Structure Matters: Correlating Temperature Dependent Electrical Transport Through Alkyl Monolayers With Vibrational And Photoelectron Spectroscopies

dc.contributor.ISNI0000 0000 4239 3958 (Chabal, YJ)
dc.contributor.LCNA89624105 (Chabal, YJ)
dc.contributor.authorShpaisman, Hagayen_US
dc.contributor.authorSeitz, Oliveren_US
dc.contributor.authorYaffe, Omeren_US
dc.contributor.authorRoodenko, Ecatherina (Katy)en_US
dc.contributor.authorScheres, Lucen_US
dc.contributor.authorZuilhof, Hanen_US
dc.contributor.authorChabal, Yves J.en_US
dc.contributor.authorSueyoshi, Tomokien_US
dc.contributor.authorKera, Satoshien_US
dc.contributor.authorUeno, Nobuoen_US
dc.contributor.authorVilan, Ayeleten_US
dc.contributor.authorCahen, Daviden_US
dc.description.abstractFreezing out of molecular motion and increased molecular tilt enhance the efficiency of electron transport through alkyl chain monolayers that are directly chemically bound to oxide-free Si. As a result, the current across such monolayers increases as the temperature decreases from room temperature to similar to 80 K, i.e., opposite to thermally activated transport such as hopping or semiconductor transport. The 30-fold change for transport through an 18-carbon long alkyl monolayer is several times the resistance change for actual metals over this range. FTIR vibrational spectroscopic measurements indicate that cooling increases the packing density and reduces the motional freedom of the alkyl chains by first stretching the chains and then gradually tilting the adsorbed molecules away from the surface normal. Ultraviolet photoelectron spectroscopy shows drastic sharpening of the valence band structure as the temperature decreases, which we ascribe to decreased electron-phonon coupling. Although conformational changes are typical in soft molecular systems, in molecular electronics they are rarely observed experimentally or considered theoretically. Our findings, though, indicate that the molecular conformational changes are a prominent feature, which imply behavior that differs qualitatively from that described by models of electronic transport through inorganic mesoscopic solids. © 2012 The Royal Society of Chemistryen_US
dc.identifier.citationShpaisman, Hagay, Oliver Seitz, Omer Yaffe, Katy Roodenko, et al. 2012. "Structure Matters: Correlating temperature dependent electrical transport through alkyl monolayers with vibrational and photoelectron spectroscopies." Chemical Science 3(3): 851-862.en_US
dc.rights© 2012 The Royal Society of Chemistryen_US
dc.source.journalChemical Scienceen_US
dc.subjectMonomolecular filmsen_US
dc.subjectMolecular electronicsen_US
dc.subjectPhotoelectron spectroscopyen_US
dc.titleStructure Matters: Correlating Temperature Dependent Electrical Transport Through Alkyl Monolayers With Vibrational And Photoelectron Spectroscopiesen_US


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