ROOM-TEMPERATURE COULOMB STAIRCASE ON PURE AND UNIFORM SURFACE-CAPPEDGOLD NANOPARTICLES

A clear Coulomb staircase has been observed by using scanning tunnelin g microscopy in a new nanostructure with a surface-capped tunneling la yer 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 g old particles prepared by an efficient photochemical formation in a ne w kind of reducing nonaqueous system. As a comparison, the phenomenon cannot take place in the same nanostructure as above with the gold par ticle prepared by photochemical reduction in aqueous solution or typic al chemical reduction. (C) 1998 Elsevier Science B.V. All rights reser ved.