Methods for modifying the surface termination of two-dimensional (2D) transition metal carbides (MXenes) are provided. The methods, which allow for versatile chemical modification of the terminating anions via halide exchange or substitution and elimination reactions in molten inorganic salts, provide a processing approach that is widely applicable to MXenes as a broad class of functional materials.

A niobium compound and a method of forming a thin film using the niobium compound, the compound being represented by the following General formula I: ##STR00001## wherein, in General formula I, R.sup.1, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are each independently a hydrogen atom, a C1-C6 linear or branched alkyl group or a C3-C6 cyclic hydrocarbon group, at least one of R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 being a C1-C6 linear or branched alkyl group, and R.sup.2 and R.sup.3 are each independently a hydrogen atom, a halogen atom, a C1-C6 linear or branched alkyl group, or a C3-C6 cyclic hydrocarbon group.

A group III nitride crystal, wherein the group III nitride crystal is doped with an N-type dopant and a germanium element, the concentration of the N-type dopant is 1×10.sup.19 cm.sup.−3 or more, and the concentration of the germanium element is nine times or more higher than the concentration of the N-type dopant.

A group III nitride crystal, wherein the group III nitride crystal is doped with an N-type dopant and a germanium element, the concentration of the N-type dopant is 1×10.sup.19 cm.sup.−3 or more, and the concentration of the germanium element is nine times or more higher than the concentration of the N-type dopant.

Described herein are Group V and VI compounds used as precursors for depositing Group V and VI-containing films. Ligands with alkyl, amide, imide, amidinate groups and/or cyclopentadienyl (Cp) ligands are used to form Group V and VI complexes used as precursors. Examples of Group V and VI precursor compounds include, but are not limited to, Cp amide imide alkyl vanadium compounds, Cp amide imide alkylamide vanadium compounds, Cp amide imide alkoxide vanadium compounds, Cp amide imide amidinate vanadium compounds, and alkylimide vanadium trichloride compounds. The Group V and VI precursors are used for deposition on substrate surfaces with superior film properties such as uniformity, continuity, and low resistance. Examples of substrate surfaces for deposition of metal-containing films include, but are not limited to metals, metal oxides, and metal nitrides.

Proposed is a method for removing phosphorus from a phosphorus-containing substance which is applicable in an industrial scale so as to effectively reduce phosphorus contained in the phosphorus-containing substance. In this method, the phosphorus-containing substance used as a raw material for metal smelting or metal refining is reacted with a nitrogen-containing gas at a treatment temperature T (° C.) which is lower than a melting temperature (T.sub.m) of the substance, so that phosphorus is removed preferably in the form of phosphorus nitride (PN). In this regard, a nitrogen partial pressure and an oxygen partial pressure in the nitrogen-containing gas are preferably controlled, thereby reducing a load of dephosphorization process, for example.

A micro-electro-mechanical systems (MEMS) sensor includes a substrate, a diaphragm portion and a piezoelectric film. The diaphragm portion is located at the substrate. The piezoelectric film is located on the diaphragm portion. The piezoelectric film is made of scandium aluminum nitride. A carbon concentration of the piezoelectric film is 2.5 atomic percent or less while an oxygen concentration of the piezoelectric film is 0.35 atomic percent or less.

Provided is a method for producing a phosphor, using a nitride raw material, that gives a high-reliability (Sr,Ca)AlSiN.sub.3-based nitride phosphor at a productivity higher than before. The method comprises a mixing step of mixing raw materials and a calcining step of calcining the mixture obtained in the mixing step and, in producing the phosphor having a crystalline structure substantially identical with that of (Sr,Ca)AlSiN.sub.3 crystal as the host crystal, a strontium nitride containing SrN, Sr.sub.2N, or the mixture thereof as the main crystalline phase, as determined by crystalline phase analysis by powder X-ray diffractometry, and having a nitrogen content of 5 to 12 mass % is used as part of the raw materials.

There is provided a method of manufacturing a group III nitride semiconductor substrate including: a fixing step S10 of fixing abase substrate, which includes a group III nitride semiconductor layer having a semipolar plane as a main surface, to a susceptor; a first growth step S11 of forming a first growth layer by growing a group III nitride semiconductor over the main surface of the group III nitride semiconductor layer in a state in which the base substrate is fixed to the susceptor using an HVPE method; a cooling step S12 of cooling a laminate including the susceptor, the base substrate, and the first growth layer; and a second growth step S13 of forming a second growth layer by growing a group III nitride semiconductor over the first growth layer in a state in which the base substrate is fixed to the susceptor using the HVPE method.

A general procedure applied to a variety of sol-gel precursors and solvent systems for preparing and controlling homogeneous dispersions of very small particles within each other. Fine homogenous dispersions processed at elevated temperatures and controlled atmospheres make a ceramic powder to be consolidated into a component by standard commercial means: sinter, hot press, hot isostatic pressing (HIP), hot/cold extrusion, spark plasma sinter (SPS), etc.