Session A5 - Molecular Electronics: Challenges for Computing and Sensing.
INVITED session, Monday morning, March 22
524AB, Palais des Congres
Electron devices containing molecules as the active region have been an active area of research over the last few years. This talk presents measurements in a variety of molecular systems to elucidate the transport mechanisms, specifically in self-assembled monolayers (SAMs) using nanometer scale devices. Detailed kinetic studies are necessary to distinguish between different conduction mechanisms; for example, in alkanes temperature-independent electron transport is observed, proving tunneling as the dominant conduction mechanism when defects are eliminated from the device structure. This is distinct from Langmuir-Blodgett films, where only defect or filamentary conduction has been observed. A barrier height of 1.39 +/- 0.01 eV and a zero field decay coefficient of 0.79 /1 0.01 Å-1 are determined for alkanethiols.[1] The results are consistent with inelastic electron tunneling spectroscopy of the molecules in the junction. Deviation from this classic behavior for more complex molecule structures, and a comparison of the differences and pitfalls of various fabrication and characterization approaches, will be discussed.
[1] W. Wang et al., Phys. Rev. B 68, 035416 (2003)