Tunable single-electron tunneling behavior of ligand-stabilized gold particles on self-assembled monolayers - art. no. 035403

A series of heptanethiol-stabilized gold particles with narrowly distribute d core sizes ranging from similar to1.8 to similar to 15 nm were synthesize d and deposited on self-assembled alkanethiol monolayers. The current-volta ge characteristics were studied systematically by scanning tunneling micros copy and scanning tunneling spectroscopy, and the results correlate well wi th the gold core sizes. While equidistant staircases originating from the C oulomb blockade (CB) effect are observed for large particles (greater than or equal to4.6 nm), irregular staircases are observed for small particles ( nominal size of 1.8 nm). The latter indicates that both the CB effect and d iscrete quantum energy levels contribute to the current-voltage spectra. Fu rthermore, single-electron tunneling behavior are shown to be tunable eithe r by varying the gold particle size or by adjusting the tip-particle distan ce.