Synthesis and characterization of boron-substituted carbons

Thin films of boron-substituted carbons have been synthesized by chemical vapor deposition. X-ray diffraction measurements showed that the d((002)) value depends both on B at.% in the deposits and on the reaction temperature. Addition of boron increases the crystallinity up to a certain boron concentration, but beyond this critical value, on the contrary, the crystallinity deteriorates as the boron content increases. B-11-NMR indicated that isolated boron atoms are dominant at low boron concentration in the deposits, and that the number of boron-to-boron connected atoms increases rapidly when the boron content is higher. (C) 2000 Elsevier Science Ltd. All rights reserved.