Large area seed crystals for ammonothermal GaN growth are fabricated by deposition or layer transfer of a GaN layer on a CTE-matched handle substrate. The sides and back of the handle substrate are protected from the ammonothermal growth environment by a coating comprising an adhesion layer, a diffusion barrier layer, and an inert layer. A patterned mask, also comprising an adhesion layer, a diffusion barrier layer, and an inert layer, may be provided over the GaN layer to allow for reduction of the dislocation density by lateral epitaxial growth.

Provided is a self-supporting polycrystalline GaN substrate composed of GaN-based single crystal grains having a specific crystal orientation in a direction approximately normal to the substrate. The crystal orientations of individual GaN-based single crystal grains as determined from inverse pole figure mapping by EBSD analysis on the substrate surface are distributed with tilt angles from the specific crystal orientation, the average tilt angle being 1 to 10. There is also provided a light emitting device including the self-supporting substrate and a light emitting functional layer, which has at least one layer composed of semiconductor single crystal grains, the at least one layer having a single crystal structure in the direction approximately normal to the substrate. The present invention makes it possible to provide a self-supporting polycrystalline GaN substrate having a reduced defect density at the substrate surface, and to provide a light emitting device having a high luminous efficiency.

The present disclosure relates to methods for upcycling of spent lithium-ion battery cathodes. In some embodiments, the methods may include admixing delithiated NCM particles with a supplementary lithium source comprising a single lithium salt to produce single-crystal NCM particles with effective size control and improved electrochemical performance compared to pristine polycrystalline NCM.

The present disclosure relates to methods for upcycling of spent lithium-ion battery cathodes. In some embodiments, the methods may include admixing delithiated NCM particles with a supplementary lithium source comprising a single lithium salt to produce single-crystal NCM particles with effective size control and improved electrochemical performance compared to pristine polycrystalline NCM.

The invention provides a process for the production of crystalline titanium powder containing single crystals or agglomerates of single crystals having an average crystal size (by volume) greater than 1 m, said process including reacting a titanium chloride species, preferably titanium dichloride, and reducing metal in a continuous back-mix reactor to produce a free flowing suspension of titanium powder in molten chloride salt wherein: i. both the titanium chloride species and the reducing metal are dissolved in a molten chloride salt and fed to the reactor containing a chloride salt of the reducing metal; ii. the average feed ratio of the titanium chloride species and reducing metal to the continuous back-mix reactor is within 1%, preferably within 0.1%, of the stoichiometric ratio required to fully reduce the titanium chloride salt to titanium metal; iii. the concentration of titanium powder in the fluid suspension of titanium powder in molten salt in the continuous back-mix reactor is between 2 and 23 mass %; and iv. The reducing metal is lithium, sodium, magnesium, or calcium.

The invention provides a process for the production of crystalline titanium powder containing single crystals or agglomerates of single crystals having an average crystal size (by volume) greater than 1 m, said process including reacting a titanium chloride species, preferably titanium dichloride, and reducing metal in a continuous back-mix reactor to produce a free flowing suspension of titanium powder in molten chloride salt wherein: i. both the titanium chloride species and the reducing metal are dissolved in a molten chloride salt and fed to the reactor containing a chloride salt of the reducing metal; ii. the average feed ratio of the titanium chloride species and reducing metal to the continuous back-mix reactor is within 1%, preferably within 0.1%, of the stoichiometric ratio required to fully reduce the titanium chloride salt to titanium metal; iii. the concentration of titanium powder in the fluid suspension of titanium powder in molten salt in the continuous back-mix reactor is between 2 and 23 mass %; and iv. The reducing metal is lithium, sodium, magnesium, or calcium.

We provide methods and apparatus for preparing crystalline-clad and crystalline core optical fibers with minimal or no breakage by minimizing the influence of thermal stress during a liquid phase epitaxy (LPE) process as well as the fiber with precisely controlled number of modes propagated in the crystalline cladding and crystalline core fiber via precisely controlling the diameter of crystalline fiber core with under-saturated LPE flux. The resulting crystalline cladding and crystalline core optical fibers are also reported.

We provide methods and apparatus for preparing crystalline-clad and crystalline core optical fibers with minimal or no breakage by minimizing the influence of thermal stress during a liquid phase epitaxy (LPE) process as well as the fiber with precisely controlled number of modes propagated in the crystalline cladding and crystalline core fiber via precisely controlling the diameter of crystalline fiber core with under-saturated LPE flux. The resulting crystalline cladding and crystalline core optical fibers are also reported.

A CVD single crystal diamond material suitable for use in, or as, an optical device or element. It is suitable for use in a wide range of optical applications such as, for example, optical windows, laser windows, optical reflectors, optical refractors and gratings, and etalons. The CVD diamond material is produced by a CVD method in the presence of a controlled low level of nitrogen to control the development of crystal defects and thus achieve a diamond material having key characteristics for optical applications.

Provided is a self-supporting gallium nitride substrate useful as an alternative material for a gallium nitride single crystal substrate, which is inexpensive and also suitable for having a large area. This substrate is composed of a plate composed of gallium nitride-based single crystal grains, wherein the plate has a single crystal structure in the approximately normal direction. This substrate can be manufactured by a method comprising providing an oriented polycrystalline sintered body; forming a seed crystal layer composed of gallium nitride on the sintered body so that the seed crystal layer has crystal orientation mostly in conformity with the crystal orientation of the sintered body; forming a layer with a thickness of 20 m or greater composed of gallium nitride-based crystals on the seed crystal layer so that the layer has crystal orientation mostly in conformity with crystal orientation of the seed crystal layer; and removing the sintered body.