Embodiments of this disclosure include apparatus, systems, and methods for fabricating monolayers. In one example, a method includes forming a multilayer film having a plurality of monolayers of a two-dimensional (2D) material on a growth substrate. The multilayer film has a first side proximate the growth substrate and a second side opposite the first side.

Disclosed is a method for manufacturing a monocrystalline semiconductor material of the nitride of a group 13 element, comprising a step of depositing at least one separation layer comprising an element M selected among Ge, Zr, Y, Si, Se, Sc, Mg, In, W, La, Ti, Ta and Hf, by epitaxial growth on a starting substrate; characterised in that an interface layer of formula M.sub.vAl.sub.xO.sub.yN.sub.z is deposited between the starting substrate and the separation layer, wherein: - the atomic indices x and z are greater than 0 and less than or equal to 1; and, - the atomic indices v and y are between 0 and 1; and - the sum y+z is greater than 0.9 and less than or equal to 1.5; and - the sum v+y is greater than or equal to 0.3 and less than or equal to 1.

Disclosed is a method for manufacturing a monocrystalline semiconductor material of the nitride of a group 13 element, comprising a step of depositing at least one separation layer comprising an element M selected among Ge, Zr, Y, Si, Se, Sc, Mg, In, W, La, Ti, Ta and Hf, by epitaxial growth on a starting substrate; characterised in that an interface layer of formula M.sub.vAl.sub.xO.sub.yN.sub.z is deposited between the starting substrate and the separation layer, wherein: - the atomic indices x and z are greater than 0 and less than or equal to 1; and, - the atomic indices v and y are between 0 and 1; and - the sum y+z is greater than 0.9 and less than or equal to 1.5; and - the sum v+y is greater than or equal to 0.3 and less than or equal to 1.

There is provided a nitride crystal substrate comprising group-III nitride crystal and containing n-type impurities, wherein an absorption coefficient α is approximately expressed by equation (1) in a wavelength range of at least 1 μm or more and 3.3 μm or less: α=n Kλ.sup.a (1) (wherein, λ(μm) is a wavelength, α(cm.sup.−1) is absorption coefficient of the nitride crystal substrate at 27° C., n (cm.sup.−3) is a free electron concentration in the nitride crystal substrate, and K and a are constants, satisfying 1.5×10.sup.−19≤K≤6.0×10.sup.−19, a=3).

A method of forming a diamond composite body and the diamond composite body. A first single crystal diamond body is provided, which contains nitrogen and has a uniform strain such that over an area of at least 1×1 mm, at least 90 percent of points display a modulus of strain-induced shift of NV resonance of less than 200 kHz, wherein each point in the area is a resolved region of 50 μm.sup.2. The first single crystal diamond body is treated to convert at least some of the nitrogen to form at least 0.3 ppm nitrogen-vacancy, NV.sup.−, centres. A CVD process is used to grow a second single crystal diamond body on a surface of the first single crystal diamond body. The second single crystal diamond body has an NV concentration less than or equal to 10 times lower than the NV.sup.− concentration in the first single crystal diamond body.

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.

Provided is a α-Ga.sub.2O.sub.3 based semiconductor film which is a semiconductor film in a circular shape having a crystal having a corundum-type crystal structure composed of α-Ga.sub.2O.sub.3 or an α-Ga.sub.2O.sub.3 solid solution as a main phase. The maximum value θ.sub.max and the minimum value θ.sub.min for off-angles at the center point X and four outer circumferential points A, B, C, and D of a surface of the semiconductor film satisfy the relationship of θ.sub.max-θ.sub.min≤0.30°. The off-angle is defined as an inclination angle θ of a crystal axis oriented in the substantially normal direction of the semiconductor film with respect to the film surface normal of the semiconductor film.

A group III-nitride (III-N)-based electronic device includes an engineered substrate, a metalorganic chemical vapor deposition (MOCVD) III-N-based epitaxial layer coupled to the engineered substrate, and a hybrid vapor phase epitaxy (HVPE) III-N-based epitaxial layer coupled to the MOCVD epitaxial layer.

A group III-nitride (III-N)-based electronic device includes an engineered substrate, a metalorganic chemical vapor deposition (MOCVD) III-N-based epitaxial layer coupled to the engineered substrate, and a hybrid vapor phase epitaxy (HVPE) III-N-based epitaxial layer coupled to the MOCVD epitaxial layer.

A method of processing a surface of an epitaxially grown silicon film includes using a radical species to remove random surface terminations from the surface of the epitaxially grown silicon film and to generate a substantially uniform distribution of surface terminations. Reaction systems for performing such a method, and epitaxially grown films prepared using such a method, also are provided.