EFFECTS OF MORPHOLOGY ON CHARGE TRANSFER PROPERTIES OF ULTRATHIN METALLIC FILMS ON GRAPHITE NANOSTRUCTURES

Abstract

Reportedly, the size and density of the metal nanoparticles considerably alter the work function on
graphitic nanostructures coated with gold, platinum, and chromium. Nanoparticles of gold and
platinum had surface potentials of 1.4 V and 0.6 V, respectively, much greater than the bulk metals'
0.45 V and 0.6 V, respectively. Surface potential (SP) measurements on chromium showed a sign
inversion, with tiny nanoparticles measuring -2 V and bulk chromium -0.9 V. Consistent with the
known doping qualities, the sign shift is shown to be caused by an inversion of the graphite Fermi
level. Charge transfer from metal nanoparticles to graphitic nanostructure is confirmed by a link of
surface potentials with the resultant dipole. For nanoparticles with a size between 0.1 nm and 1 nm,
the charge transfer rose from 0.04 eV to 0.27 eV. These results show that the morphology of the film,
in addition to the metal choice, may affect the electrical structure at the metal-graphene/graphite
interface.