Nanocrystalline diamond thin films are grown on silicon and glass substrates by microwave plasma (MP)CVD from a gas mixture of methane and hydrogen at low substrate temperatures. The initial stages of diamond growth, i.e., i) the growth of individual nanometer-sized crystals and clusters, and ii) coalescence into a continuous layer, are investigated by diverse analytic techniques. Atomic force microscopy (AFM) measurements reveal nearly unchanging surface roughness up to 40 min. X-ray photoelectron spectroscopy (XPS) measurements detect changing of the surface composition from the very beginning of the growth process. The rapid carbon increase is assigned to the enlarging of the grown crystals and clusters. Scanning electron microscopy (SEM) images indicate a possible lateral growth type. The found dependences indicate that a two-dimensional growth mode takes place at low substrate temperatures. Grown nanocrystalline diamond films are optically transparent in a wide spectral range, and exhibit a high refractive index of 2.34.

No abstract

No abstract

Surprisingly large difference between inelastic mean-free path (IMFP) values of signal electrons calculated from optical data and from the predictive TPP-2M formulae for diamond or graphite has motivated us to verify both sources of IMFP by measuring these values using different method. Thin, perfectly transparent nanocrystalline diamond films were characterized by x-ray induced photoelectron and Auger electron spectroscopy. Elastic peak electron spectroscopy measurements and the Monte Carlo calculations of electron transport were applied to determine the IMFPs for medium electron energy. The surface energy losses were also considered when evaluating these IMFPs.