title: Modifying the Interface Edge to Control the Electrical Transport Properties of Nanocontacts to Nanowires.
abstract: Selecting the electrical properties of nanomaterials is essential if their potential as manufacturable devices is to be reached. Here, we show that the addition or removal of native semiconductor material at the edge of a nanocontact can be used to determine the electrical transport properties of metal-nanowire interfaces. While the transport properties of as-grown Au nanocatalyst contacts to semiconductor nanowires are well-studied, there are few techniques that have been explored to modify the electrical behavior. In this work, we use an iterative analytical process that directly correlates multiprobe transport measurements with subsequent aberration-corrected scanning transmission electron microscopy to study the effects of chemical processes that create structural changes at the contact interface edge. A strong metal-support interaction that encapsulates the Au nanocontacts over time, adding ZnO material to the edge region, gives rise to ohmic transport behavior due to the enhanced quantum-mechanical tunneling path. Removal of the extraneous material at the Au-nanowire interface eliminates the edge-tunneling path, producing a range of transport behavior that is dependent on the final interface quality. These results demonstrate chemically driven processes that can be factored into nanowire-device design to select the final properties.
authors.forename: Alex M
authors.identifier: 0000-0002-6258-2187
authors.initials: AM
authors.lastname: Lord
authors.affiliation: SuperSTEM Laboratory, SFTC Daresbury Campus , Keckwick Lane, Daresbury WA4 4AD, United Kingdom.
authors.forename: Quentin M
authors.initials: QM
authors.lastname: Ramasse
authors.affiliation: SuperSTEM Laboratory, SFTC Daresbury Campus , Keckwick Lane, Daresbury WA4 4AD, United Kingdom.
authors.forename: Despoina M
authors.initials: DM
authors.lastname: Kepaptsoglou
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Evans
authors.affiliation: Cardiff Catalysis Institute, School of Chemistry, Cardiff University , Park Place, Cardiff CF10 3AT, United Kingdom.
authors.forename: Philip R
authors.identifier: 0000-0003-4394-766X
authors.initials: PR
authors.lastname: Davies
authors.affiliation: Institute for Materials Research, University of Leeds , Leeds, LS2 9JT United Kingdom.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Ward
authors.forename: Steve P
authors.initials: SP
authors.lastname: Wilks
keywords: Nanowires; ZnO; aberration-corrected scanning transmission electron microscopy; electrical contacts; strong metal−support interaction; tunneling edge effect