Robust nanogap electrodes for nanodevices with a separation of 3.0 1.7 nm were simultaneouslymass-produced at a yield of 90% by a combination of electron beam lithography (EBL) and electrolessgold plating (EGP). Nanogap electrodes demonstrated their robustness as they maintained their structure unchanged up to temperatures of 170 C, during the isotropic oxygen plasma ashing removalof the amorphous carbon overlayer resulting from scanning electron microscopy observations, therefore maintaining their surface reactivity for EGP and formation of a self-assembled monolayer. A gold layer grows over the electrode surface during EGP, narrowing the separation between theelectrodes; growth stops around 3 nm due to a self-termination phenomenon. This is the main factor in the high yield and reproducibility of the EGP process because it prevents contact between the electrodes. A 90% yield is achieved by also controlling the etching and physisorption of gold clusters, which is accomplished by reduction of triiodide ions and heat treatment of the EGP solution,respectively. A mixed self-assembled monolayer of octanethiol and decanedithiol can be formed at thesurface of the nanogap electrodes after the oxygen plasma treatment, and decanethiol-protected Au nanoparticles were chemisorbed between the self-terminated nanogap electrodes via decanedithiol.Chemically assembled single-electron transistors based on the nanogap electrodes exhibit ideal, stable,and reproducible Coulomb diamonds
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