Room temperature Coulomb staircase on pure and uniform surface-capped gold nanoparticles

A clear Coulomb staircase has been observed by using scanning tunneling microscopy in a new nanostructure with a surface-capped tunneling layer on the gold particle instead of a conventional tunneling thin film between the gold particle and substrate electrode. The occurrence of the Coulomb staircase was due to the pure and uniform surface-capped gold particles prepared by an efficient photochemical formation in a new kind of reducing nonaqueous system. As a comparison, the phenomenon cannot take place in the same nanostructure as above with the gold particle prepared by photochemical reduction in aqueous solution or typical chemical reduction.