Abstract: A method of removing buffer gas from a mixture comprising the buffer gas and hyperpolarized noble gas is described. The method includes reacting the buffer gas to produce a reaction product different to the buffer gas. The buffer gas may be reactively removed by one or more of oxidation, reduction, polymerization and binding reactions with solid surfaces. The buffer gas may be molecular hydrogen and/or molecular nitrogen. Apparatus for carrying out the method are also disclosed.

Abstract: Provided are group-III nitride nanoparticles that prevent the piezoelectric field caused by strains on the nanoparticles, achieving good luminous efficiency. The group-III nitride nanoparticle represented by AlxGayInzN (0?x, y, z?1) incorporating two crystal structures; a wurtzite structure and a zincblende structure, in a single particle. As another example, the group-III nitride nanoparticle has a core-shell structure with a core and a shell, in which the particle constituting the core contains two crystal structures; the wurtzite structure and the zincblende structure, in the particle. Nanoparticles containing the two crystal structures can be produced by using a phosphorus-containing solvent as a reaction solvent, and the mixture ratio of the two crystal structures, (wurtzite structure)/(zincblende structure), is 20/80 or higher.

Abstract: There is provided a nitride crystal substrate constituted by group-III nitride crystal, containing n-type impurities, with an absorption coefficient ? being approximately expressed by equation (1) by a least squares method in a wavelength range of at least 1 ?m or more and 3.3 ?m or less. ?=NeK?a??(1) (where 1.5×10?19?K?6.0×10?19, a=3), here, a wavelength is ? (?m), an absorption coefficient of the nitride crystal substrate at 27° C. is ? (cm?1), a carrier concentration in the nitride crystal substrate is Ne (cm?3), and K and a are constants, wherein an error of an actually measured absorption coefficient with respect to the absorption coefficient ? obtained from equation (1) at a wavelength of 2 ?m is within ±0.1?, and in a reflection spectrum measured by irradiating the nitride crystal substrate with infrared light, there is no peak with a peak top within a wavenumber range of 1,200 cm?1 or more and 1,500 cm?1 or less.

Abstract: The present invention provides a gallium nitride sintered body and a gallium nitride molded article which have high density and low oxygen content without using a special apparatus. According to the first embodiment, a gallium nitride sintered body, which is characterized by having density of 2.5 g/cm3 to less than 5.0 g/cm3 and an intensity ratio of the gallium oxide peak of the (002) plane to the gallium nitride peak of the (002) plane of less than 3%, which is determined by X-ray diffraction analysis, can be obtained. According to the second embodiment, a metal gallium-impregnated gallium nitride molded article, which is characterized by comprising a gallium nitride phase and a metal gallium phase that exist as separate phases and having a molar ratio, Ga/(Ga+N), of 55% to 80%, can be obtained.

Abstract: The present disclosure provides an open Czochralski furnace for single crystal growth. The crystal growth apparatus may include a furnace chamber which includes a furnace body and a furnace cover. The furnace cover may be mounted on a top of the furnace body. The furnace cover may include a first through hole. The first through hole may be configured to place a temperature field. The crystal growth apparatus in the present disclosure can solve a problem that a traditional vacuum furnace needs to firstly pump a high vacuum and secondly recharge a protecting gas, thereby improving the apparatus safety; simplify the structure of the furnace body such that components that need maintenance and repair can be disassembled quickly, thereby reducing manufacturing and maintenance costs; improve the operation accuracy and stability of the apparatus; and reduce the influence of heat convection on the stability of weighing signals in the open furnace.

Abstract: A method for printing a semiconductor material includes depositing a molten metal onto a substrate in an enclosed chamber to form a trace having a maximum height of 15 micrometers, a maximum width of 25 micrometers to 10 millimeters, and/or a thin film having a maximum height of 15 micrometers. The method further includes reacting the molten metal with a gas phase species in the enclosed chamber to form the semiconductor material.

Abstract: The present invention provides a zinc nitride compound suitable for electronic devices such as high-speed transistors, high-efficiency visible light-emitting devices, high-efficiency solar cells, and high-sensitivity visible light sensors. The zinc nitride compound is represented, for example, by the chemical formula CaZn2N2 or the chemical formula X12ZnN2 wherein X1 is Be or Mg. The zinc nitride compound is preferably synthesized at a high pressure of 1 GPa or more.

Abstract: Disclosed is a method for facilitating preparation of high quality crystals suitable for X-ray crystallographic studies. The method comprises that an electric charge or current is provided to a saturated solution of the molecule to be crystallized, preferably via a jet of gaseous ions. Also disclosed is an assembly for carrying out the method of the invention.

Abstract: The ammonia synthesis catalyst of the present invention, comprises: a powder of a perovskite oxyhydride having hydride (H?) incorporated therein as a support; and a metal or a metal compound exhibiting a catalytic activity for ammonia synthesis, supported on the support, and the perovskite oxyhydride is represented by ATiO3-xHx (wherein A represents Ca, Sr, or Ba, and 0.1?x?0.6).

Abstract: A semiconductor stack includes a substrate composed of a III-V group compound semiconductor, a buffer layer that is arranged on the substrate and that is composed of a III-V group compound semiconductor, and an active layer that is arranged on the buffer layer and that includes a layer composed of a III-V group compound semiconductor containing Sb as a group V element. A region of the buffer layer including a main surface of the buffer layer adjacent to the substrate includes a high-concentration region having a high total concentration of Si and C compared with another adjacent region.

Abstract: A catalytic composition from earth-abundant transition metal salts and biomass is disclosed. A calcined catalytic composition formed from soybean powder and ammonium molybdate is specifically exemplified herein. Methods for making the catalytic composition are disclosed as are electrodes for hydrogen evolution reactions comprising the catalytic composition.

Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.

Abstract: A GaN-crystal free-standing substrate obtained from a GaN crystal grown by HVPE with a (0001) plane serving as a crystal growth plane and at least one plane of a {10-11} plane and a {11-22} plane serving as a crystal growth plane that constitutes a facet crystal region, except for the side surface of the crystal, wherein the (0001)-plane-growth crystal region has a carbon concentration of 5×1016 atoms/cm3 or less, a silicon concentration of 5×1017 atoms/cm3 or more and 2×1018 atoms/cm3 or less, and an oxygen concentration of 1×1017 atoms/cm3 or less; and the facet crystal region has a carbon concentration of 3×1016 atoms/cm3 or less, a silicon concentration of 5×1017 atoms/cm3 or less, and an oxygen concentration of 5×1017 atoms/cm3 or more and 5×1018 atoms/cm3 or less.

Abstract: An ammonothermal growth of group-III nitride crystals on starting seed crystals with at least two surfaces making an acute, right or obtuse angle, i.e., greater than 0 degrees and less than 180 degrees, with respect to each other, such that the exposed surfaces together form a concave surface.

Abstract: A nitride crystal which encircles an outer periphery of a seed crystal, the nitride crystal in an embodiment includes: a first partial region, and a second partial region that has optical characteristics different from those of the first partial region and has optical characteristics which indicate the crystal orientation.

Abstract: A high-quality nitride crystal can be produced efficiently by charging a nitride crystal starting material that contains tertiary particles having a maximum diameter of from 1 to 120 mm and formed through aggregation of secondary particles having a maximum diameter of from 100 to 1000 ?m, in the starting material charging region of a reactor, followed by crystal growth in the presence of a solvent in a supercritical state and/or a subcritical state in the reactor, wherein the nitride crystal starting material is charged in the starting material charging region in a bulk density of from 0.7 to 4.5 g/cm3 for the intended crystal growth.

Abstract: It is provided a method of producing a crystal of a nitride of a group 13 element in a melt by flux method. The melt is generated by heating a composition including a material for the group 13 element, a material for at least one of an alkali metal and an alkaline earth metal and a liquid material for germanium. Upon producing a crystal of a nitride of a group 13 element in a melt by flux method, it is thereby possible to reduce in-plane distribution of a property such as carrier density of the thus obtained crystal of a nitride of a group 13 element.

Abstract: A hydrogen-free amorphous dielectric insulating film having a high material density and a low density of tunneling states is provided. The film is prepared by e-beam deposition of a dielectric material on a substrate having a high substrate temperature Tsub under high vacuum and at a low deposition rate. In an exemplary embodiment, the film is amorphous silicon having a density greater than about 2.18 g/cm3 and a hydrogen content of less than about 0.1%, prepared by e-beam deposition at a rate of about 0.1 nm/sec on a substrate having Tsub=400° C. under a vacuum pressure of 1×10?8 Torr.

Abstract: Methods are provided for deposition of films comprising manganese on surfaces using metal coordination complexes comprising an amidoimino-based ligand. Certain methods comprise exposing a substrate surface to a manganese precursor, and exposing the substrate surface to a co-reagent.

Abstract: A system and method for passive capture of ammonia in an ammonia-containing liquid effluent. The invention allows for the passage of ammonia through microporous hydrophobic gas-permeable membranes and its capture in a circulated stripping solution with concomitant production of a concentrated non-volatile ammonium salt.

Abstract: A periodic table Group 13 metal nitride crystals grown with a non-polar or semi-polar principal surface have numerous stacking faults. The purpose of the present invention is to provide a period table Group 13 metal nitride crystal wherein the occurrence of stacking faults of this kind are suppressed. The present invention achieves the foregoing by a periodic table Group 13 metal nitride crystal being characterized in that, in a Qx direction intensity profile that includes a maximum intensity and is derived from an isointensity contour plot obtained by x-ray reciprocal lattice mapping of (100) plane of the periodic table Group 13 metal nitride crystal, a Qx width at 1/300th of peak intensity is 6×10?4 rlu or less.

Abstract: A population of light-emissive nitride nanoparticles has a photoluminescence quantum yield of at least 10% and an emission spectrum having a full width at half maximum intensity (FWHM) of less than 100 nm. One suitable method of producing light-emissive nitride nanoparticles comprises a first stage of heating a reaction mixture consisting essentially of nanoparticle precursors in a solvent, the nanoparticle precursors including at least one metal-containing precursor and at least one first nitrogen-containing precursor, and maintaining the reaction mixture at a temperature to seed nanoparticle growth. It further comprises a second stage of adding at least one second nitrogen-containing precursor to the reaction mixture thereby to promote nanoparticle growth.

Abstract: The present invention discloses a method of synthesizing transition metal nitride by using supercritical ammonia. Transition metal nitride such as vanadium nitride, molybdenum nitride, titanium nitride, nickel nitride, neodymium nitride, iron nitride, etc. can be synthesized in supercritical ammonia with reducing mineralizers such as potassium, sodium, lithium, magnesium, calcium, and aluminum. Since supercritical ammonia has characteristics of both gas and liquid, it can over complicated fine structure or fine particles. The new method is suitable for forming a protective coating on complicated structure or forming micro- to nano-sized particles.

Abstract: Disclosed herein are near field transducers (NFTs) that include either silver, copper, or aluminum and one or more secondary elements.

Abstract: A device including a near field transducer, the near field transducer including gold (Au) and at least one other secondary atom, the at least one other secondary atom selected from: boron (B), bismuth (Bi), indium (In), sulfur (S), silicon (Si), tin (Sn), hafnium (Hf), niobium (Nb), manganese (Mn), antimony (Sb), tellurium (Te), carbon (C), nitrogen (N), and oxygen (O), and combinations thereof erbium (Er), holmium (Ho), lutetium (Lu), praseodymium (Pr), scandium (Sc), uranium (U), zinc (Zn), and combinations thereof and barium (Ba), chlorine (Cl), cesium (Cs), dysprosium (Dy), europium (Eu), fluorine (F), gadolinium (Gd), germanium (Ge), hydrogen (H), iodine (I), osmium (Os), phosphorus (P), rubidium (Rb), rhenium (Re), selenium (Se), samarium (Sm), terbium (Tb), thallium (Th), and combinations thereof.

Abstract: There is provided a magnet manufacturing method with which a high residual magnetic flux density is obtained without using dysprosium (Dy) and without using a bonding agent. Magnetic powders made of a hard magnetic material formed of a R—Fe—N compound containing a rare earth element as R or formed of a Fe—N compound are used. In a pressurizing step, the magnetic powders are pressurized by molds multiple times to form a primary compact. In a baking step, a secondary compact is formed by heating the primary compact in an oxidizing atmosphere at a temperature lower than a decomposition temperature of the magnetic powders to bond together the outer surfaces of the adjacent magnetic powders with oxide films formed on the outer surfaces of the magnetic powders.

Abstract: When a group III nitride crystal is grown in a pressurized atmosphere of a nitrogen-containing gas from a melt 50 including at least a group III element, nitrogen and an alkali metal or an alkali earth metal, a melt-holding vessel 160 that holds the above-described melt 50 is swung about two axes different in direction from each other such as an X-axis and a Y-axis.

Abstract: Group III nitride crystal produced by cutting, from III nitride bulk crystal, a plurality of Group III nitride crystal substrates with major-surface plane orientation misoriented five degrees or less with respect to a crystal-geometrically equivalent plane orientation selected from the group consisting of {20-21}, {20-2-1}, {22-41}, and {22-4-1}, transversely arranging the substrates adjacent to each other such that their major surfaces are parallel to each other and such that their [0001] directions coincide with each other, and growing a Group III nitride crystal on the major surfaces. The Group III nitride crystal substrates are further characterized by satisfying at least either an oxygen-atom concentration of 1×1016 cm?3 to 4×1019 cm?3 or a silicon-atom concentration of 6×1014 cm?3 to 5×1018 cm?3, and by having a carrier concentration of 1×1016 cm?3 to 6×1019 cm?3.

Abstract: The present invention provides a method for producing a Group III nitride crystal, capable of producing a Group III nitride crystal in a large size with few defects and high quality.

Abstract: Flexible semiconductor devices based on flexible freestanding epitaxial elements are disclosed. The flexible freestanding epitaxial elements provide a virgin as grown epitaxy ready surface for additional growth layers. These flexible semiconductor devices have reduced stress due to the ability to flex with a radius of curvature less than 100 meters. Low radius of curvature flexing enables higher quality epitaxial growth and enables 3D device structures. Uniformity of layer formation is maintained by direct absorption of actinic radiation by the flexible freestanding epitaxial element within a reactor. In addition, standard post processing steps like lithography are enabled by the ability of the devices and elements to be flattened using a secondary support element or vacuum. Finished flexible semiconductor devices can be flexed to a radius of curvature of less than 100 meters. Nitrides, Zinc Oxides, and their alloys are preferred materials for the flexible freestanding epitaxial elements.

Abstract: A method of producing an n-type group III nitride single crystal includes putting raw materials that include at least a substance including a group III element, an alkali metal, and boron oxide into a reaction vessel; melting the boron oxide by heating the reaction vessel to a melting point of the boron oxide; forming a mixed melt which includes the group III element, the alkali metal, and the boron oxide, in the reaction vessel by heating the reaction vessel to a crystal growth temperature of a group III nitride; dissolving nitrogen into the mixed melt by bringing a nitrogen-containing gas into contact with the mixed melt; and growing an n-type group III nitride single crystal, which is doped with oxygen as a donor, from the group III element, the nitrogen, and oxygen in the boron oxide that are dissolved in the mixed melt.

Abstract: A process and apparatus for preparing a nanopowder are presented. The process comprises feeding a reactant material into a plasma reactor in which is generated a plasma flow having a temperature sufficiently high to vaporize the material; transporting the vapor with the plasma flow into a quenching zone; injecting a preheated quench gas into the plasma flow in the quenching zone to form a renewable gaseous condensation front; and forming a nanopowder at the interface between the renewable controlled temperature gaseous condensation front and the plasma flow.

Abstract: A permanent magnet may include a Fe16N2 phase constitution.

Abstract: A plurality of mesoporous metal nitride materials may be formed by a method that includes treating with ammonia (or a related bonded nitrogen and hydrogen containing reducing material) a mixed metal oxide material that comprises at least one first metal that forms an unstable product with ammonia and at least one second metal that forms a stable product with ammonia to form the metal nitride materials that include the second metal but not the first metal. The method contemplates forming metal nitride materials, as well as metal oxynitride materials. A related method that uses a non-bonded nitrogen and hydrogen containing reducing material may yield a mesoporous metal oxide. In particular the at least one metal that forms an unstable product with ammonia comprises zinc metal.

Abstract: For a Periodic Table Group 13 metal nitride semiconductor crystal obtained by epitaxial growth on the main surface of a base substrate that has a nonpolar plane and/or a semipolar plane as its main surface, an object of the present invention is to provide a high-quality semiconductor crystal that has a low absorption coefficient, is favorable for a device, and is controlled dopant concentration in the crystal, and to provide a production method that can produce the semiconductor crystal. A high-quality Periodic Table Group 13 metal nitride semiconductor crystal that has a precisely controlled dopant concentration within the crystal and a low absorption coefficient and that is thus favorable for a device, can be provided by inhibiting oxygen doping caused by impurity oxygen and having the Si concentration higher than the O concentration.

Abstract: Affords Group-III nitride single-crystal ingots and III-nitride single-crystal substrates manufactured utilizing the ingots, as well as methods of manufacturing III-nitride single-crystal ingots and methods of manufacturing III-nitride single-crystal substrates, wherein the incidence of cracking during length-extending growth is reduced. Characterized by including a step of etching the edge surface of a base substrate, and a step of epitaxially growing onto the base substrate hexagonal-system III-nitride monocrystal having crystallographic planes on its side surfaces. In order to reduce occurrences of cracking during length-extending growth of the ingot, depositing-out of polycrystal and out-of-plane oriented crystal onto the periphery of the monocrystal must be controlled.

Abstract: A group 13 nitride crystal of hexagonal crystal including at least one or more metal atom selected from the group consisting of B, Al, Ga, In, and Tl, and a nitrogen atom, the group 13 nitride crystal comprises: a first region provided on the inner side of a cross section crossing a c-axis; a third region provided on an outermost side of the cross section; a second region provided between the first region and the third region at the cross section and having characteristics different from characteristics of the first region and the third region, wherein a shape formed by a boundary between the first region and the second region at the cross section is non-hexagonal.

Abstract: The present disclosure generally relates to systems and methods for producing and using Group-III nitride crystals that have enhanced or increase ultraviolet transparency in a range of wavelengths. The crystals may also be used in a number of UV optics and UV optical semiconductor devices.

Abstract: The invention concerns a method for producing a crystalline titanium oxide film useful as a photocatalyst, a photovoltaic element, etc. The crystalline titanium oxide film is produced by steps (a-1) and (b): (a-1) a step of heating titanium or titanium alloy under conditions (1) or (2) to form titanium nitride on the surface of the titanium or titanium alloy; (1) in an atmosphere of nitrogen and/or ammonia gas in the presence of a carbon material acting as an oxygen trapping agent; or (2) in an atmosphere where a pressure is reduced to discharge atmospheric gas, and then nitrogen and/or ammonia gas are/is introduced in the presence of a carbon material acting as an oxygen trapping agent; and (b) a step of immersing the titanium or titanium alloy obtained in step (a-1) above in an electrolyte containing an inorganic acid and/or organic acid, and applying voltage for anodization.

Abstract: Provided is a tantalum sputtering target having a (200)-plane orientation ratio of 70% or less and a (222)-plane orientation ratio of 10% or more at the sputtering surface of the tantalum sputtering target. The sputter rate can be increased by controlling the crystalline orientation of the target, and thereby a film having an intended thickness can be formed in a short time to improve the throughput.

Abstract: There is provided a novel method for producing a nitride single crystal with both a rapid crystal growth rate and high crystal quality, as well as a novel autoclave that can be used in the method. The invention provides a method for producing a Ga-containing nitride single crystal by an ammonothermal method, comprising introducing at least a starting material, an acidic mineralizer and ammonia into an autoclave, and then growing a Ga-containing nitride single crystal under conditions wherein the temperature (T1) at the single crystal growth site is 600° C. to 850° C., the temperature (T1) at the single crystal growth site and the temperature (T2) at the starting material feeder site are in the relationship T1>T2, and the pressure in the autoclave is 40 MPa to 250 MPa, as well as an autoclave that can be used in the method.

Abstract: The present invention is directed to compositions comprising free standing and stacked assemblies of two dimensional crystalline solids, and methods of making the same.

Abstract: Methods and compositions for depositing a metal containing film on a substrate are disclosed. A reactor and at least one substrate disposed in the reactor are provided. A metal containing precursor is provided and introduced into the reactor, which is maintained at a temperature of at least 100° C. A metal is deposited on to the substrate through a deposition process to form a thin film on the substrate.

Abstract: A method of growing high-quality, group-III nitride, bulk single crystals. The group III-nitride bulk crystal is grown in an autoclave in supercritical ammonia using a source material or nutrient that is a group III-nitride polycrystals or group-III metal having a grain size of at least 10 microns or more and a seed crystal that is a group-III nitride single crystal. The group III-nitride polycrystals may be recycled from previous ammonothermal process after annealing in reducing gas at more then 600° C. The autoclave may include an internal chamber that is filled with ammonia, wherein the ammonia is released from the internal chamber into the autoclave when the ammonia attains a supercritical state after the heating of the autoclave, such that convection of the supercritical ammonia transfers source materials and deposits the transferred source materials onto seed crystals, but undissolved particles of the source materials are prevented from being transferred and deposited on the seed crystals.

Abstract: The present invention generally relates to an amorphous semiconductor material and TFTs containing the material. The semiconductor material contains a single cation, such as zinc, and multiple anions. For the multiple anions, only one of the anions can be oxygen or nitrogen. The anions compete with each other to twist the resulting structure. For example, if one of the anions bonded with the cation would result in a cubic structure, and another of the anions bonded with the cation would result in a hexagonal structure, the competing anions would twist the resulting structure so that the structure remains amorphous rather than crystalline. Further, because a single cation is utilized, there is no grain boundary and thus, the material has a high mobility.

Abstract: The present invention relates to ferromagnetic particles capable of exhibiting a high purity and excellent magnetic properties from the industrial viewpoints and a process for producing the ferromagnetic particles, and also provides an anisotropic magnet, a bonded magnet and a compacted magnet which are obtained by using the ferromagnetic particles. The ferromagnetic particles comprising an Fe16N2 compound phase in an amount of not less than 80% as measured by Mössbauer spectrum and each having an outer shell in which FeO is present in the form of a layer having a thickness of not more than 5 nm according to the present invention can be produced by subjecting aggregated particles of an iron compound as a starting material whose primary particles have a ratio of [(average deviation of major axis lengths of particles)/(average major axis length of particles)] of not more than 50%, Uc of not more than 1.55, Cg of not less than 0.95, Cg2 of not less than 0.

Abstract: A hexagonal boron nitride (h-BN) powder is disclosed in which primary particles of the powder exhibit a ratio (D/d) of long diameter (D) to thickness (d) in a range of 5 to 10. Agglomerated particle bodies made of the primary particles have an average particle diameter (D50) in a range of 2 ?m to 200 ?m, inclusive, and the powder has a bulk density in a range of 0.5 g/cm3 to 1.0 g/cm3. In an exemplary method for producing the h-BN, boron carbide is nitridizated in a nitrogen partial pressure of at least 5 kPa at 1800° C. to 2200° C., inclusive. B2O3 (or precursor thereof) is added to the nitridization product to produce a mixture. The mixture is decarbonized in a non-oxidizing atmosphere at a 1500° C. to 2200° C., inclusive. The decarbonization product is pulverized and subject to particle-size classification, yielding H-BN powder. The method includes a depressurizing step, performed at 100 kPa or less either during nitridization or after decarbonization.

Abstract: The present invention relates to a method for preparing nitride nanomaterials, including: providing a first precursor and a second precursor, in which the first precursor is a transition metal precursor, a group IIIA precursor, a group IVA precursor or a mixture thereof, and a second precursor is a nitrogen-containing aromatic compound; and heating the first precursor with the second precursor to form a nitride nanomaterial. Accordingly, the present invention provides a simpler, nontoxic, more widely applied and low-cost method for preparing nitride nanomaterials.

Abstract: Magnetic iron nitride nanoparticles, such as Fe16N2 nanoparticles, are made by subjecting iron nanoparticles synthesized from iron oxide or iron carbonyl precursor to a solid-gas reaction with a nitrogen-containing gas.

Abstract: The present invention is a niobium nitride which has a composition represented by the composition formula Nb3N5 and in which a constituent element Nb has a valence of substantially +5. The method for producing the niobium nitride of the present invention includes the step of nitriding an organic niobium compound by reacting the organic niobium compound with a nitrogen compound gas.