A silicon carbide epitaxial substrate includes a silicon carbide single crystal substrate and a silicon carbide layer. In a direction parallel to a central region, a ratio of a standard deviation of a carrier concentration of the silicon carbide layer to an average value of the carrier concentration of the silicon carbide layer is less than 5%. The average value of the carrier concentration is more than or equal to 1×10.sup.14 cm.sup.−3 and less than or equal to 5×10.sup.16 cm.sup.−3. In the direction parallel to the central region, a ratio of a standard deviation of a thickness of the silicon carbide layer to an average value of the thickness of the silicon carbide layer is less than 5%. The central region has an arithmetic mean roughness (Sa) of less than or equal to 1 nm. The central region has a haze of less than or equal to 50.

An optoelectronic device includes a flexible substrate, a cerium oxide (CeO.sub.2) layer arranged on the flexible substrate, a single crystal β-III-oxide layer arranged on the CeO.sub.2 layer, and a metallic contact layer arranged on the single crystal β-III-oxide layer.

The present disclosure relates to a method for growing and doping a strained diamond based on a chemical vapor deposition (CVD) method. The method comprises: depositing a gradient buffer layer and a relaxation layer on a substrate layer in sequence by the CVD method; and finally, depositing a CVD strained diamond layer on the relaxation layer and performing doping by the CVD method. According to the method, a lattice constant of the relaxation layer prepared by utilizing the CVD method is greater than a lattice constant of the diamond, so that a diamond generates a stretching strain. In growing and doping processes, the CVD strained diamond is in a stretching strain state. Therefore, a formation energy of a doped element is low, and it is easy to dope the diamond, so that a doping concentration of the diamond is high.

The present invention provides a preparation method of a gallium nitride single crystal based on a ScAlMgO.sub.4 substrate, comprising following steps: (1) providing a ScAlMgO.sub.4 substrate; (2) growing a buffer layer on a surface of the ScAlMgO.sub.4 substrate; (3) annealing the buffer layer; (4) growing a GaN crystal on the buffer layer; (5) performing cooling, so that the GaN crystal is automatically peeled off from the ScAlMgO.sub.4 substrate. The present invention does not need to use a complex MOCVD process for GaN deposition and preprocessing to make a mask or a separation layer, which effectively reduces production costs; compared with traditional substrates such as sapphire, it has higher quality and a larger radius of curvature, and will not cause a problem of OFFCUT non-uniformity for growing GaN over 4 inches; finally, the present invention can realize continuous growth into a crystal bar with a thickness of more than 5 mm, which further reduces the costs.

A method for manufacturing a semiconductor element of the present disclosure includes: a step of preparing a substrate; a first element forming step of forming a first semiconductor layer in a first region on a surface of the substrate; a first element separating step of separating the first semiconductor layer from the substrate; and a second element forming step of forming a second semiconductor layer in a second region on the surface of the substrate from which the first semiconductor layer is separated. Additionally, in the method for manufacturing a semiconductor element of the present disclosure, at least a portion of the second region overlaps the first region.

An electrical device includes an aluminum nitride passivation layer for a mercury cadmium telluride (Hg.sub.1-xCd.sub.xTe) (MCT) semiconductor layer of the device. The AlN passivation layer may be an un-textured amorphous-to-polycrystalline film that is deposited onto the surface of the MCT in its as-grown state, or overlying the MCT after the MCT surface has been pre-treated or partially passivated, in this way fully passivating the MCT. The AlN passivation layer may have a coefficient of thermal expansion (CTE) that closely matches the CTE of the MCT layer, thereby reducing strain at an interface to the MCT. The AlN passivation layer may be formed with a neutral inherent (residual) stress, provide mechanical rigidity, and chemical resistance to protect the MCT.

An epitaxial wafer according to the present disclosure includes: a substrate; a buffer layer formed of a crystal having the composition formula represented by Al.sub.xGa.sub.yIn.sub.zN (x+y+z=1, y>0) on the substrate; a back-barrier layer formed of a crystal having the composition formula represented by Al.sub.xGa.sub.yIn.sub.zN (x+y+z=1, y>0, z>0) on the buffer layer; a channel layer formed of a crystal having the composition formula represented by Al.sub.xGa.sub.yIn.sub.zN (x+y+z=1, y>0) on the back-barrier layer; and an electron-supply layer formed of a crystal having the composition formula represented by Al.sub.xGa.sub.yIn.sub.zN (x+y+z=1, x>0) on the channel layer. The channel layer is constituted with an upper channel layer underneath the electron-supply layer and a lower channel layer on the back-barrier layer, and the lower channel layer has a C concentration higher than the upper channel layer and contains Si.

A process for producing a monocrystalline layer of GaAs material comprises the transfer of a monocrystalline seed layer of SrTiO.sub.3 material to a carrier substrate of silicon material followed by epitaxial growth of a monocrystalline layer of GaAs material.

An epitaxial structure includes a substrate, a nucleation layer on the substrate, a buffer layer on the nucleation layer, and a nitride layer on the buffer layer. The nucleation layer consists of regions in a thickness direction, wherein a chemical composition of the regions is Al.sub.(1-x)In.sub.xN, where 0≤x≤1. A maximum value of the x value in the plurality of regions is the same, a minimum value of the x value in the plurality of regions is the same, and an absolute value of a gradient slope of each of the regions is 0.1%/nm to 50%/nm. A thickness of the nucleation layer is less than a thickness of the buffer layer. A roughness of a surface of the nucleation layer in contact with the buffer layer is greater than a roughness of a surface of the buffer layer in contact with the nitride layer.

A single crystal multilayer low-loss optical component including first and second layers made from dissimilar materials, with the materials including the first layer lattice-matched to the materials including the second layer. The first and second layers are grown epitaxially in pairs on a growth substrate to which the materials of the first layer are also lattice-matched, such that a single crystal multilayer optical component is formed. The optical component may further include a second substrate to which the layer pairs are wafer bonded after being removed from the growth substrate.