Speaker: Dr. Ksenia Makarenko
Affiliation: Department of Chemistry, NUS
Host: Dr Massimo Spina (CA2DM, NUS)
Abstract Details: Downscaling of conventional semiconductor electronics becomes more and more challenging. Despite the large number of proposed functional building blocks, e.g., metallic nanoparticles (NPs), semiconductor nanocrystals or individual molecules, reliable contacting of such structures to electrical circuitry has proven to be a challenging task. We developed a novel bottom-up approach for the fabrication of high-quality single-electron transistors (SETs) that can easily be contacted electrically in a controllable manner. Our approach employs self-assembly of a single Au NP, acting as a SET, to Au NRs, forming the electrical leads to macroscopic electrodes. Thus, the nanoscale junctions between the nanoobject of interest (viz. the Au NP SET) and the electrical contacts are already formed in the NP/NR solution before dispersing the bottom-up formed assemblies on the substrate. The SETs, with organic molecules (1,8-octanedithiol, OPE3) acting as tunnelling barriers, are controlled by a source-drain voltage applied between the leads and a gate voltage applied to the substrate (working as a back gate). Low-temperature electron transport measurements reveal exemplary single-electron tunnelling characteristics. We also show that the SET behaviour can be significantly changed, post-fabrication, using molecular exchange of the tunnel barriers, demonstrating tunability of the assemblies. Moreover, we characterize electron transport through a parallel metallic SET system. The double island also forms a nanoscale hybrid interferometer, where we studied coherent electron transport through organic molecular layers. We observed indications that transport through the self-assembled monolayers can indeed be quantum coherent if we are in the right operating regime. The present results form a promising proof-of-principle of the versatility and high-quality of bottom-up nanoelectronics, and controlled fabrication of (quantum-coherent) nanoelectronic devices.

About The Speaker: Research Fellow, Department of Chemistry, NUS

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