least one active layer (104, 302) disposed on the substrate (102, 202, 306), and a conductive contact structure (106, 210, 308) affixed to the active layer (104, 302) and, in some embodiments, the substrate (102, 202, 306). The invention includes photodetectors (100, 200, 300) having metal-semiconductor-metal structures, P-i-N structures, and Schottky-barrier structures. The active layers (104, 302) may comprise Ga1-x-yAlxInyN1-z-w PzAsw, or, preferably, Ga1-xAlxN. The gallium nitride substrate comprises a single crystal gallium nitride wafer and has a dislocation density of less than about 105 cm?2. A method of making the photodetector (100, 200, 300) is also disclosed.