Comparison of the growth and properties of ultrananocrystalline diamond and nanocrystalline diamond

In this paper we compare and contrast the growth and properties of ultrananocrystalline (UNCD) and nanocrystalline (NCD) diamond. These two structures, grown from hydrogen poor and hydrogen rich plasmas, respectively, have markedly different structural properties. We characterise the plasmas used for growth with in situ optical emission spectroscopy and dual wavelength pyrometry. The films are characterised with scanning electron microscopy in both plan view and cross section. Raman spectroscopy was used to investigate bonding. Finally we make a clear definition of these two different microstructures.