Nanocrystalline diamond produced by direct current micro-plasma: Investigation of growth dynamics

In this work, the growth dynamics of nanocrystalline diamond, deposited on molybdenum and silicon substrates with a direct-current micro-plasma device, is experimentally investigated. No substrate pre-treatment was performed and comparable deposition conditions were adopted for both substrates, addressing both morphological and structural properties for various deposition times. An extensive characterization of the resulting different stages of growth was achieved, exploiting scanning electron microscopy, X-ray diffraction and Raman spectroscopy at two wavelenghts (both visible and UV). The deposition of graphite upon formation of a carbide layer prior to diamond nucleation has been found to be the triggering step towards diamond growth on both substrates, but with a different growth kinetics. Besides showing the potential of the adopted deposition method and characterization strategy, our results also show the possibility of producing nanocrystalline diamond with reduced deposition times and without any substrate pre-treatment.