Orientation relationship between chemical vapor deposited diamond and graphite substrates

Diamond was deposited on synthetic graphite, highly oriented pyrolytic graphite and on substrates covered with graphite powder. Scanning electron microscopy and transmission electron microscopy were used to examine the samples. A strong preference for nucleation of diamond on the edges of the graphite sheets was observed. The graphite and the diamond have a preferential orientation relationship in which the diamond (111) plane is parallel to the graphite (0001) plane, and the diamond [11̄0] direction is parallel to the graphite [112̄0] direction. This orientation means that the puckered hexagons in the diamond (111) plane retain the same orientation as the flat hexagons in the original graphite sheet. We conclude that the diamond can nucleate with an epitaxial relationship to the graphite. Some of the edges of the graphite sheets may have been converted to diamond by the atomic hydrogen.