A method for growing a crystalline composition, the first crystalline composition may include gallium and nitrogen. The crystalline composition may have an infrared absorption peak at about 3175 cm.sup.1, with an absorbance per unit thickness of greater than about 0.01 cm.sup.1. In one embodiment, the composition ay have an amount of oxygen present in a concentration of less than about 310.sup.18 per cubic centimeter, and may be free of two-dimensional planar boundary defects in a determined volume of the first crystalline composition.

Materials, products, methods of use and fabrication thereof are disclosed. The materials are particularly well suited for application in products such as superconducting devices and quantum computing, due to ability to avoid undesirable effects from inherent noise and decoherence. The materials are formed from select isotopes having zero nuclear spin into a single crystal-phase film or layer of thickness depending on the desired application of the resulting device. The film/layer may be suspended or disposed on a substrate. The isotopes may be enriched from naturally-occurring sources of isotopically mixed elemental material(s). The single crystal is preferably essentially devoid of structural defects such as grain boundaries, inclusions, impurities and lattice vacancies.

Materials, devices, methods of use and fabrication thereof are disclosed. The materials are particularly well suited for application in superconducting devices and quantum computing, due to ability to avoid undesirable effects from inherent noise and decoherence. The materials are formed from select isotopes having zero nuclear spin into a single crystal-phase film or layer of thickness depending on the desired application of the resulting device. The film/layer may be suspended or disposed on a substrate. The isotopes may be enriched from naturally-occurring sources of isotopically mixed elemental material(s). The single crystal is preferably devoid of structural defects such as grain boundaries, inclusions, impurities and lattice vacancies. Device configurations may be formed from the layer according to a predetermined pattern using lithographic and/or milling techniques. An optional protective layer may be deposited on some or all of the device to avoid formation of oxides and/or patinas on surfaces of the device.

A method of producing nanoparticles comprises effecting conversion of a molecular cluster compound to the material of the nanoparticles. The molecular cluster compound comprises a first ion and a second ion to be incorporated into the growing nanoparticles. The conversion can be effected in the presence of a second molecular cluster compound comprising a third ion and a fourth ion to be incorporated into the growing nanoparticles, under conditions permitting seeding and growth of the nanoparticles via consumption of a first molecular cluster compound.

A method of forming an organic solid crystal (OSC) thin film includes forming a layer of a non-volatile medium material over a surface of a mold, forming a layer of a molecular feedstock over a surface of the non-volatile medium material, the molecular feedstock including an organic solid crystal precursor, forming crystal nuclei from the organic solid crystal precursor, and growing the crystal nuclei to form the organic solid crystal thin film. An organic solid crystal (OSC) thin film may include a biaxially-oriented organic solid crystal layer having mutually orthogonal refractive indices, n.sub.1?n.sub.2?n.sub.3.

A method of producing nanoparticles comprises effecting conversion of a nanoparticle precursor composition to the material of the nanoparticles. The nanoparticle precursor composition comprises a first precursor species containing a group 13 element to be incorporated into the nanoparticles and a separate second precursor species containing either a group 15 or a group 16 element to be incorporated into the nanoparticles. The conversion is effected in the presence of molecular cluster compounds under conditions permitting seeding and growth of the nanoparticles on the molecular cluster compounds. The molecular cluster compounds and nanoparticle precursor composition can be dissolved in a solvent at a first temperature to form a solution and the temperature of the solution can then be increased to a second temperature sufficient to initiate seeding and growth of the nanoparticles on the molecular cluster compounds.

A method for growing a crystalline composition, the first crystalline composition may include gallium and nitrogen. The crystalline composition may have an infrared absorption peak at about 3175 cm.sup.1, with an absorbance per unit thickness of greater than about 0.01 cm.sup.1. In one embodiment, the composition may have an amount of oxygen present in a concentration of less than about 310.sup.18 per cubic centimeter, and may be free of two-dimensional planar boundary defects in a determined volume of the first crystalline composition.

Disclosed is a self-supporting zinc oxide substrate composed of a plate composed of a plurality of zinc-oxide-based single crystal grains, wherein the plate has a single crystal structure in an approximately normal direction, and the zinc-oxide-based single crystal grains have a cross-sectional average diameter of greater than 1 m. This substrate can be manufactured by a method comprising providing an oriented polycrystalline sintered body; forming a layer with a thickness of 20 m or greater composed of zinc-oxide-based crystals on the oriented polycrystalline sintered body so that the layer has crystal orientation mostly in conformity with crystal orientation of the oriented polycrystalline sintered body; and removing the oriented polycrystalline sintered body to obtain the self-supporting zinc oxide substrate. The present invention can provide a self-supporting zinc oxide substrate being inexpensive and also suitable for having a large area as a preferable alternative material for a zinc oxide single crystal substrate.

A two-dimensional perovskite forming material with an ammonium halide group disposed on its surface can achieve a high carrier mobility. Preferably, the two-dimensional perovskite forming material includes a monolayer that has such an ammonium halide group at a terminal of its molecular structure, and the ammonium halide group in the monolayer is disposed in an ordered fashion on the surface of the material.

A disc-like GaN substrate is a substrate produced by a tiling method and having an angel between the normal line and m-axis on the main surface of the substrate of 0 to 20 inclusive and a diameter of 45 to 55 mm, to 4 or less. In a preferred embodiment, a disc-like GaN substrate has a first main surface and a second main surface that is opposite to the first main surface, and which has an angle between the normal line and m-axis on the first main surface of 0 to 20 inclusive and a diameter of 45 mm or more. The disc-like GaN substrate comprises at least four crystalline regions each being exposed to both of the first main surface and the second main surface, wherein the four crystalline regions are arranged in line along the direction of the orthogonal projection of c-axis on the first main surface.