Role of film-substrate interface in the internal friction of nanocrystalline diamond films

In light of recent measurements which indicate a dominant role in the low-temperature internal friction for interface-layers of diamond films grown on silicon substrates, the internal friction of a series of four nanocrystalline diamond films was measured. The films, all 0.5 mu m thick, had internal friction silimar in magnitude to those reported before, Q(f)(-1) 4 approximate to 10(-6), below roughly 100 K. However, no dependence on interface-layer structure was found, contrary to expectations. The films did exhibit a low-temperature internal friction peak, at 1-2 K, which was also observed in previous films. Published by Elsevier B.V.