Statistical Analysis of Electronic Transport Through Chemisorbed Versus Physisorbed Alkanethiol Self-Assembled Monolayers

We fabricate microscale via-hole structure molecular electronic devices using various lengths of alkanemonothiol and alkanedithiol self-assembled monolayers (SAMs) and characterize their charge transport properties. From the statistical analysis of the transport properties of these SAMs, we have found that the conductance of alkanedithiols is higher about an order of magnitude than that of alkanemonothiols, which is due to the different nature of metal-molecule contacts, i.e., physisorbed versus chemisorbed contacts. However, the transport decay coefficients that can be obtained from the length-dependent transport characterization are almost identical for the two molecular systems.