Crystals having a modified regular tetrahedron shape are provided. Crystals preferably have four substantially identical triangular faces that define four truncated vertices and six chamfered edges. The six chamfered edges can have an average length of l, and an average width of w, and 8l/w9.5.

Crystals having a modified regular tetrahedron shape are provided. Crystals preferably have four substantially identical triangular faces that define four truncated vertices and six chamfered edges. The six chamfered edges can have an average length of l, and an average width of w, and 8l/w9.5.

The present invention relates to a piezoelectric, epitaxially grown pseudosubstrate comprising a silicon wafer (100) having two parallel faces, and a thin layer of -quartz (100) grown epitaxially on one of the faces of said wafer, said thin -quartz layer (100) exhibiting a uniform crystallization with a mosaicity around the peak (100) of the quartz of between 6 and 1 and a thickness of between 100 nm and 1 m. The present invention also relates to a process for fabricating such a pseudosubstrate, and to the use thereof for producing piezoelectric membranes.

The present invention relates to a piezoelectric, epitaxially grown pseudosubstrate comprising a silicon wafer (100) having two parallel faces, and a thin layer of -quartz (100) grown epitaxially on one of the faces of said wafer, said thin -quartz layer (100) exhibiting a uniform crystallization with a mosaicity around the peak (100) of the quartz of between 6 and 1 and a thickness of between 100 nm and 1 m. The present invention also relates to a process for fabricating such a pseudosubstrate, and to the use thereof for producing piezoelectric membranes.

A method of fabricating at least one single-crystal alloy semiconductor structure, comprising: forming at least one seed on a substrate for growth of at least one single-crystal alloy semiconductor structure, the at least one seed containing an alloying material; providing at least one structural form on the substrate which is crystallized to form the at least one single-crystal alloy semiconductor structure, the at least one structural form being formed of a host material and comprising a main body which extends from the at least one seed and a plurality of elements which are connected in spaced relation to the main body; heating the at least one structural form such that the material of the at least one structural form has a liquid state; and cooling the at least one structural form, such that the material of the at least one structural form nucleates at the least one seed and crystallizes as a single crystal to provide at least one single-crystal alloy semiconductor structure, with a growth front of the single crystal propagating in the main body of the respective structural form away from the respective seed; wherein the plurality of elements of each structural form provide reservoirs of the alloying material in liquid state, such that successive ones of the plurality of elements act to maintain, in liquid state, an available supply of the alloying material to the growth front of the single crystal in the main body of the respective structural form.

A method of fabricating at least one single-crystal alloy semiconductor structure, comprising: forming at least one seed on a substrate for growth of at least one single-crystal alloy semiconductor structure, the at least one seed containing an alloying material; providing at least one structural form on the substrate which is crystallized to form the at least one single-crystal alloy semiconductor structure, the at least one structural form being formed of a host material and comprising a main body which extends from the at least one seed and a plurality of elements which are connected in spaced relation to the main body; heating the at least one structural form such that the material of the at least one structural form has a liquid state; and cooling the at least one structural form, such that the material of the at least one structural form nucleates at the least one seed and crystallizes as a single crystal to provide at least one single-crystal alloy semiconductor structure, with a growth front of the single crystal propagating in the main body of the respective structural form away from the respective seed; wherein the plurality of elements of each structural form provide reservoirs of the alloying material in liquid state, such that successive ones of the plurality of elements act to maintain, in liquid state, an available supply of the alloying material to the growth front of the single crystal in the main body of the respective structural form.

The present disclosure provides a method and apparatus for preparing high-purity crystalline silica particles by mixing colloidal silica with an organic base to form a mixed sol. The mixed sol is heated up to a reaction temperature of about 180 degrees Celsius or above, which is held for a reaction time of about 8 to about 168 hours for a hydrothermal synthesis process in the mixed sol. A gravitational setting or a centrifugation is performed on the mixed sol to provide precipitates from the mixed sol. The precipitates are washed with deionized water to remove residual organic base. The washed precipitates are dried at about 60 to about 80 degrees Celsius and are collected and packaged to obtain high-purity crystalline silica particles.

The present disclosure provides a method and apparatus for preparing high-purity crystalline silica particles by mixing colloidal silica with an organic base to form a mixed sol. The mixed sol is heated up to a reaction temperature of about 180 degrees Celsius or above, which is held for a reaction time of about 8 to about 168 hours for a hydrothermal synthesis process in the mixed sol. A gravitational setting or a centrifugation is performed on the mixed sol to provide precipitates from the mixed sol. The precipitates are washed with deionized water to remove residual organic base. The washed precipitates are dried at about 60 to about 80 degrees Celsius and are collected and packaged to obtain high-purity crystalline silica particles.

The present invention relates to a multilayer material, comprising a solid substrate coated at least partially with a textured -quartz buffer layer, the crystallographic direction of the -quartz being parallel to the crystallographic direction of the silicon; and on said -quartz buffer layer, a layer of one-dimensional epitaxial ZnO microcrystals (or epitaxial ZnO microwires), said microcrystals being self-assembled. The present invention also relates to a method for producing such a multilayer material, as well as to the industrial use thereof in various technical fields.

In a Li.sub.2OAl.sub.2O.sub.3SiO.sub.2 based crystallized glass using SnO.sub.2 as a substitute fining agent for As.sub.2O.sub.3 or Sb.sub.2O.sub.3, a crystallized glass having less yellow coloration is provided at low costs. The glass is a Li.sub.2OAl.sub.2O.sub.3SiO.sub.2 based crystallized glass comprising from 0.01 to 0.9% of SnO.sub.2 in terms of % by mass and having a content of each of As.sub.2O.sub.3 and Sb.sub.2O.sub.3 of 1,000 ppm or less as a glass composition, which has a V.sub.2O.sub.5 content of from 0.08 to 15 ppm in the glass composition.