Superhard Phases of Simple Substances and Binary Compounds of the B-C-N-O System: from Diamond to the Latest Results (a Review)

The basic known and hypothetic one- and two-element phases of the B-C-N-O system (both superhard phases having diamond and boron structures and precursors to synthesize them) are described. The attention has been given to the structure, basic mechanical properties, and methods to identify and characterize the materials. For some phases that have been recently described in the literature the synthesis conditions at high pressures and temperatures are indicated.Comment: Review on superhard B-C-N-O phase

Study of defects in chemical-vapor-deposited diamond films by cross-sectional cathodoluminescence

Cathodoluminescence (CL) in the scanning electron microscope has been used to study the upper surface and cross-sectional samples of chemical vapor deposited diamond films. The CL emission is mainly localized at the grain boundaries of the columnar grains. The concentration of dislocation related radiative centers is higher in boundaries parallel to the growth axis than in boundaries parallel to the sample surface. The opposite occurs with the concentration of centers related to the presence of nitrogen