Charging effects in gold nanoclusters grown on octanedithiol layers

Strong interaction of gold with the terminal sulfur atoms of dithiol molecu les on Au(111) effectively suppresses the penetration of deposited Au atoms through the dithiol layer and results in the formation of homogeneous Au n anoclusters. These nanoclusters, 10-15 Angstrom (sigma <2 Angstrom) in heig ht, spread over the surface with a density of similar to1.2x10(13)/cm(2) fo r coverage between 0.25-2.5 monolayers. Decoupling of the clusters from Au( 111) by the octanedithiol layer (similar to 12 Angstrom in thickness) and t he small self-capacitance of these nanoparticles (10(-19)-10(-18) F) make i t possible to observe both the Coulomb blockade in scanning tunneling spect roscopy and the Au 4f core level shifts in x-ray photoelectron spectroscopy at room temperature. Both phenomena can be attributed to a common physical origin-e(2)/2C-the Coulomb energy of charged particles. (C) 2001 American Institute of Physics.