LANGMUIR-BLODGETT-FILMS OF THIOL-CAPPED GOLD NANOCLUSTERS - FABRICATION AND ELECTRICAL-PROPERTIES

Surface-modified nanoparticles are increasingly studied for their pote ntial applications in the field of information processing. Here the La ngmuir-Blodgett technique is used to prepare monolayers of dodecanethi ol-capped gold nanoparticles (2.9 nm diameter) over macroscopic dimens ions. Combining optical microscopy on the Langmuir film and scanning f orce microscopy (SFM) on transferred films, it is shown that the quali ty of the films is optimized in the 6-8 mN/m range. The dodecanethiol is displaced in situ by dipping the film in a solution of 2,5 ''-bis(a cetylthio)-5,2',5',2 ''-terthienyl (T3) which interconnects the cluste rs. After dipping in the T3 solution, the conductivity of the monolaye r increases up to 10(-3) Ohm(-1)/cm. The non-linear I-V characteristic s measured on interdigitated electrodes and the non-linear scanning tu nnelling spectroscopy (STS) I-V curves are tentatively explained withi n the frame of the Coulomb blockade theory. (C) 1998 Elsevier Science S.A. All rights reserved.