title: Molecular adsorption onto metallic quantum wires.
abstract: We have studied the adsorption of mercaptopropionic acid, 2,2'-bipyridine, and dopamine onto electrochemically fabricated Cu nanowires. The nanowires are atomically thin with conductance quantized near integer multiples of 2e(2)/h. Upon molecular adsorption, the quantized conductance decreases to a fractional value, due to the scattering of the conduction electrons by the adsorbates. The decrease is as high as 50% for the thinnest nanowires whose conductance is at the lowest quantum step, and smaller for thicker nanowires with conductance at higher quantum steps. The adsorbate-induced conductance changes depend on the binding strengths of the molecules to the nanowires, which are in the order of mercaptopropionic acid, 2,2'-bipyridine, and dopamine, from strongest to weakest. The sensitive dependence of the quantized conductance on molecular adsorption may be used for molecular detection.
authors.affiliation: Department of Physics, Florida International University, Miami, Florida 33199, USA.
authors.forename: A
authors.initials: A
authors.lastname: Bogozi
authors.forename: O
authors.initials: O
authors.lastname: Lam
authors.forename: H
authors.initials: H
authors.lastname: He
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: N J
authors.initials: NJ
authors.lastname: Tao
authors.forename: L A
authors.initials: LA
authors.lastname: Nagahara
authors.forename: I
authors.initials: I
authors.lastname: Amlani
authors.forename: R
authors.initials: R
authors.lastname: Tsui