Embodiments described herein relate generally to the large scale production of functionalized graphene. In some embodiments, a method for producing functionalized graphene includes combining a crystalline graphite with a first electrolyte solution that includes at least one of a metal hydroxide salt, an oxidizer, and a surfactant. The crystalline graphite is then milled in the presence of the first electrolyte solution for a first time period to produce a thinned intermediate material. The thinned intermediate material is combined with a second electrolyte solution that includes a strong oxidizer and at least one of a metal hydroxide salt, a weak oxidizer, and a surfactant. The thinned intermediate material is then milled in the presence of the second electrolyte solution for a second time period to produce functionalized graphene.

Embodiments described herein relate generally to the large scale production of functionalized graphene. In some embodiments, a method for producing functionalized graphene includes combining a crystalline graphite with a first electrolyte solution that includes at least one of a metal hydroxide salt, an oxidizer, and a surfactant. The crystalline graphite is then milled in the presence of the first electrolyte solution for a first time period to produce a thinned intermediate material. The thinned intermediate material is combined with a second electrolyte solution that includes a strong oxidizer and at least one of a metal hydroxide salt, a weak oxidizer, and a surfactant. The thinned intermediate material is then milled in the presence of the second electrolyte solution for a second time period to produce functionalized graphene.

A composite substrate (100) for a photonic crystal element includes: an electro-optical crystal substrate (10) having an electro-optical effect; an optical loss-suppressing and cavity-processing layer (20) arranged on one surface of the electro-optical crystal substrate (10); and a support substrate (30) integrated with the electro-optical crystal substrate (10) through the optical loss-suppressing and cavity-processing layer (20).

A method for manufacturing epitaxial films with multiple stress states, comprising steps of: providing a first single crystal substrate, and forming a sacrificial layer and a first epitaxial film on the first single crystal substrate, wherein the first epitaxial film is made of a first material;

removing the sacrificial layer to separate the first epitaxial film from the first single crystal substrate; transferring the first epitaxial film to a second single crystal substrate, wherein the second single crystal substrate is made of a second material, a partial surface of the second single crystal substrate being overlapped by the first epitaxial film; applying epitaxies onto the first epitaxial film and the second single crystal substrate to form a second epitaxial film on the first epitaxial film and the second single crystal substrate.

High quality ammonothermal group III metal nitride crystals having a pattern of locally-approximately-linear arrays of threading dislocations, methods of manufacturing high quality ammonothermal group III metal nitride crystals, and methods of using such crystals are disclosed. The crystals are useful for seed bulk crystal growth and as substrates for light emitting diodes, laser diodes, transistors, photodetectors, solar cells, and for photoelectrochemical water splitting for hydrogen generation devices.

A composite substrate capable of improving temperature characteristics while suppressing crack generation and a method for manufacturing such composite substrate is provided. The method for manufacturing composite substrates includes: a step of preparing a piezoelectric material substrate having a rough surface; a step of removing the damaged layer by etching the rough surface of the piezoelectric material substrate using a chemical process; a step of depositing an intervening layer on the rough surface of the piezoelectric material substrate from which the damaged layer has been removed; a step of flattening the surface of the deposited intervening layer; a step of bonding the piezoelectric material substrate to a support substrate having a lower thermal expansion coefficient than the piezoelectric material, with the deposited intervening layer in between; and a step of thinning the piezoelectric material substrate after bonding. Lithium tantalate (LT) or lithium niobate (LN) are suitable as the piezoelectric material.

A method of producing a wafer from a hexagonal single-crystal ingot includes the steps of planarizing an end face of the hexagonal single-crystal ingot, forming a peel-off layer in the hexagonal single-crystal ingot by applying a pulsed laser beam whose wavelength is transmittable through the hexagonal single-crystal ingot while positioning a focal point of the pulsed laser beam in the hexagonal single-crystal ingot at a depth corresponding to a thickness of a wafer to be produced from the planarized end face of the hexagonal single-crystal ingot, recording a fabrication history on the planarized end face of the hexagonal single-crystal ingot by applying a pulsed laser beam to the hexagonal single-crystal ingot while positioning a focal point of the last-mentioned pulsed laser beam in a device-free area of the wafer to be produced.

A method for forming a laterally-grown group III metal nitride crystal includes providing a substrate, the substrate including one of sapphire, silicon carbide, gallium arsenide, silicon, germanium, a silicon-germanium alloy, MgAl.sub.2O.sub.4 spinel, ZnO, ZrB.sub.2, BP, InP, AlON, ScAlMgO.sub.4, YFeZnO.sub.4, MgO, Fe.sub.2NiO.sub.4, LiGa.sub.5O.sub.8, Na.sub.2MoO.sub.4, Na.sub.2WO.sub.4, In.sub.2CdO.sub.4, lithium aluminate (LiAlO.sub.2), LiGaO.sub.2, Ca.sub.8La.sub.2(PO.sub.4).sub.6O.sub.2, gallium nitride, or aluminum nitride (AlN), forming a pattern on the substrate, the pattern comprising growth centers having a minimum dimension between 1 micrometer and 100 micrometers, and being characterized by at least one pitch dimension between 20 micrometers and 5 millimeters, growing a group III metal nitride from the pattern of growth centers vertically and laterally, and removing the laterally-grown group III metal nitride layer from the substrate. A laterally-grown group III metal nitride layer coalesces, leaving an air gap between the laterally-grown group III metal nitride layer and the substrate or a mask thereupon.

A method for method for manufacturing a rutile titanium dioxide layer according to the inventive concept includes forming a sacrificial layer on a substrate, and depositing a titanium dioxide (TiO.sub.2) material on the sacrificial layer. The sacrificial layer includes a metal oxide of a rutile phase. An amount of oxygen vacancy of the sacrificial layer after depositing the titanium dioxide material is greater than an amount of oxygen vacancy of the sacrificial layer before depositing the titanium dioxide material. The metal oxide includes a metal different from titanium (Ti).

The present invention attempts to solve the problem of providing novel technology that makes it possible to grow high-quality semiconductor substrates. In order to solve the abovementioned problem, the present invention provides: a method for producing semiconductor substrates that includes an installation step in which starting substrates and starting materials are installed in an alternating manner and a heating step in which the starting substrates and the starting materials are heated and a growth layer is formed on the starting substrates; and a device for producing the semiconductor substrates. Owing to this configuration, the present invention makes it possible to simultaneously achieve desired growth conditions in each of a plurality of starting substrates and thereby provide novel technology that makes it possible to grow high-quality semiconductor substrates.