Atomic-force and Kelvin-probe microscopies were employed in ultrahigh vacuum to image the surface topography and contact potential of the hydrogen-terminated and unterminated surfaces of diamond. A variation of about 25 meV in the contact potential was measured on a length scale of 20 nm and ascribed to differently orientated surface domains resulting from hydrogen-plasma processing of the sample. Shifts in the work function arising from sample heating in vacuum and the adsorption of C₆₀ were measured. The Fermi level was found to be 0.7 and 1.1 eV below the valence band maximum for C₆₀ coverages of 1 and 4 monolayer, respectively.
Copyright 2009 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied physics letters, Vol. 95, Issue 12, pp.123108-1 - 123108-3, and may be found at http://apl.aip.org/applab/v95/i12/p123108_s1