Z-contrast imaging and electron energy-loss spectroscopy analysis of chromium-doped diamond-like carbon films

Metal-doped diamond-like carbon films were produced for the purpose of an electrochemical nanoelectrode. In this study we use Z-contrast scanning transmission electron microscopy to directly observe metal cluster formation and distributions within the chromium-doped carbon films. At low doping (similar to 6 at. % Cr), Cr is uniformly distributed within the C matrix; at high doping (similar to 12 at. % Cr), Cr-rich clusters are formed. Analyzing electron energy loss spectroscopy Cr L-2,L-3 white line ratios, we find that the Cr tends to be metallic-like when it is uniformly distributed in the C matrix and carbide-like in the Cr-rich clusters. The carbon is more diamond-like at low doping and more graphite/carbide-like at high doping according to the sp(2)/sp(3) electron percentage measurements. (C) 1999 American Institute of Physics. [S0003-6951(99)00844-X].