Nanocatalysts Assisted Growth of Diamond Films on Si by Hot Filament CVD

摘要

Four different catalysts, nano-Ni, diamond powder, mixture of nano-Ni/diamond powder, and ultrasonicated nanodiamond seed, were used to activate Si wafers for diamond film growth by hot filament CVD (HFCVD) Diamond crystals were shown to grow directly on both large diamond powder and small nanodiamond seed, but a better crystallinity of diamond film was observed on the ultrasonicated nanodiamond seeded Si substrate. On the other hand, nano-Ni nanocatalysts seem to promote the formation of amorphous and/or graphitic-like carbon at the initial growth of diamond films. The subsequent nucleation and growth of diamond crystals on top of the amorphous carbon layer were followed to generate the spherical diamond particles and clusters prior to coalescence into continuous diamond films. Moreover, the mixture of nano-Ni/diamond powder catalyst tend to promote the formation of a mixed of amorphous and crystallite diamond structures as characterized by TEM, Raman, and XRD techniques.