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 method of fabricating one or more colour centres in a crystal is described. The method comprises focusing a laser into a crystal to induce the creation, modification, or diffusion of defects within a focal region of the laser. Fluorescence detection is used to determine when one or more colour centres are formed within the focal region and the laser is terminated when a desired number of colour centres have been formed. The method enables colour centres to be formed in a crystal with a high degree of control in terms of both the number and location of colour centres within the crystal, and a degree of control over other parameters such as colour centre orientation and local environment. In particular, it is possible to form a well-defined pattern of colour centres within a crystal.

A method of fabricating one or more colour centres in a crystal is described. The method comprises focusing a laser into a crystal to induce the creation, modification, or diffusion of defects within a focal region of the laser. Fluorescence detection is used to determine when one or more colour centres are formed within the focal region and the laser is terminated when a desired number of colour centres have been formed. The method enables colour centres to be formed in a crystal with a high degree of control in terms of both the number and location of colour centres within the crystal, and a degree of control over other parameters such as colour centre orientation and local environment. In particular, it is possible to form a well-defined pattern of colour centres within a crystal.

A silicon carbide substrate has a first main surface, a second main surface, and a chamfered portion. The second main surface is opposite to the first main surface. The chamfered portion is contiguous to each of the first main surface and the second main surface. The silicon carbide substrate has a maximum diameter of 150 mm or more. A surface manganese concentration in the chamfered portion is 1×10.sup.11 atoms/cm.sup.2 or less.

A silicon carbide substrate has a first main surface, a second main surface, and a chamfered portion. The second main surface is opposite to the first main surface. The chamfered portion is contiguous to each of the first main surface and the second main surface. The silicon carbide substrate has a maximum diameter of 150 mm or more. A surface manganese concentration in the chamfered portion is 1×10.sup.11 atoms/cm.sup.2 or less.

A method for processing a lithium tantalate crystal substrate includes providing a lithium tantalate crystal substrate, roughening the lithium tantalate crystal substrate, providing a catalytic agent, bringing the lithium tantalate crystal substrate and the catalytic agent into contact with each other after the lithium tantalate crystal substrate is roughened, and subjecting the lithium tantalate crystal substrate to a reduction treatment. The reduction treatment is conducted at a temperature not higher than a Curie temperature of the lithium tantalate crystal substrate. The catalytic agent is selected from the group consisting of metal powder, metal gas, and metal carbonate powder.

Single crystal CVD diamond material comprising a total nitrogen concentration of at least 5 ppm and a neutral single substitutional nitrogen. N.sub.s.sup.0, to total single substitutional nitrogen, N.sub.s, ratio of at least 0.7. Such a diamond is observed to have a relatively low amount of brown colouration despite the relatively high concentration of nitrogen A method of making the single crystal diamond is also disclosed, the method including growing the CVD diamond in process gases comprising 60 to 200 ppm nitrogen, in addition to a carbon-containing gas, and hydrogen, wherein the ratio of carbon atoms in the carbon-containing gas to hydrogen atoms in the hydrogen gas is 0.5 to 1.5%.

A nitride semiconductor substrate that is constituted by a single crystal of a group III nitride semiconductor and includes a main surface for which the closest low index crystal plane is a (0001) plane includes an inclined interface growth region that has grown with inclined interfaces other than the (0001) plane serving as growth surfaces. A ratio of an area occupied by the inclined interface growth region in the main surface is 80% or more. When a dislocation density is determined based on a dark spot density by observing the main surface in a field of view that is 250 μm square using a multiphoton excitation microscope, the main surface does not include a region that has a dislocation density higher than 3×10.sup.6 cm.sup.−2, and the main surface includes dislocation-free regions that are 50 μm square and do not overlap each other, at a density of 100 regions/cm.sup.2 or more.

A nitride semiconductor substrate that is constituted by a single crystal of a group III nitride semiconductor and includes a main surface for which the closest low index crystal plane is a (0001) plane includes an inclined interface growth region that has grown with inclined interfaces other than the (0001) plane serving as growth surfaces. A ratio of an area occupied by the inclined interface growth region in the main surface is 80% or more. When a dislocation density is determined based on a dark spot density by observing the main surface in a field of view that is 250 μm square using a multiphoton excitation microscope, the main surface does not include a region that has a dislocation density higher than 3×10.sup.6 cm.sup.−2, and the main surface includes dislocation-free regions that are 50 μm square and do not overlap each other, at a density of 100 regions/cm.sup.2 or more.