title: A chemically-responsive nanojunction within a silver nanowire.
abstract: The formation of a nanometer-scale chemically responsive junction (CRJ) within a silver nanowire is described. A silver nanowire was first prepared on glass using the lithographically patterned nanowire electrodeposition method. A 1-5 nm gap was formed in this wire by electromigration. Finally, this gap was reconnected by applying a voltage ramp to the nanowire resulting in the formation of a resistive, ohmic CRJ. Exposure of this CRJ-containing nanowire to ammonia (NH(3)) induced a rapid (<30 s) and reversible resistance change that was as large as ΔR/R(0) = (+)138% in 7% NH(3) and observable down to 500 ppm NH(3). Exposure to water vapor produced a weaker resistance increase of ΔR/R(0,H(2)O) = (+)10-15% (for 2.3% water) while nitrogen dioxide (NO(2)) exposure induced a stronger concentration-normalized resistance decrease of ΔR/R(0,NO(2)) = (-)10-15% (for 500 ppm NO(2)). The proposed mechanism of the resistance response for a CRJ, supported by temperature-dependent measurements of the conductivity for CRJs and density functional theory calculations, is that semiconducting p-type Ag(x)O is formed within the CRJ and the binding of molecules to this Ag(x)O modulates its electrical resistance.
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697-2025, USA.
authors.forename: Wendong
authors.initials: W
authors.lastname: Xing
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
authors.forename: Sheng-Chin
authors.initials: SC
authors.lastname: Kung
authors.forename: Keith C
authors.initials: KC
authors.lastname: Donavan
authors.forename: Wenbo
authors.initials: W
authors.lastname: Yan
authors.forename: Ruqian
authors.initials: R
authors.lastname: Wu
authors.forename: Reginald M
authors.initials: RM
authors.lastname: Penner
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004553:Electric Conductivity; D004867:Equipment Design; D019544:Equipment Failure Analysis; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D012666:Semiconductors; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver