Methods and wafers for low etch pit density, low slip line density, and low strain indium phosphide are disclosed and may include an indium phosphide single crystal wafer having a diameter of 4 inches or greater, having a measured etch pit density of less than 500 cm.sup.−2, and having fewer than 5 dislocations or slip lines as measured by x-ray diffraction imaging. The wafer may have a measured etch pit density of 200 cm.sup.−2 or less, or 100 cm.sup.−2 or less, or 10 cm.sup.−2 or less. The wafer may have a diameter of 6 inches or greater. An area of the wafer with a measured etch pit density of zero may at least 80% of the total area of the surface. An area of the wafer with a measured etch pit density of zero may be at least 90% of the total area of the surface.

Systems and methods for generating one or more single crystal monolayers from two-dimensional van der Waals crystals are disclosed herein. Example methods include providing a bulk material including a plurality of van der Waals crystal layers, and exfoliating one or more single crystal monolayers of van der Waals crystal from the bulk material by applying a flexible and flat metal tape to a surface of the bulk material. In certain embodiments, the one or more single crystal monolayers can be assembled into an artificial lattice. The present disclosure also provides techniques for manufacturing flexible and flat metal tape for generating one or more single crystal monolayers from two-dimensional van der Waals crystals. The present disclosure also provides compositions for creating a macroscopic artificial lattice. In certain embodiments, the composition can include two or more macroscopic single crystal monolayers adapted from a bulk van der Waals crystal, where the single crystal monolayers are configured for assembly into an artificial lattice based on one or more properties.

A method of manufacturing a hexagonal Group-III nitride semiconductor plate crystal using a crystal cutting wire. where the hexagonal semiconductor crystal has one principal face on one side and another principal face on an opposite side, and the hexagonal semiconductor crystal is cut by causing the crystal cutting wire to move so as to (i) divide the one principal face and the another principal face and (ii) satisfy conditions of Expressions (A) and (B):

25°<α≤90°  Expression (A); and

β=90°±5°  Expression (B) where α represents an angle formed by a c axis of the hexagonal Group-III nitride semiconductor crystal and a normal line of a crystal face cut out by the wire, and β represents an angle formed by a reference axis, which is obtained by perpendicularly projecting the c axis of the hexagonal Group-III nitride semiconductor crystal to the crystal face cut out by the wire, and a cutting direction.

A method of manufacturing a hexagonal Group-III nitride semiconductor plate crystal using a crystal cutting wire. where the hexagonal semiconductor crystal has one principal face on one side and another principal face on an opposite side, and the hexagonal semiconductor crystal is cut by causing the crystal cutting wire to move so as to (i) divide the one principal face and the another principal face and (ii) satisfy conditions of Expressions (A) and (B):

25°<α≤90°  Expression (A); and

β=90°±5°  Expression (B) where α represents an angle formed by a c axis of the hexagonal Group-III nitride semiconductor crystal and a normal line of a crystal face cut out by the wire, and β represents an angle formed by a reference axis, which is obtained by perpendicularly projecting the c axis of the hexagonal Group-III nitride semiconductor crystal to the crystal face cut out by the wire, and a cutting direction.

A synthetic diamond plate comprising a polygonal plate formed of synthetic diamond material, the polygonal plate of synthetic diamond material having a thickness in a range 0.4 mm to 1. mm, and rounded corners having a radius of curvature in a range 1 mm to 6 mm. A mounted synthetic diamond plate is also disclosed comprising a polygonal synthetic diamond plate as described and a base to which the polygonal synthetic diamond plate is bonded, wherein the base comprises a cooling channel. An array of mounted synthetic diamond plates is also described, comprising a plurality of mounted synthetic diamond plates described above, wherein the cooling channels of the mounted synthetic diamond plates are linked to form a common cooling channel across the array of mounted synthetic diamond plates.

A synthetic diamond plate comprising a polygonal plate formed of synthetic diamond material, the polygonal plate of synthetic diamond material having a thickness in a range 0.4 mm to 1. mm, and rounded corners having a radius of curvature in a range 1 mm to 6 mm. A mounted synthetic diamond plate is also disclosed comprising a polygonal synthetic diamond plate as described and a base to which the polygonal synthetic diamond plate is bonded, wherein the base comprises a cooling channel. An array of mounted synthetic diamond plates is also described, comprising a plurality of mounted synthetic diamond plates described above, wherein the cooling channels of the mounted synthetic diamond plates are linked to form a common cooling channel across the array of mounted synthetic diamond plates.

The present disclosure provides advantageous composite films/coatings, and improved methods for fabricating such composite films/coatings. More particularly, the present disclosure provides improved methods for fabricating composite films by trapping at least a portion of a layered material (e.g., hexagonal boron nitride sheets/layers) at an interface of a phase separated system and then introducing the layered material to a polymer film. The present disclosure provides for the use of boron nitride layers to increase the properties (e.g., dielectric constant and breakdown voltage) of polymer films. The exemplary films can be produced by an advantageous climbing technique. Exemplary boron nitride films are composed of overlapping boron nitride sheets with a total thickness of about one nanometer, with the film then transferred onto a polymer film, thereby resulting in significant increases in both dielectric and breakdown properties of the polymer film.

The present disclosure provides advantageous composite films/coatings, and improved methods for fabricating such composite films/coatings. More particularly, the present disclosure provides improved methods for fabricating composite films by trapping at least a portion of a layered material (e.g., hexagonal boron nitride sheets/layers) at an interface of a phase separated system and then introducing the layered material to a polymer film. The present disclosure provides for the use of boron nitride layers to increase the properties (e.g., dielectric constant and breakdown voltage) of polymer films. The exemplary films can be produced by an advantageous climbing technique. Exemplary boron nitride films are composed of overlapping boron nitride sheets with a total thickness of about one nanometer, with the film then transferred onto a polymer film, thereby resulting in significant increases in both dielectric and breakdown properties of the polymer film.

In a case where a detector is positioned in a [11-20] direction, and where a first measurement region including a center of a main surface is irradiated with an X ray in a direction within 15 relative to a [1-120] direction, a ratio of a maximum intensity of a first intensity profile is more than or equal to 1500. In a case where the detector is positioned in a direction parallel to a [1100] direction, and where the first measurement region is irradiated with an X ray in a direction within 6 relative to a [1-100] direction, a ratio of a maximum intensity of a second intensity profile is more than or equal to 1500. An absolute value of a difference between maximum value and minimum value of energy at which the first intensity profile indicates a maximum value is less than or equal to 0.06 keV.

By widening a terrace on a crystal surface on a bottom face of a recess by step flow caused by heating, a flat face is formed on the bottom face of the recess, a two-dimensional material layer made of a two-dimensional material is formed on the formed flat face, and then a device made of the two-dimensional material layer is produced.