Electronic transport and tip-loading force effect in self-assembled monolayer studied by conducting atomic force microscopy

Charge transport is investigated for self-assembled monolayers (SAMs) with different molecular structures and various molecular lengths using conducting atomic force microscopy. Conduction mechanism for alkanethiol SAMs is investigated and electronic transport parameters such as barrier height phi(B) and tunneling decay coefficient are determined and compared with previously reported results. The effects of tip-loading force on metal-SAMs-metal junction properties for different molecular structures are investigated, indicating that molecules with rigid backbone are more resistive to applied loading force than molecules with flexible backbone. Therefore, different aspect of current-voltage characteristics is expected according to molecular structures under the influence of tip loads. (c) 2005 Elsevier B.V. All rights reserved.