Thiol-terminated monolayers on oxide-free Si: assembly of semiconductor-alkyl-S-metal junctions.
Self-assembled monolayers formed by thermal hydrosilylation of a trifluoroacetyl-protected alkenylthiol on Si-H surfaces, followed by removal of the protecting groups, yield essentially oxide-free monolayers suitable for the formation of Si-C11H22-S-Hg and Si-C11H22-S-Au junctions in which the alkyl chains are chemically bound to the silicon surface (via Si-C bonds) and the metal electrode (via Hg-S or Au-S bonds). Two barriers to charge transport are present in the system: at low bias the current is temperature activated and hence limited by thermionic emission over the Schottky barrier in the silicon, whereas as at high bias transport is limited by tunneling through the organic monolayer. The thiol-terminated monolayer on oxide-free silicon provides a well-characterized system allowing a careful study of the importance of the interfacial bond to the metal electrode for current transport through saturated molecules.
Böcking
Till
T
School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia.
Salomon
Adi
A
Cahen
David
D
Gooding
J Justin
JJ
D002627:Chemistry, Physical / Q000379:methods*; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D004581:Electronics; D006046:Gold / Q000737:chemistry; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry; D012666:Semiconductors; D012825:Silicon / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D014965:X-Rays
D008670:Metals; D010087:Oxides; D013438:Sulfhydryl Compounds; D013455:Sulfur; D006046:Gold; D012825:Silicon