Abstract
Enhanced nucleation behavior for ultra-nanocrystalline diamond on Si-substrates via the utilization of Mo-coating was observed. Spectroscopic examinations indicated that the mechanism of enhancement is the formation of Mo 2 C phase, which hindered the inward diffusion of carbon species into the substrate materials. The diamonds may either nucleate directly on Mo 2 C-layer or via the formation of transition phases, the graphite. The incoming carbons may also react with Mo 2 C phase to form MoC phase or form the graphite phase prior to the induction of diamond nuclei. In all cases, the carbons accumulated rapidly due the presence of a Mo 2 C (or MoC) layer, triggering the formation of diamond nuclei. © 2009 Elsevier B.V. All rights reserved.