title: Graphene bimetallic-like cantilevers: probing graphene/substrate interactions.
abstract: The remarkable mechanical properties of graphene, the thinnest, lightest, and strongest material in existence, are desirable in applications ranging from composite materials to sensors and actuators. Here, we demonstrate that these mechanical properties are strongly affected by the interaction with the substrate onto which graphene is deposited. By measuring the temperature-dependent deflection of graphene/substrate "bimetallic" cantilevers we determine strain, thermal expansion coefficient, and the adhesion force acting on graphene films attached to a substrate. Graphene deposited on silicon nitride (SiN(x)) is under much larger strain, ε(g) ∼ 1.5 × 10(-2), compared to graphene on gold (Au), ε(g) < 10(-3). The thermal expansion coefficient α(g) of graphene attached to SiN(x) is found to be negative, in the range from (- 5... - 1) × 10(-6)K(-1) and smaller in magnitude than α(g) of suspended graphene. We also estimate the interfacial shear strength of the graphene/SiN(x) interface to be ∼1 GPa at room temperature.
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235, United States.
authors.forename: Hiram
authors.initials: H
authors.lastname: Conley
authors.forename: Nickolay V
authors.initials: NV
authors.lastname: Lavrik
authors.forename: Dhiraj
authors.initials: D
authors.lastname: Prasai
authors.forename: Kirill I
authors.initials: KI
authors.lastname: Bolotin
mesh_terms: D055119:Elastic Modulus; D006108:Graphite / Q000737:chemistry*; D008422:Materials Testing; D008670:Metals / Q000737:chemistry*; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013314:Stress, Mechanical; D013499:Surface Properties; D013814:Thermal Conductivity
chemical_list: D008670:Metals; D006108:Graphite