title: Improving the morphological stability of a polycrystalline tungsten nanowire with a carbon shell.
abstract: Polycrystalline tungsten nanowire is studied for its potential as an interconnect for nanodevices. At elevated temperatures arising from Joule heating at high current densities, a bare 40 nm nanowire was observed in situ in a transmission electron microscope to undergo grain grooving that eventually led to its breakage. By overcoating a carbonaceous layer onto the nanowire surface, the tungsten-carbon core-shell structure was found to sustain a much higher current density of about 3 x 10(7) A cm( - 2) before failure, despite significantly higher peak temperature as a result of Joule heating. Failure occurred as a result of a different form of morphological transformation leading finally to breakage by electromigration. These findings suggest that the metal-carbon core-shell structure provides a solution to circumvent morphological instability and increase the current-carrying capability of metallic polycrystalline nanowires.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117576, Singapore.
authors.forename: Guo Feng
authors.initials: GF
authors.lastname: You
authors.forename: Hao
authors.initials: H
authors.lastname: Gong
authors.forename: John T L
authors.initials: JT
authors.lastname: Thong