title: Modifying Surface Energy of Graphene via Plasma-Based Chemical Functionalization to Tune Thermal and Electrical Transport at Metal Interfaces.
abstract: The high mobility exhibited by both supported and suspended graphene, as well as its large in-plane thermal conductivity, has generated much excitement across a variety of applications. As exciting as these properties are, one of the principal issues inhibiting the development of graphene technologies pertains to difficulties in engineering high-quality metal contacts on graphene. As device dimensions decrease, the thermal and electrical resistance at the metal/graphene interface plays a dominant role in degrading overall performance. Here we demonstrate the use of a low energy, electron-beam plasma to functionalize graphene with oxygen, fluorine, and nitrogen groups, as a method to tune the thermal and electrical transport properties across gold-single layer graphene (Au/SLG) interfaces. We find that while oxygen and nitrogen groups improve the thermal boundary conductance (hK) at the interface, their presence impairs electrical transport leading to increased contact resistance (ρC). Conversely, functionalization with fluorine has no impact on hK, yet ρC decreases with increasing coverage densities. These findings indicate exciting possibilities using plasma-based chemical functionalization to tailor the thermal and electrical transport properties of metal/2D material contacts.
authors.affiliation: †Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Foley
authors.forename: Sandra C
authors.initials: SC
authors.lastname: Hernández
authors.affiliation: †Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States.
authors.forename: John C
authors.initials: JC
authors.lastname: Duda
authors.forename: Jeremy T
authors.initials: JT
authors.lastname: Robinson
authors.forename: Scott G
authors.initials: SG
authors.lastname: Walton
authors.affiliation: †Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904, United States.
authors.forename: Patrick E
authors.initials: PE
authors.lastname: Hopkins
keywords: Graphene; contact resistivity; contacts; functionalization; thermal boundary conductance