AU PARTICLE DEPOSITION ONTO SELF-ASSEMBLED MONOLAYERS OF THIOL AND DITHIOL MOLECULES

Gold depositions on self-assembled monolayers (SAMs) of thiol (HS(CH2) (7)CH3) and dithiol (HS(CH2)(n)SH, n = 6, 8, 10) molecules were invest igated by a scanning tunneling microscope in air. In the case of thiol s, evaporated gold atoms were found to penetrate and form monoatomic h eight islands under the SAMs. On the contrary, gold deposition onto th e dithiols resulted in the formation of the gold particles on top of t he SAMs. Each Au particle is estimated to have similar to 200 atoms an d this size is independent of Au coverage, at least below 1 ML. The el ectrical properties such as Coulomb blockade were also studied by scan ning tunneling spectroscopy. (C) 1998 Elsevier Science B.V. All rights reserved.