The exemplary embodiments describe techniques for a controlled chemical vapor deposition growth and transfer of arrayed TMD monolayers on predetermined locations, which enable the formation of single crystalline TMD monolayer arrays on specific locations. The unique growth process includes the patterning of transition metal oxide (e.g., MoO.sub.3) on the source substrate contacting the growth substrate face-to-face, where the growth of single crystalline TMD monolayers with controlled size and location, exclusively on predetermined locations on the growth substrates is accomplished. These TMD arrays can be align-transferred using a unique process that combines the wet and stamping transfer processes onto any target substrate with a pin-point accuracy, which dramatically enhances the integrity of transferred TMDs.

A floating catalyst chemical vapor deposition system produces nanotubes. The system includes a reaction chamber, a heater for heating a nanotube-material precursor and a catalyst precursor, and an injector for injecting the precursors into the chamber. In the chamber, the catalyst precursor is pyrolysed to produce catalyst particles, and the nanotube-material precursor is pyrolysed in the presence of the catalyst particles in order to produce nanotubes. A controller controls at least one operational parameter, e.g., injection temperatures of the precursors, flow rates of carrier gases of the precursors, and a reaction temperature of the chamber and of the precursors. An injection pipe extends into the chamber to an adjustable extent in order to control the injection temperature of the catalyst precursor and/or the nanotube-material precursor.

A floating catalyst chemical vapor deposition system produces nanotubes. The system includes a reaction chamber, a heater for heating a nanotube-material precursor and a catalyst precursor, and an injector for injecting the precursors into the chamber. In the chamber, the catalyst precursor is pyrolysed to produce catalyst particles, and the nanotube-material precursor is pyrolysed in the presence of the catalyst particles in order to produce nanotubes. A controller controls at least one operational parameter, e.g., injection temperatures of the precursors, flow rates of carrier gases of the precursors, and a reaction temperature of the chamber and of the precursors. An injection pipe extends into the chamber to an adjustable extent in order to control the injection temperature of the catalyst precursor and/or the nanotube-material precursor.

Disclosed herein are structures comprising a titanium, zirconium, or hafnium powder particle with titanium carbide, zirconium carbide, or hafnium carbide (respectively) nano-whiskers grown directly from and anchored to the powder particle. Also disclosed are methods for fabrication of such structures, involving heating the powder particles and exposing the particles to an organic gas.

Growth of single crystal epitaxial films of the perovskite crystal structure by liquid- or vapor-phase means can be accomplished by providing single-crystal perovskite substrate materials of improved lattice parameter match in the lattice parameter range of interest. Current substrates do not provide as good a lattice match, have inferior properties, or are of limited size and availability because cost of materials and difficulty of growth. This problem is solved by the single-crystal perovskite solid solutions described herein grown from mixtures with an indifferent melting point that occurs at a congruently melting composition at a temperature minimum in the melting curve in the pseudo-binary molar phase diagram. Accordingly, single-crystal perovskite solid solutions, structures, and devices including single-crystal perovskite solid solutions, and methods of making single-crystal perovskite solid solutions are described herein.

Growth of single crystal epitaxial films of the perovskite crystal structure by liquid- or vapor-phase means can be accomplished by providing single-crystal perovskite substrate materials of improved lattice parameter match in the lattice parameter range of interest. Current substrates do not provide as good a lattice match, have inferior properties, or are of limited size and availability because cost of materials and difficulty of growth. This problem is solved by the single-crystal perovskite solid solutions described herein grown from mixtures with an indifferent melting point that occurs at a congruently melting composition at a temperature minimum in the melting curve in the pseudo-binary molar phase diagram. Accordingly, single-crystal perovskite solid solutions, structures, and devices including single-crystal perovskite solid solutions, and methods of making single-crystal perovskite solid solutions are described herein.

A synthetic diamond material comprises a surface, wherein the surface comprises a first surface region comprising a first concentration of quantum spin defects. A second surface region has a predetermined area and is located adjacent to the first surface region, the second region comprising a second concentration of quantum spin defects. The first concentration of quantum spin defects is at least ten times greater than the second concentration of quantum spin defects, and at least one of the first or second surface regions comprises chemical vapour deposition, CVD, synthetic diamond. A method of producing the synthetic diamond material is also disclosed.

A method for solvent-free perovskite deposition. The method comprises loading a lead target and one or more samples adhered to a substrate holder into a deposition chamber, pumping down to a high vacuum pressure, and backfilling the deposition chamber with the vapor of a salt precursor to form a perovskite material.

A gallium nitride substrate comprising a first main surface and a second main surface opposite thereto, wherein the first main surface is a non-polar or semi-polar plane, a dislocation density measured by a room-temperature cathode luminescence method in the first main surface is 110.sup.4 cm.sup.2 or less, and an averaged dislocation density measured by a room-temperature cathode luminescence method in an optional square region sizing 250 m250 m in the first main plan is 110.sup.6 cm.sup.2 or less.

A gallium nitride substrate comprising a first main surface and a second main surface opposite thereto, wherein the first main surface is a non-polar or semi-polar plane, a dislocation density measured by a room-temperature cathode luminescence method in the first main surface is 110.sup.4 cm.sup.2 or less, and an averaged dislocation density measured by a room-temperature cathode luminescence method in an optional square region sizing 250 m250 m in the first main plan is 110.sup.6 cm.sup.2 or less.