title: Activating "Invisible" Glue: Using Electron Beam for Enhancement of Interfacial Properties of Graphene-Metal Contact.
abstract: Interfacial contact of two-dimensional graphene with three-dimensional metal electrodes is crucial to engineering high-performance graphene-based nanodevices with superior performance. Here, we report on the development of a rapid "nanowelding" method for enhancing properties of interface to graphene buried under metal electrodes using a focused electron beam induced deposition (FEBID). High energy electron irradiation activates two-dimensional graphene structure by generation of structural defects at the interface to metal contacts with subsequent strong bonding via FEBID of an atomically thin graphitic interlayer formed by low energy secondary electron-assisted dissociation of entrapped hydrocarbon contaminants. Comprehensive investigation is conducted to demonstrate formation of the FEBID graphitic interlayer and its impact on contact properties of graphene devices achieved via strong electromechanical coupling at graphene-metal interfaces. Reduction of the device electrical resistance by ∼50% at a Dirac point and by ∼30% at the gate voltage far from the Dirac point is obtained with concurrent improvement in thermomechanical reliability of the contact interface. Importantly, the process is rapid and has an excellent insertion potential into a conventional fabrication workflow of graphene-based nanodevices through single-step postprocessing modification of interfacial properties at the buried heterogeneous contact.
authors.forename: Songkil
authors.initials: S
authors.lastname: Kim
authors.forename: Michael
authors.initials: M
authors.lastname: Russell
authors.forename: Dhaval D
authors.initials: DD
authors.lastname: Kulkarni
authors.forename: Mathias
authors.initials: M
authors.lastname: Henry
authors.affiliation: Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson AFB, Ohio 45433-7707, United States.
authors.forename: Steve
authors.initials: S
authors.lastname: Kim
authors.affiliation: Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson AFB, Ohio 45433-7707, United States.
authors.forename: Rajesh R
authors.initials: RR
authors.lastname: Naik
authors.affiliation: Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson AFB, Ohio 45433-7707, United States.
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Voevodin
authors.forename: Seung Soon
authors.initials: SS
authors.lastname: Jang
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Tsukruk
authors.forename: Andrei G
authors.initials: AG
authors.lastname: Fedorov
mesh_terms: D003300:Copper / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D004583:Electrons; D006108:Graphite / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D013499:Surface Properties; D014173:Transistors, Electronic
chemical_list: D006108:Graphite; D003300:Copper
keywords: focused electron beam induced deposition (FEBID); graphene; graphitic interlayer; heterogeneous contact; nanowelding