Why is iridium the best substrate for single crystal diamond growth?

The synthesis of heteroepitaxial monocrystalline diamond films has been of technological and scientific interest for several decades. Using chemical vapor deposition techniques, polycrystalline diamond has been successfully grown on many substrates. However, iridium emerges in providing highly oriented films, significantly better than any other transition metals. In the present work we propose an ab initio density functional study of the interaction of diamond with different substrates used experimentally. The origin of iridium's specific behavior is investigated. The kinetics of carbon atoms in the substrate lattice is found to play a key role, determining the nucleation mechanisms and hence the quality of the final diamond film. (c) 2005 American Institute of Physics.