Metal-Single-Molecule-Semiconductor Junctions Formed by a Radical Reaction Bridging Gold and Silicon Electrodes

Chandramalika R. Peiris, Yan B. Vogel, Anton P. Le Brun, Albert C. Aragonès, Michelle L. Coote, Ismael Díez-Pérez, Simone Ciampi, Nadim Darwish

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


Here we report molecular films terminated with diazonium salts moieties at both ends which enables single-molecule contacts between gold and silicon electrodes at open circuit via a radical reaction. We show that the kinetics of film grafting is crystal-facet dependent, being more favorable on ⟨111⟩ than on ⟨100⟩, a finding that adds control over surface chemistry during the device fabrication. The impact of this spontaneous chemistry in single-molecule electronics is demonstrated using STM-break junction approaches by forming metal−single-molecule−semiconductor junctions between silicon and gold source and drain, electrodes. Au−C and Si−C molecule−electrode contacts result in single-molecule wires that are mechanically stable, with an average lifetime at room temperature of 1.1 s, which is 30−400% higher than that reported for conventional molecular junctions formed between gold electrodes using thiol and amine contact groups. The high stability enabled measuring current− voltage properties during the lifetime of the molecular junction. We show that current rectification, which is intrinsic to metal− semiconductor junctions, can be controlled when a single-molecule bridges the gap in the junction. The system changes from being a current rectifier in the absence of a molecular bridge to an ohmic contact when a single molecule is covalently bonded to both silicon and gold electrodes. This study paves the way for the merging of the fields of single-molecule and silicon electronics. 
Original languageEnglish
Pages (from-to)14788-14797
Number of pages10
JournalJournal of The American Chemical Society
Issue number37
Publication statusPublished - 18 Sep 2019
Externally publishedYes


  • Gold electrode
  • silicon electrode
  • Diazonium salts
  • moieties
  • metal-single-molecule-semiconductor junctions
  • molecular electronics


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