Spontaneous S-Si bonding of alkanethiols to Si(111)-H: towards Si-molecule-Si circuits.

Autor: Peiris CR; School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University Bentley WA 6102 Australia nadim.darwish@curtin.edu.au., Ciampi S; School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University Bentley WA 6102 Australia nadim.darwish@curtin.edu.au., Dief EM; School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University Bentley WA 6102 Australia nadim.darwish@curtin.edu.au., Zhang J; School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University Bentley WA 6102 Australia nadim.darwish@curtin.edu.au., Canfield PJ; International Centre for Quantum and Molecular Structures, School of Physics, Shanghai University Shanghai 200444 China.; School of Chemistry, The University of Sydney NSW 2006 Australia., Le Brun AP; Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organization (ANSTO) Lucas Heights NSW 2234 Australia., Kosov DS; College of Science and Engineering, James Cook University Townsville QLD 4811 Australia daniel.kosov@jcu.edu.au., Reimers JR; International Centre for Quantum and Molecular Structures, School of Physics, Shanghai University Shanghai 200444 China.; School of Mathematical and Physical Sciences, University of Technology Sydney NSW 2007 Australia Jeffrey.Reimers@uts.edu.au., Darwish N; School of Molecular and Life Sciences, Curtin Institute of Functional Molecules and Interfaces, Curtin University Bentley WA 6102 Australia nadim.darwish@curtin.edu.au.
Jazyk: angličtina
Zdroj: Chemical science [Chem Sci] 2020 Apr 27; Vol. 11 (20), pp. 5246-5256. Date of Electronic Publication: 2020 Apr 27.
DOI: 10.1039/d0sc01073a
Abstrakt: We report the synthesis of covalently linked self-assembled monolayers (SAMs) on silicon surfaces, using mild conditions, in a way that is compatible with silicon-electronics fabrication technologies. In molecular electronics, SAMs of functional molecules tethered to gold via sulfur linkages dominate, but these devices are not robust in design and not amenable to scalable manufacture. Whereas covalent bonding to silicon has long been recognized as an attractive alternative, only formation processes involving high temperature and/or pressure, strong chemicals, or irradiation are known. To make molecular devices on silicon under mild conditions with properties reminiscent of Au-S ones, we exploit the susceptibility of thiols to oxidation by dissolved O 2 , initiating free-radical polymerization mechanisms without causing oxidative damage to the surface. Without thiols present, dissolved O 2 would normally oxidize the silicon and hence reaction conditions such as these have been strenuously avoided in the past. The surface coverage on Si(111)-H is measured to be very high, 75% of a full monolayer, with density-functional theory calculations used to profile spontaneous reaction mechanisms. The impact of the Si-S chemistry in single-molecule electronics is demonstrated using STM-junction approaches by forming Si-hexanedithiol-Si junctions. Si-S contacts result in single-molecule wires that are mechanically stable, with an average lifetime at room temperature of 2.7 s, which is five folds higher than that reported for conventional molecular junctions formed between gold electrodes. The enhanced "ON" lifetime of this single-molecule circuit enables previously inaccessible electrical measurements on single molecules.
Competing Interests: There are no conflicts to declare.
(This journal is © The Royal Society of Chemistry.)
Databáze: MEDLINE
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