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.

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 method for producing high-purity SiC single crystal, which is applicable to a process of growing SiC single crystal through a solution growth method. This method is for producing SiC single crystal and includes growing, through a solution growth method, an epitaxial layer on a seed material, at least a surface of which is made of SiC, wherein the SiC single crystal is grown so that impurity concentrations therein measured by secondary ion mass spectrometry are very small. Also provided is a housing container for growing SiC single crystal through a solution growth method using a Si melt, including a feed material that is disposed on at least a surface of the housing container and adds, to the Si melt, an additional material that is SiC and/or C. Performing the solution growth method using this housing container can produce high-purity SiC single crystal without any special treatment.

Provided is a method for producing high-purity SiC single crystal, which is applicable to a process of growing SiC single crystal through a solution growth method. This method is for producing SiC single crystal and includes growing, through a solution growth method, an epitaxial layer on a seed material, at least a surface of which is made of SiC, wherein the SiC single crystal is grown so that impurity concentrations therein measured by secondary ion mass spectrometry are very small. Also provided is a housing container for growing SiC single crystal through a solution growth method using a Si melt, including a feed material that is disposed on at least a surface of the housing container and adds, to the Si melt, an additional material that is SiC and/or C. Performing the solution growth method using this housing container can produce high-purity SiC single crystal without any special treatment.

The purpose of diffusion assisted crystal hydrothermal growth is to facilitate a greatly increased crystal growth rate that would save time that is precious in such a material and manpower costly process. The assisted crystal growth itself requires the utilization of a piezoelectric shaker connected to the autoclave in which most industrial hydrothermal crystals are grown. The waveform can be modulated to induce transport of nutrient in a singular direction, customized to the topology of the apparatus. As it stands currently, the growth of most crystals that require autoclaves for their production can take anywhere from 3 months to up to 2 years, and accordingly carries many costs, particularly electricity and supervision of the autoclave(s), and other issues that may arise during the growth. While the product of this labor results in high-quality crystals, in reality, these are not at all what is needed outside of the laboratory environment. Using the assisted crystal hydrothermal growth process, average crystal growth can be cut in half, with the resulting crystals consequently being of a slightly lower quality, though still sufficient for most engineering purposes. Another advantage of using a piezoelectric shaker is that an additional sensor can be added to the autoclave to monitor the health of the autoclave using trending data obtained during the growth.

The purpose of diffusion assisted crystal hydrothermal growth is to facilitate a greatly increased crystal growth rate that would save time that is precious in such a material and manpower costly process. The assisted crystal growth itself requires the utilization of a piezoelectric shaker connected to the autoclave in which most industrial hydrothermal crystals are grown. The waveform can be modulated to induce transport of nutrient in a singular direction, customized to the topology of the apparatus. As it stands currently, the growth of most crystals that require autoclaves for their production can take anywhere from 3 months to up to 2 years, and accordingly carries many costs, particularly electricity and supervision of the autoclave(s), and other issues that may arise during the growth. While the product of this labor results in high-quality crystals, in reality, these are not at all what is needed outside of the laboratory environment. Using the assisted crystal hydrothermal growth process, average crystal growth can be cut in half, with the resulting crystals consequently being of a slightly lower quality, though still sufficient for most engineering purposes. Another advantage of using a piezoelectric shaker is that an additional sensor can be added to the autoclave to monitor the health of the autoclave using trending data obtained during the growth.

A crystalline silicon ingot and a method of fabricating the same are disclosed. The crystalline silicon ingot of the invention includes multiple silicon crystal grains growing in a vertical direction of the crystalline silicon ingot. The crystalline silicon ingot has a bottom with a silicon crystal grain having a first average crystal grain size of less than about 12 mm. The crystalline silicon ingot has an upper portion, which is about 250 mm away from said bottom, with a silicon crystal grain having a second average crystal grain size of greater than about 14 mm.

A crystal growth apparatus includes a pressure-resistant vessel; a plurality of support tables arranged inside the pressure-resistant vessel; inner vessels each placed over the support tables, respectively; growth vessels contained the inner vessels, respectively; a heating means for heating the growth vessels; and a central rotating shaft connected to the support tables. The central rotating shaft is distant from central axes of the inner vessels, respectively. A seed crystal, a raw material of the Group 13 element and a flux are charged in each of the growth vessels, and the growth vessels are heated to form a melt and a nitrogen-containing gas is supplied to the melt to grow a crystal of a nitride of said Group 13 element while the central rotating shaft is rotated.