title: Direct structural observation of a molecular junction by high-energy x-ray reflectometry.
abstract: We report a direct angstrom resolution measurement of the structure of a molecular-size electronic junction comprising a single (or a double) layer of alkyl-thiol and alkyl-silane molecules at the buried interface between solid silicon and liquid mercury. The high-energy synchrotron x-ray measurements reveal densely packed layers comprising roughly interface-normal molecules. The monolayer's thickness is found to be 3-4 A larger than that of similar layers at the free surfaces of both mercury and silicon. The origins of this and the other unusual features detected are discussed in this article. Measurements of the bilayer junction with an applied potential did not show visible changes in the surface normal structure.
authors.affiliation: Department of Chemistry, Columbia University, New York, NY 10027, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Lefenfeld
authors.forename: Julian
authors.initials: J
authors.lastname: Baumert
authors.forename: Eli
authors.initials: E
authors.lastname: Sloutskin
authors.forename: Ivan
authors.initials: I
authors.lastname: Kuzmenko
authors.forename: Peter
authors.initials: P
authors.lastname: Pershan
authors.forename: Moshe
authors.initials: M
authors.lastname: Deutsch
authors.forename: Colin
authors.initials: C
authors.lastname: Nuckolls
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Ocko