Transport mechanism of self-assembled D-σ-A-thiol monolayers in metal-molecule-metal structure

Transport mechanism of rectifying D-σ-A-SAc molecule in the structure of vertical metal-molecule-metal (MMM) has been investigated by using variable temperature measurement. We successfully synthesized a novel D-σ-A-SAc molecule and fabricated the molecular rectifying array device by using self-assembly technique. The results of variable temperature measurements suggest that electron injection in the interface between electron donor molecule and Ti/Au electrode is dominated by a thermal emission with a barrier height of around 0.29 eV while carrier injection between thiolated A-σ-D molecule and gold electrode is dominated by tunneling with a barrier height of around 0.8 eV. Therefore, we suggest that the origin of rectification comes from energy differences of two interfacial barriers in MMM device.