GaAs IR window slabs having largest dimensions that are greater than 8 inches, and preferably greater than 12 inches, are grown using the Horizontal Gradient Freeze (HGF) method. Heat extraction is simplified by using a shallow horizontal boat that is only slightly deeper than the desired window thickness, thereby enabling growth of large slabs while also minimizing material waste and fabrication cost as compared to slicing and shaping thick plates from large, melt-grown boules. Single crystal seeds can be used to optimize the final orientation of the slabs and minimize secondary nucleation, thereby maximizing yield. A conductive doped GaAs layer can be applied to the IR window slab to provide EMI shielding. The temperature gradient during HGF can be between 1? C./cm and 3? C./cm, and the directional solidification can be at a rate of between 0.25 mm/h and 2.5 mm/h.

A compound of cesium fluorooxoborate, a nonlinear optical crystal of cesium fluorooxoborate, and a method of preparation and use thereof. The compound has a chemical formula of CsB.sub.4O.sub.6F and a molecular weight of 291.15. It has a crystal structure, which is prepared by a solid-state synthesis method or a vacuum encapsulation method. The crystal has a chemical formula of CsB.sub.4O.sub.6F and a molecular weight of 291.15. It belongs to an orthorhombic crystal system, with a space group of Pna2.sub.1, crystal cell parameters of a=7.9241 , b=11.3996 , c=6.6638 , and ===90, and a unit cell volume of 601.95 .sup.3. A melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method is used to grow the crystal of CsB.sub.4O.sub.6F.

A compound of cesium fluorooxoborate, a nonlinear optical crystal of cesium fluorooxoborate, and a method of preparation and use thereof. The compound has a chemical formula of CsB.sub.4O.sub.6F and a molecular weight of 291.15. It has a crystal structure, which is prepared by a solid-state synthesis method or a vacuum encapsulation method. The crystal has a chemical formula of CsB.sub.4O.sub.6F and a molecular weight of 291.15. It belongs to an orthorhombic crystal system, with a space group of Pna2.sub.1, crystal cell parameters of a=7.9241 , b=11.3996 , c=6.6638 , and ===90, and a unit cell volume of 601.95 .sup.3. A melt method, high temperature solution method, vacuum encapsulation method, hydrothermal method or room temperature solution method is used to grow the crystal of CsB.sub.4O.sub.6F.

Disclosed is a nonlinear optical (NLO) material for use in deep-UV applications, and methods of fabrication thereof. The NLO is fabricated from a plurality of components according to the formula A.sub.qB.sub.yC.sub.z and a crystallographic non-centrosymmetric (NCS) structure. The NLO material may be fabricated as a polycrystalline or a single crystal material. In an embodiment, the material may be according to a formula Ba.sub.3ZnB.sub.5PO.sub.14.

Disclosed is a nonlinear optical (NLO) material for use in deep-UV applications, and methods of fabrication thereof. The NLO is fabricated from a plurality of components according to the formula A.sub.qB.sub.yC.sub.z and a crystallographic non-centrosymmetric (NCS) structure. The NLO material may be fabricated as a polycrystalline or a single crystal material. In an embodiment, the material may be according to a formula Ba.sub.3ZnB.sub.5PO.sub.14.

A silicon carbide crystal and a manufacturing method for same are provided. A silicon carbide crystal seed used for the silicon carbide crystal has a crystal-growing surface with a surface roughness (Ra) less than 2.0 nm, and a thickness of the silicon carbide crystal seed is less than 700 m. Therefore, the silicon carbide crystal grown from the silicon carbide crystal seed by sublimation method (which is also a PVT method) may have low basal plane dislocation (BPD) and low micropipe density (MPD).

A silicon carbide crystal and a manufacturing method for same are provided. A silicon carbide crystal seed used for the silicon carbide crystal has a crystal-growing surface with a surface roughness (Ra) less than 2.0 nm, and a thickness of the silicon carbide crystal seed is less than 700 m. Therefore, the silicon carbide crystal grown from the silicon carbide crystal seed by sublimation method (which is also a PVT method) may have low basal plane dislocation (BPD) and low micropipe density (MPD).

Produced is a large single crystal with no crystal grain boundary, which is a high-quality single crystal that has a uniform composition in both the vertical and horizontal directions at an optimum dopant concentration and contains only a small number of negative crystals and exsolution lamellae. A single-crystal production equipment includes at least: a quartz crucible in which a seed crystal is placed on its bottom; a powder raw material supply apparatus which supplies a powder raw material into the quartz crucible; and an infrared ray irradiation apparatus which applies an infrared ray to the powder raw material supplied into the quartz crucible from the powder raw material supply apparatus.

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.