Enhancing nanocrystalline diamond surface conductivity by deposition temperature and chemical post-processing

The surface conductivity of nanocrystalline diamond (NCD) films as a function of deposition temperature and chemical post-processing was characterized by current-voltage measurements using co-planar Au electrodes. Raman spectroscopy was applied to investigate the bulk quality of NCD films and characterize the relative amounts of sp diamond phase in the volume. The surface material properties and morphology were studied using atomic force microscopy (AFM) in tapping and phase detection regimes. The results indicate that the chemical post-processing of as grown NCD films by boiling in acid and re-hydrogenation leads to a significant increase in order of 10(-7) (Omega/square)(-1). As a function of the deposition temperature (with re-hydrogenation temperature kept constant) the surface conductivity of nanocrystalline diamond films shows optimum around 60 degrees C. This enhancement is attributed to the lowest amount of sp(2) phase on the surface. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim