High-resolution electron microscopy and electron spin resonance studies oncubic boron nitride crystals made by high-pressure/high-temperature synthesis

Cubic boron nitride (c-BN) crystals synthesised at high pressures and tempe ratures are analysed by optical microscopy, transmission electron microscop y, electron diffraction and electron spin resonance. For various growth con ditions, the results of these studies indicate that the c-BN crystals conta in defects and impurities. This is the first time that dislocation cores ha ve been revealed in c-BN at the atomic level. Atomic resolution at extended dislocations allows us to determine the stacking-fault energy in c-BN, yie lding a mean value of 191+/-15 mJ m(-2). This value, which is reported for the first time for c-BN, is of the same order of magnitude as in diamond. ( C) 1999 Elsevier Science S.A. All rights reserved.