Diamond nucleation by carbon fibers on unscratched substrate by hot-filament chemical vapor deposition

Abstract

In order to overcome the difficulty of nucleation of diamond particles on unscratched substrates by the chemical vapor deposition (CVD) method, carbon fibers are introduced on unscratched substrates as a nucleation site of diamond particles. With assistance of carbon fibers, diamond particles can be synthesized on unscratched silicon substrate from a gas mixture of methane and hydrogen by the hot-filament CVD method. From SEM observations, nucleation of diamond particles has been confirmed on fibers at the beginning of deposition. Fine particles have formed initially on the rugged surface of fibers, and then they grow up to be diamond particles. Detailed SEM observations reveal nucleation has occurred on irregular surfaces such as boundaries on carbon fibers. We propose that nucleation of diamond particles can be controlled by arranging carbon fibers on the substrate without applying any mechanical pretreatment.