Noriko Kurihara

Blue Electroluminescence of Thin-Film Diamond Made by the Hot-Filament Method

Blue electroluminescence has been observed in thin-film diamond deposited on a substrate when a mixture of methane and hydrogen gases react under heat treatment by tungsten filament. The diamond active layer is sandwiched between metal oxide insulating layers (HfO2 and Al2O3) which are formed by evaporation of metal oxides in oxygen plasma. Indium tin oxide film is used as a transparent electrode. The electroluminescence spectrum shows the peak at 435 nm and luminance is 3.6 cd/m2 at an applied voltage of 400 V.

Epitaxial growth of graphite layer on {111} surface of vapor‐deposited diamond

The epitaxial growth of graphite layer on {111} surface of vapor‐deposited diamond has been found by observations of diffraction patterns and high resolution lattice images. While the lattice spacing in the ab plane of the epitaxial graphite is the same as that of bulk graphite, the lattice spacing in the c direction is in the range of 0.33–0.42 nm depending on the thickness of the graphite layer. This is the first experimental evidence for the generation of graphite on the {111} surface of vapor‐deposited diamond proposed by Frenklach and Spear [J. Mater. Res. 3, 133 (1988)].

Triangular Structures on {111} Surfaces of Diamond Crystals Synthesized by the Hot-Filament CVD Method

The morphology of the diamond crystal deposited by a hot-filament method has been studied by a high-resolution scanning electron microscope to elucidate the mechanism of the crystal growth. The growth of {111} faces is multinucleation, and the {111} surface consists of both many small triangles whose orientations are the same as those of the original {111} face of a cubo-octahedron and triangular pits surrounded by three triangles. The appearance of three {110} surfaces at the edge of the {111} surface is possibly explained by the inhomogeneity of the active carbon concentration oh the {111} surface.

Size Dependence of Morphology of Diamond Surfaces Prepared by DC Arc Plasma Jet Chemical Vapor Deposition

The size dependence of the surface morphology of a diamond crystal prepared by the dc arc plasma jet chemical vapor deposition (CVD) is observed using a high-resolution field-emission scanning electron microscope (FE-SEM). The difference in the change of the surface morphology between the {111} surface and the {100} surface is caused by the difference in the growth mode; the {111} surface is formed by the multi-nucleation growth mode, whereas the {100} surface is formed by the single nucleation growth mode.

Assignment of New Facets Developing on {111} Surfaces of Vapor-Deposited Diamond Crystals

The morphology of diamond particles synthesized by hot-filament chemical vapor deposition have been studied for assignment of the new and flat surfaces developing on rough {111} surfaces of a cubo-octahedron with the increase of crystal size. The new surfaces are assigned to {100} according to the interplanar angle with {100} surfaces of a cubo-octahedron, its smoothness, and the maintenance of the original cubo-octahedron shape with the increase of size, which have been observed by a scanning electron microscope.

Growth Mode of {111} Surfaces of Diamond Crystals Synthesized by Hot-Filament CVD Method

The substate temperature dependence of the morphology and the fine structures on {111} surfaces of diamond crystals have been studied using a high-resolution scanning electron microscope to elucidate the mechanism of the crystal growth. A layer-by-layer crystal growth of the {111} surface is suggested from the fact that the {111} surface structures are the same in diamond crystals deposited at different temperatures in spite of the difference in the shapes of {111} surfaces.