One variation of a method includes: ingesting an air sample captured during an air capture period at a target location for collection of a first mixture including carbon dioxide and a first concentration of impurities; conveying the first mixture through a liquefaction unit to generate a second mixture including carbon dioxide and a second concentration of impurities less than the first concentration of impurities; in a methanation reactor, mixing the second mixture with hydrogen to generate a first hydrocarbon mixture comprising a third concentration of impurities comprising nitrogen, carbon dioxide, and hydrogen; conveying the first hydrocarbon mixture through a separation unit configured to remove impurities from the first hydrocarbon mixture to generate a second hydrocarbon a fourth concentration of impurities less than the third concentration of impurities; and depositing the second hydrocarbon mixture in a diamond reactor containing a set of diamond seeds to generate a first set of diamonds.

A synthetic single crystal diamond containing 100 ppm or more and 1500 ppm or less of nitrogen atoms, in which the synthetic single crystal diamond contains aggregates each composed of one vacancy and two to four nitrogen atoms present adjacent to the vacancy, a ratio b/a of a length b of a short diagonal line to a length a of a long diagonal line of diagonal lines of a Knoop indentation in a <110> direction in a {001} plane of the synthetic single crystal diamond is 0.08 or less, and the Knoop indentation is formed by measuring Knoop hardness in the <100> direction in the {001} plane of the synthetic single crystal diamond according to JIS Z 2251: 2009 under conditions of a temperature of 23° C.±5° C. and a test load of 4.9 N.

A synthetic single crystal diamond containing nitrogen atoms at a concentration of 100 ppm or more and 1500 ppm or less based on atom numbers, in which the synthetic single crystal diamond contains aggregates each composed of one vacancy and three substitutional nitrogen atoms present adjacent to the vacancy, and a Raman shift λ′ cm.sup.−1 of a peak in a first-order Raman scattering spectrum of the synthetic single crystal diamond and a Raman shift λ cm.sup.−1 of a peak in a first-order Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a concentration of 1 ppm or less based on atom numbers show a relationship of the following formula 1,

λ′−λ≥0  Formula 1.

A synthetic single crystal diamond containing nitrogen atoms at a concentration of 100 ppm or more and 1500 ppm or less based on atom numbers, in which the synthetic single crystal diamond contains aggregates each composed of one vacancy and three substitutional nitrogen atoms present adjacent to the vacancy, and a Raman shift λ′ cm.sup.−1 of a peak in a first-order Raman scattering spectrum of the synthetic single crystal diamond and a Raman shift λ cm.sup.−1 of a peak in a first-order Raman scattering spectrum of a synthetic type IIa single crystal diamond containing nitrogen atoms at a concentration of 1 ppm or less based on atom numbers show a relationship of the following formula 1,

λ′−λ≥0  Formula 1.

The present invention relates to a method for manufacturing a diamond substrate, and more particularly, to a method of growing diamond after forming a structure of an air gap having a crystal correlation with a lower substrate by heat treatment of a photoresist pattern and an air gap forming film material on a substrate such as sapphire (Al.sub.2O.sub.3). Through such a method, a process is simplified and the cost is lowered when large-area/large-diameter single crystal diamond is heterogeneously grown, stress due to differences in a lattice constant and a coefficient of thermal expansion between the heterogeneous substrate and diamond is relieved, and an occurrence of defects or cracks is reduced even when a temperature drops, such that a high-quality single crystal diamond substrate may be manufactured and the diamond substrate may be easily self-separated from the heterogeneous substrate.

Methods for producing layered nanocarbon structures placing a workpiece in a working chamber, applying a vacuum to the chamber, processing the workpiece surface with gas ions, applying a material sublayer to the workpiece surface, depositing carbon ions from a carbon plasma on the workpiece surface to apply an amorphous diamond-like sp3 carbon coating layer on the workpiece surface. The methods include irradiating the growing carbon coating with accelerated ions of an inert gas at a first energy range to apply a graphite sp2 carbon coating layer on the sp3 carbon coating layer and irradiating the growing carbon coating with accelerated ions of the inert gas at a second energy range, different from the first energy range, to apply a linear chain and polymer sp1 carbon coating layer on the sp2 carbon coating layer.

Methods for producing layered nanocarbon structures placing a workpiece in a working chamber, applying a vacuum to the chamber, processing the workpiece surface with gas ions, applying a material sublayer to the workpiece surface, depositing carbon ions from a carbon plasma on the workpiece surface to apply an amorphous diamond-like sp3 carbon coating layer on the workpiece surface. The methods include irradiating the growing carbon coating with accelerated ions of an inert gas at a first energy range to apply a graphite sp2 carbon coating layer on the sp3 carbon coating layer and irradiating the growing carbon coating with accelerated ions of the inert gas at a second energy range, different from the first energy range, to apply a linear chain and polymer sp1 carbon coating layer on the sp2 carbon coating layer.

Disclosed herein are synthetic, or cultured diamonds which have at least one artificially embedded inclusion(s) incorporated within their crystal structure during the diamond's deposition or growth process. Disclosed are cultured diamonds having a substrate portion, artificially embedded inclusion(s) disposed on the substrate portion, and an encapsulating portion, formed on the artificially embedded inclusion(s). The substrate portion and the encapsulating portion are bonded together by covalent carbon to carbon bonds.

Disclosed herein are synthetic, or cultured diamonds which have at least one artificially embedded inclusion(s) incorporated within their crystal structure during the diamond's deposition or growth process. Disclosed are cultured diamonds having a substrate portion, artificially embedded inclusion(s) disposed on the substrate portion, and an encapsulating portion, formed on the artificially embedded inclusion(s). The substrate portion and the encapsulating portion are bonded together by covalent carbon to carbon bonds.

A method of manufacturing a diamond substrate includes: forming an ion implantation layer at a side of a main surface of a diamond seed substrate by implanting ions into the main surface of the diamond seed substrate; producing a diamond structure by growing a diamond growth layer by a vapor phase synthesis method on the main surface of the diamond seed substrate, after implanting the ions; and performing heat treatment on the diamond structure. The performed heat treatment causes the diamond structure to be separated along the ion implantation layer into a first structure including the diamond seed substrate and failing to include the diamond growth layer, and a diamond substrate including the diamond growth layer. Thus, the method of manufacturing a diamond substrate is provided that enables a diamond substrate with a large area to be manufactured in a short time and at a low cost.