A method for effectively removing minute impurities of 1 μm or less in size that are present on a surface of an aluminum nitride single-crystal substrate without etching the surface includes scrubbing a surface of an aluminum nitride single-crystal substrate using a polymer compound material having lower hardness than an aluminum nitride single crystal, and an alkali aqueous solution having 0.01-1 mass % concentration of potassium hydroxide or sodium hydroxide, the alkali aqueous solution being absorbed in the polymer compound material.

The present disclosure is directed to compositions comprising at least one layer having first and second surfaces, each layer comprising: a substantially two-dimensional array of crystal cells, each crystal cell having an empirical formula of M′.sub.2M″nX.sub.n+1, such that each X is positioned within an octahedral array of M′ and M″; wherein M′ and M″ each comprise different Group 11113, WE, VB, or VIB metals; each X is C, N, or a combination thereof; n=1 or 2; and wherein the M′ atoms are substantially present as two-dimensional outer arrays of atoms within the two-dimensional array of crystal cells; the M″ atoms are substantially present as two-dimensional inner arrays of atoms within the two-dimensional array of crystal cells; and the two dimensional inner arrays of M″ atoms are sandwiched between the two-dimensional outer arrays of M′ atoms within the two-dimensional army of crystal cells.

The present disclosure is directed to compositions comprising at least one layer having first and second surfaces, each layer comprising: a substantially two-dimensional array of crystal cells, each crystal cell having an empirical formula of M′.sub.2M″nX.sub.n+1, such that each X is positioned within an octahedral array of M′ and M″; wherein M′ and M″ each comprise different Group 11113, WE, VB, or VIB metals; each X is C, N, or a combination thereof; n=1 or 2; and wherein the M′ atoms are substantially present as two-dimensional outer arrays of atoms within the two-dimensional array of crystal cells; the M″ atoms are substantially present as two-dimensional inner arrays of atoms within the two-dimensional array of crystal cells; and the two dimensional inner arrays of M″ atoms are sandwiched between the two-dimensional outer arrays of M′ atoms within the two-dimensional army of crystal cells.

The invention provides a laminated assembly dedicated to an enhanced heat discharge type electronic device application by providing an enhanced thermal performance to a silicon device. A graphite thin film/silicon substrate laminated assembly is provided by cleaning the surfaces of a smoothed graphite thin film and a silicon substrate under deaeration conditions for activation, thereby bringing them close to each other for spontaneous bonding. In such a laminated assembly wherein the graphite thin film is provided on the silicon substrate, the silicon substrate and graphite thin film come into contact directly via an interface.

A method for manufacturing a nitride semiconductor substrate by using a vapor phase growth method, including: a step of preparing a base substrate of a single crystal of a group III nitride semiconductor and in which a low index crystal plane closest to a main surface is a (0001) plane; an etching step of the base substrate to roughen the main surface; a first step of growing a first layer by epitaxially growing a single crystal of a group III nitride semiconductor on the main surface, and at least some of the plurality of recessed portions being gradually expanded toward an upper side of the main surface of the base substrate, the first layer including a first surface from which the (0001) plane has disappeared and that is constituted only by the inclined interfaces; and a second step of growing a second layer including a mirror second surface.

Disclosed herein methods of forming an Al—Ga containing film comprising: a) exposing a substrate comprising a β-Ga.sub.2O.sub.3, wherein the substrate has a (100) or (−201) orientation, to a vapor phase comprising an aluminum precursor and a gallium precursor; and b) forming a β-(Al.sub.xGa.sub.1-x).sub.2O.sub.3 thin film by a chemical vapor deposition at predetermined conditions and wherein x is 0.01≤x≤0.7. Also disclosed herein are devices comprising the inventive films.

Disclosed herein methods of forming an Al—Ga containing film comprising: a) exposing a substrate comprising a β-Ga.sub.2O.sub.3, wherein the substrate has a (100) or (−201) orientation, to a vapor phase comprising an aluminum precursor and a gallium precursor; and b) forming a β-(Al.sub.xGa.sub.1-x).sub.2O.sub.3 thin film by a chemical vapor deposition at predetermined conditions and wherein x is 0.01≤x≤0.7. Also disclosed herein are devices comprising the inventive films.

A method of forming a plurality of diamonds provides a base, epitaxially forms a first sacrificial layer on the base, and then epitaxially forms a first diamond layer on the first sacrificial layer. The first sacrificial layer has a first material composition, and the first diamond layer is a material that is different from the first material composition. The method then epitaxially forms a second sacrificial layer on the first diamond layer, and epitaxially forms a second diamond layer on the second sacrificial layer. The second sacrificial layer has the first material composition. The base, first and second sacrificial layers, and first and second diamond layers form a heteroepitaxial super-lattice.

A method of forming a plurality of diamonds provides a base, epitaxially forms a first sacrificial layer on the base, and then epitaxially forms a first diamond layer on the first sacrificial layer. The first sacrificial layer has a first material composition, and the first diamond layer is a material that is different from the first material composition. The method then epitaxially forms a second sacrificial layer on the first diamond layer, and epitaxially forms a second diamond layer on the second sacrificial layer. The second sacrificial layer has the first material composition. The base, first and second sacrificial layers, and first and second diamond layers form a heteroepitaxial super-lattice.

A method for manufacturing substrate-transferred optical coatings, comprising: a) providing a first optical coating on a first host substrate as a base coating structure; b) providing a second optical coating on a second host substrate; c) bonding the optical coating of the base coating structure to the second optical coating, thereby obtaining one combined coating; d) detaching one of the first and the second host substrates from the combined coating; determining if the combined coating fulfills a predetermined condition; e) if the result of the determining step is negative, taking the combined coating together with the remaining host substrate as the base coating structure to be processed next and continuing with step b); f) if the result of the determining step is positive, providing an optical substrate and bonding the optical substrate to the combined coating; g) removing the other one of the first and the second host substrate.