Bulk single crystal of aluminum nitride (AlN) having an areal planar defect density≦100 cm.sup.−2. Methods for growing single crystal aluminum nitride include melting an aluminum foil to uniformly wet a foundation with a layer of aluminum, the foundation forming a portion of an AlN seed holder, for an AlN seed to be used for the AlN growth. The holder may consist essentially of a substantially impervious backing plate.

A Group III nitride substrate contains a base material part of a Group III nitride having a front surface and a back surface, the front surface of the base material part and the back surface of the base material part having different Mg concentrations from each other.

A silicon carbide powder which, when used as a raw material in a sublimation recrystallization method, enables improvement in productivity of a silicon carbide single crystal by exhibiting a high sublimation rate and allowing a small amount of silicon carbide to remain without being sublimated, and enables an increase in size of the silicon carbide single crystal (for example, a single crystal wafer). The silicon carbide powder has a Blaine specific surface area of from 250 cm.sup.2/g to 1,000 cm.sup.2/g and a ratio of a silicon carbide powder having a particle size of more than 0.70 mm and 3.00 mm or less of 50 vol % or more with respect to a total amount of the silicon carbide powder. When a silicon carbide powder accommodated in a crucible is heated to be sublimated, a silicon carbide single crystal is formed on a seed crystal provided on an undersurface of a lid.

There is provided a method for manufacturing a nitride semiconductor template, including the steps of: growing and forming a buffer layer in a thickness of not more than a peak width of a projection and in a thickness of not less than 10 nm and not more than 330 nm on a sapphire substrate formed by arranging conical or pyramidal projections on its surface in a lattice pattern; and growing and forming a nitride semiconductor layer on the buffer layer.

A ferroelectric device comprising a substrate; a textured layer; a first electrode comprising a thin layer of metallic material having a crystal lattice structure divided into granular regions; a seed layer; the seed layer being epitaxially deposited so as to form a column-like structure on top of the granular regions of the first electrode; at least one ferroelectric material layer exhibiting spontaneous polarization epitaxially deposited on the seed layer; the ferroelectric material layer, the seed layer, and first electrode each having granular regions in which column-like structures produce a high degree of polarization normal to the growth plane and a method of making.

There is provided a method for manufacturing a nitride semiconductor template, including the steps of: growing and forming a buffer layer to be thicker than a peak width of a projection and in a thickness of not less than 11 nm and not more than 400 nm on a sapphire substrate formed by arranging conical or pyramidal projections on its surface in a lattice pattern; and growing and forming a nitride semiconductor layer on the buffer layer.

An ultra-hard carbon film is formed by the uniaxial compression of thin films of graphene. The graphene films are two or three layers thick (2-L or 3-L). High pressure compression forms a diamond-like film and provides improved properties to the coated substrates.

An electro-optical waveguide modulator device includes a seed layer on a substrate, the seed layer having a first crystallographic plane aligned with a surface of the seed layer, an electro-optical channel extending in a first direction on the seed layer and having a second crystallographic plane aligned with the surface of the seed layer, an insulator layer on both sides of the electro-optical channel on the substrate in a second direction perpendicular to the first direction, an electrode barrier layer on the electro-optical channel and the insulator layer, and one or more of electrodes extending in the second direction. The seed layer and the insulator layer each comprise material having a refractive index that is lower than the electro-optical channel.

A wafer having relaxation moduli different by 450 GPa or less, as determined by dynamic mechanical analysis, when loaded to 1 N and 18 N with a loading rate of 0.1 N/min at a temperature of 25° C.

A vapor phase growth apparatus of an embodiment includes: a reactor; a first gas chamber provided above the reactor, a first process gas being introduced into the first gas chamber; a plurality of first gas conduits for supplying the first process gas from the first gas chamber to the reactor, each of the first gas conduits having a predetermined length; and a first adjustment conduit inserted to an upper side of one of the plurality of first gas conduits. The first adjustment conduit has as annular protrusion provided on an outer periphery of an upper end portion and is removable from the first gas conduit.