title: Active vacuum brazing of CNT films to metal substrates for superior electron field emission performance.
abstract: The joining of macroscopic films of vertically aligned multiwalled carbon nanotubes (CNTs) to titanium substrates is demonstrated by active vacuum brazing at 820 °C with a Ag-Cu-Ti alloy and at 880 °C with a Cu-Sn-Ti-Zr alloy. The brazing methodology was elaborated in order to enable the production of highly electrically and thermally conductive CNT/metal substrate contacts. The interfacial electrical resistances of the joints were measured to be as low as 0.35Ω. The improved interfacial transport properties in the brazed films lead to superior electron field-emission properties when compared to the as-grown films. An emission current of 150μA was drawn from the brazed nanotubes at an applied electric field of 0.6 Vμm-1. The improvement in electron field-emission is mainly attributed to the reduction of the contact resistance between the nanotubes and the substrate. The joints have high re-melting temperatures up to the solidus temperatures of the alloys; far greater than what is achievable with standard solders, thus expanding the application potential of CNT films to high-current and high-power applications where substantial frictional or resistive heating is expected.
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Rémi
authors.initials: R
authors.lastname: Longtin
authors.forename: Juan
authors.initials: J
authors.lastname: Ramon Sanchez-Valencia
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Ivan
authors.initials: I
authors.lastname: Shorubalko
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Roman
authors.initials: R
authors.lastname: Furrer
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Erwin
authors.initials: E
authors.lastname: Hack
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Hansrudolf
authors.initials: H
authors.lastname: Elsener
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Gröning
authors.affiliation: AIXTRON Ltd, Buckingway Business Park, Anderson Road, Swavesey, Cambridge CB24 4FQ, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Greenwood
authors.affiliation: AIXTRON Ltd, Buckingway Business Park, Anderson Road, Swavesey, Cambridge CB24 4FQ, UK.
authors.forename: Nalin
authors.initials: N
authors.lastname: Rupesinghe
authors.affiliation: AIXTRON Ltd, Buckingway Business Park, Anderson Road, Swavesey, Cambridge CB24 4FQ, UK.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Teo
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Leinenbach
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Duebendorf, Switzerland.
authors.forename: Pierangelo
authors.initials: P
authors.lastname: Gröning
keywords: brazing; carbon nanotubes; field emission