title: Role of Remote Interfacial Phonon (RIP) Scattering in Heat Transport Across Graphene/SiO2Interfaces.
abstract: Heat transfer across interfaces of graphene and polar dielectrics (e.g., SiO2) could be mediated by direct phonon coupling, as well as electronic coupling with remote interfacial phonons (RIPs). To understand the relative contribution of each component, we develop a new pump-probe technique called voltage-modulated thermoreflectance (VMTR) to accurately measure the change of interfacial thermal conductance under an electrostatic field. We employed VMTR on top gates of graphene field-effect transistors and find that the thermal conductance of SiO2/graphene/SiO2interfaces increases by up to ΔG ≈ 0.8 MW m-2K-1under electrostatic fields of <0.2 V nm-1. We propose two possible explanations for the small observed ΔG. First, because the applied electrostatic field induces charge carriers in graphene, our VMTR measurements could originate from heat transfer between the charge carriers in graphene and RIPs in SiO2. Second, the increase in heat conduction could be caused by better conformity of graphene interfaces under electrostatic pressure exerted by the induced charge carriers. Regardless of the origins of the observed ΔG, our VMTR measurements establish an upper limit for heat transfer from unbiased graphene to SiO2substrates via RIP scattering; for example, only <2% of the interfacial heat transport is facilitated by RIP scattering even at a carrier concentration of ∼4 × 1012cm-2.
authors: Department of Mechanical Engineering, and Centre for Advanced 2D Materials, National University of Singapore , Singapore 119077.
authors: Yee Kan
authors: YK
authors: Koh
authors: Department of Electrical and Computer Engineering, Micro and Nanotechnology Lab, University of Illinois , Urbana, Illinois 61801, United States.
authors: Austin S
authors: AS
authors: Lyons
authors: Department of Electrical and Computer Engineering, Micro and Nanotechnology Lab, University of Illinois , Urbana, Illinois 61801, United States.|Korea Research Institute of Standards and Science , Daejeon 305-340, Republic of Korea.
authors: Myung-Ho
authors: MH
authors: Bae
authors: Department of Mechanical Engineering, and Centre for Advanced 2D Materials, National University of Singapore , Singapore 119077.
authors: Bin
authors: B
authors: Huang
authors: Department of Electrical and Computer Engineering, Micro and Nanotechnology Lab, University of Illinois , Urbana, Illinois 61801, United States.
authors: Vincent E
authors: VE
authors: Dorgan
authors: Department of Materials Science and Engineering, and Frederick Seitz Materials Research Laboratory, University of Illinois , Urbana, Illinois 61801, United States.
authors: David G
authors: DG
authors: Cahill
authors: Department of Electrical and Computer Engineering, Micro and Nanotechnology Lab, University of Illinois , Urbana, Illinois 61801, United States.|Department of Electrical Engineering and Precourt Institute for Energy, Stanford University , Stanford, California 94305, United States.
authors: Eric
authors: E
authors: Pop
keywords: Remote interfacial phonon (RIP) scattering; electrostatic control of heat conduction; electrostatic pressure; graphene interfaces; interfaces of 2D materials; interfacial thermal conductance