STM studies of passivated Au nanocrystals immobilised on a passivated Au(111) surface: ordered arrays and single electron tunnelling

We have employed scanning tunnelling microscopy (STM) in ultra-high vacuum (UHV) to explore the assembly and electron transport properties of an order ed layer of passivated gold clusters adsorbed onto an alkanethiol passivate d Au(111) surface. The passivation of the Au(111) surface stabilises the cl uster layer. STM images show ordered hexagonal arrays of the nanoparticles extending over distances >100 nm with a mean nearest neighbour spacing of 6 .5 nm. I-V measurements show a strong non-linear I-V relationship, as well as equidistant steps of width similar to0.15 V above a bias voltage of simi lar to2 V, attributed to a Coulomb staircase, i.e., single electron chargin g, in this structure. (C) 2000 Elsevier Science B.V, All rights reserved.