To investigate the mechanism of the diamond surface conductivity, temper experiments have been performed on chemical-vapor-deposited (CVD) diamond films under vacuum conditions. The surface conductivity of these films was measured as a function of temperature and in contact with different gas atmospheres. These results were compared with those obtained by gas evolution experiments performed on CVD diamond samples of the same kind, demonstrating the possible role of CO adsorption to the surface conductivity

In a recent paper [Phys. Rev. Lett. 84, 3658 (2000)] a direct diamond epitaxy on the silicon substrate is demonstrated not only at the interface formed during the growth process but also at the nucleation sites. Small (001) terraces with dimensions of several atomic distances at the site of nucleation are observed due to the roughening of silicon surface and lead to the grain misorientation. To further improve the understanding of the subject the microstructure and interfaces in diamond films on silicon substrates grown in the stages of the bias-enhanced nucleation (BEN) and the initial crystal growth were studied by means of atomic force microscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. It is showed that the roughness of the wafer starts to incrase from the beginning of the BEN and the renucleation on existing crystallites induced by the ion bombardement leading to the loss of epitaxy