Conductive Atomic Force Microscopy Study of Electron Transport Through Diazonium Derived Films and Mixed – Mode Bonded Layers on Gold and Carbon Surfaces

Abstract

For Molecular Electronics to become a viable replacement or complitment to current elec- tronic devices a fundamental understanding of device operation and functionality is needed. This work explores electron transport through diazonium derived molecular junctions via conductive atomic force microscopy to provide insight into the scalability of molecular de- vices. The attenuation coefficient and electron transport properties of nitroazobenzene on carbon; were found to be consistent with larger ensemble molecular junctions. Further, ap- plied force significantly decreased the resistance through the layer due to reduced tunneling distance and increased contact area. Electron transport through nitroazobenzene was ex- tended to gold surfaces and found to be in agreement with studies on carbon. Investigation of mixed-mode bonded layers of nitroazobenzene and dodecanethiol determined that surface coverage was controllable through solution concentration and sweep rate. Qualitatively it was observed that conductivity increased with nitroazobenzene coverage.