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Issue 22, 2012
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Robust nanogap electrodes by self-terminating electroless gold plating

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Robust nanogap electrodes for nanodevices with a separation of 3.0 ± 1.7 nm were simultaneously mass-produced at a yield of 90% by a combination of electron beam lithography (EBL) and electroless gold 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 removal of 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 the electrodes; 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 the surface 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.

Graphical abstract: Robust nanogap electrodes by self-terminating electroless gold plating

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Publication details

The article was received on 10 Aug 2012, accepted on 11 Sep 2012 and first published on 20 Sep 2012

Article type: Paper
DOI: 10.1039/C2NR32232C
Nanoscale, 2012,4, 7161-7167

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    Robust nanogap electrodes by self-terminating electroless gold plating

    V. M. Serdio V., Y. Azuma, S. Takeshita, T. Muraki, T. Teranishi and Y. Majima, Nanoscale, 2012, 4, 7161
    DOI: 10.1039/C2NR32232C

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