There is provided a nitride crystal substrate constituted by group-III nitride crystal, containing n-type impurities, with an absorption coefficient α being approximately expressed by equation (1) by a least squares method in a wavelength range of at least 1 μm or more and 3.3 μm or less.

[00001]$\begin{array}{cc}\alpha =N_{e}K{\lambda }^a\left(\mathrm{where}1.5\times {10}^{-19}\le K\le 6.0\times {10}^{-19},a=3\right),& \left(1\right)\end{array}$ here, a wavelength is λ (μm), an absorption coefficient of the nitride crystal substrate at 27° C. is α (cm.sup.−1), a carrier concentration in the nitride crystal substrate is N.sub.e (cm.sup.−3), and K and a are constants, wherein an error of an actually measured absorption coefficient with respect to the absorption coefficient α obtained from equation (1) at a wavelength of 2 μm is within +0.1α, 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.sup.−1 or more and 1,500 cm.sup.−1 or less.

A nitride fluorescent material represented by General Formula: MAlSiN.sub.3 (M=Ca, Sr) in which a part of M is substituted with Eu and a main crystal phase has the same structure as that of a CaAlSiN.sub.3 crystal phase, in which a light emission peak wavelength is 640 nm or more, and a half width of the light emission peak wavelength is 80 nm or less.

A surface-coated cutting tool comprises a hard coat layer including a complex nitride layer on the tool substrate. The complex nitride layer has a composition: (Me.sub.1−x−yAl.sub.xM.sub.y)N.sub.z where Me is Ti or Cr, x≤0.80, 0.00≤y≤0.20, 0.20≤(1−x−y)≤0.65, and 0.90≤z≤1.10 (where x, y, and z represents atomic ratios, M is at least one element selected from the group consisting of Groups 4 to 6 elements, Y, Si, La, and Ce in the IUPAC periodic table). The hard coat layer has an interfacial region extending from a point above the surface of the tool substrate and having a thickness in a range of 5 to 100 nm, and the N content to the total of Me, Al, M, and N contents is 10 to 30 atomic % at the point and increases toward the surface of the cutting tool.

The present invention discloses photostable composite of indium gallium nitride and zinc oxide for solar water splitting, comprising Indium content in the range of 1-40 wt %, Ga content in the range of 1 to 15 wt %, nitrogen content in the range of 0.1 to 5 wt %, and the remaining is ZnO. The combustion synthesis comprises the steps of: (a) dissolving 45 to 55 wt % urea, 75 to 80 wt % Zinc nitrate, 3 to 5 wt % Gallium nitrate, and 15 to 20 wt % Indium nitrate in water with stirring until a homogenous solution is formed; and (b) heating the homogenous solution of step (a) at a temperature in the range of 450-550 [deg.]C. for period in the range of 2 to 20 min to obtain the photostable composite.

An aligned film having first and second faces opposed to each other, the aligned film having (a) a plurality of layers aligned non-parallel to the first and second faces between the faces of the aligned film, each layer having a crystal lattice represented by: M.sub.n+1X.sub.n (wherein M is at least one metal of Group 3, 4, 5, 6, or 7; X is a carbon atom, a nitrogen atom, or a combination thereof; and n is 1, 2, or 3), each X is positioned within an octahedral array of M, and at least one of two opposing surfaces of each said layer have at least one modifier or terminal T selected from a hydroxy group, a fluorine atom, an oxygen atom, and a hydrogen atom; and (b) magnetic nanoparticles carried on a layer surface and/or between two adjacent layers of the plurality of layers.

High-purity gallium nitride particles having a low oxygen content suitable for a raw material or a sintered body is provided. Gallium nitride particles characterized in that the oxygen content is 0.5 at % or less and the total impurity amount of elements, Si, Ge, Sn, Pb, Be, Mg, Ca, Sr, Ba, Zn and Cd, is less than 10 wtppm are used.

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 Al.sub.xGa.sub.yIn.sub.zN (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.

Methods and materials are disclosed for simultaneously optimizing both the piezoelectric and mechanical properties of wurtzite piezoelectric materials based on the AlN wurtzite and alloyed with one or two end-members from the set BN, YN, CrN, and ScN.

Disclosed is a composition having nanoparticles or particles of a refractory metal, a refractory metal hydride, a refractory metal carbide, a refractory metal nitride, or a refractory metal boride, an organic compound consisting of carbon and hydrogen, and a nitrogenous compound consisting of carbon, nitrogen, and hydrogen. The composition, optionally containing the nitrogenous compound, is milled, cured to form a thermoset, compacted into a geometric shape, and heated in a nitrogen atmosphere at a temperature that forms a nanoparticle composition comprising nanoparticles of metal nitride and optionally metal carbide. The nanoparticles have a uniform distribution of the nitride or carbide.

Provided is a method for producing a nitride phosphor. The method includes obtaining a first heat-treated product having a crystallite diameter of not less than 150 nm by subjecting a compound containing at least one rare-earth element selected from the group consisting of Y, La, Ce, Lu, and Gd to heat treatment at a temperature within a range of 800° C. to 1800° C.; and obtaining a second heat-treated product by subjecting a mixture containing the first heat-treated product and a raw material contained as required to heat treatment at a temperature within a range of 1200° C. to 1800° C. The raw material contains an M source containing at least one rare-earth element M selected from the group consisting of Y, Lu, and Gd; an La source; an Si source; and a Ce source. The mixture is prepared with the raw materials such that a fed composition is represented by a Formula of La.sub.wM.sub.xSi.sub.6N.sub.y:Ce.sub.z. In this Formula, w, x, y, and z satisfy 0.5≤w≤4.5, 0<x≤1.5, 0≤y≤12, 0<z≤1.5, 0.15<(x+z)<3.0, and 3.0≤(w+x+z)≤7.5.