The high thermal conductivity of graphene and few-layer graphene undergoes severe degradations through contact with the substrate. Here we show experimentally that the thermal management of a micro heater is substantially improved by introducing alternative heat-escaping channels into a graphene-based film bonded to functionalized graphene oxide through amino-silane molecules. Using a resistance temperature probe for in situ monitoring we demonstrate that the hotspot temperature was lowered by ∼28°C for a chip operating at 1,300 W cm-2. Thermal resistance probed by pulsed photothermal reflectance measurements demonstrated an improved thermal coupling due to functionalization on the graphene-graphene oxide interface. Three functionalization molecules manifest distinct interfacial thermal transport behaviour, corroborating our atomistic calculations in unveiling the role of molecular chain length and functional groups. Molecular dynamics simulations reveal that the functionalization constrains the cross-plane phonon scattering, which in turn enhances in-plane heat conduction of the bonded graphene film by recovering the long flexural phonon lifetime.
Bibliographical noteFunding Information:
The work is sponsored by EU FP7 programme 'Nanotherm' under the Grant Agreement No 318117. This work is also supported by the National Chinese Science Foundation Projects (51272153 and 61574088) and the Science and Technology Commission of Shanghai Municipality programme (12JC1403900), as well as Shanghai Education Commission programme (Shanghai University Peak Discipline Construction Project), by the Swedish Foundation for Strategic Research (SSF) Frame Project Contract No: SE13-0061 and SSF Project Contract No: EM11-0002. This work is supported by EPSRC project EP/N017188/1 and by the EU ITN MOLESCO project number 606728. We acknowledge the financial support from The Production Area of Advance programme, Chalmers University of Technology, Sweden.
© 2016, Nature Publishing Group. All rights reserved.
Copyright 2018 Elsevier B.V., All rights reserved.