Single crystal diamond tips with perfect pyramidal geometry were obtained by a combination of chemical vapor deposition and selective oxidation of polycrystalline films. The parameters of the deposition process were chosen to provide growth of a textured film consisting of micrometer sized diamond crystallites embedded into nanodiamond ballas-like material. The heating of the film in an air environment was used for selective oxidation of the nanodiamond component. The films obtained contain free standing pyramidal single crystal diamond tips oriented by their apexes to the substrate surface. The tips were used for the fabrication of atomic force microscopy probes and their evaluation in comparison to common silicon probes.

Luminescent properties of needle-like single crystal diamonds are investigated in a wide range of wavelength. The luminescent spectra with zero phonon lines centered at 389, 442, 468, 534, 563, 575, and 738 nm are detected using excitation by photons and electrons. Obtained photo-and cathodo-luminescent (PL and CL) spectra indicate presence in the singlecrystal diamond needles of nitrogen-and silicon-vacancy centers as well as substitutional or/and interstitials related to these atomic impurities. The dependencies of PL intensities of the 575 and 738 nm lines (related, correspondingly, to nitrogen-and silicon-vacancy centers) on excitation wavelength are determined. Time-resolved measurements are performed for the 575 nm PL line. The luminescence decay behavior for this line demonstrates the presence of recombination processes with characteristic times of about 28 ns (on 200 ns time scale) and 2.8 ns (on 20 ns time scale).

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The graphite films of nanometer thickness were produced by condensation of carbon from gaseous phase onto polycrystalline nickel. The films have wrinkled surface with the atomically flat regions separated by the ridges. Together with a net of randomly oriented ridges the periodically ordered wrinkles have been observed. Exposure of the grown graphite films in air leads to appearance of gaseous blisters gradually growing with time. We propose explanations of the mechanisms responsible for formation of these topology peculiarities.

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Electron field emission properties of nanocarbon films produced by plasmaenhanced chemical vapor deposition (PECVD) were investigated. The films contained nanostructured diamond and graphitic components in different ratios depending on the parameters of the deposition process. Low threshold fields in the range of 1-2 V mm À1 (at 0.1 mA cm À2 ) are detected for all types of the studied films. It is found that the scrolled graphene structures, contained in the film material, are responsible for the field emission. The individual graphene scrolls show standard Fowler-Nordheim behavior and sustained maximum field emission currents of several microamperes. Longtime field emission at moderate currents causes partial destruction of the scrolls that significantly changed the threshold field and emission site density of the films. Obtained results show that PECVD growth and post-treatments allow monitoring of the amount and heights of emission centers providing tailored field emission properties of nanocarbon films for particular applications in vacuum electronic devices.

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