title: Thermal conductivity of graphene with defects induced by electron beam irradiation.
abstract: We investigate the thermal conductivity of suspended graphene as a function of the density of defects, ND, introduced in a controllable way. High-quality graphene layers are synthesized using chemical vapor deposition, transferred onto a transmission electron microscopy grid, and suspended over ∼7.5 μm size square holes. Defects are induced by irradiation of graphene with the low-energy electron beam (20 keV) and quantified by the Raman D-to-G peak intensity ratio. As the defect density changes from 2.0 × 10(10) cm(-2) to 1.8 × 10(11) cm(-2) the thermal conductivity decreases from ∼(1.8 ± 0.2) × 10(3) W mK(-1) to ∼(4.0 ± 0.2) × 10(2) W mK(-1) near room temperature. At higher defect densities, the thermal conductivity reveals an intriguing saturation-type behavior at a relatively high value of ∼400 W mK(-1). The thermal conductivity dependence on the defect density is analyzed using the Boltzmann transport equation and molecular dynamics simulations. The results are important for understanding phonon - point defect scattering in two-dimensional systems and for practical applications of graphene in thermal management.
authors.affiliation: Phonon Optimized Engineered Materials (POEM) Center and Nano-Device Laboratory (NDL), Department of Electrical and Computer Engineering, University of California - Riverside, Riverside, California 92521, USA. balandin@ece.ucr.edu.
authors.forename: Hoda
authors.initials: H
authors.lastname: Malekpour
authors.forename: Pankaj
authors.initials: P
authors.lastname: Ramnani
authors.forename: Srilok
authors.initials: S
authors.lastname: Srinivasan
authors.forename: Ganesh
authors.initials: G
authors.lastname: Balasubramanian
authors.forename: Denis L
authors.initials: DL
authors.lastname: Nika
authors.forename: Ashok
authors.initials: A
authors.lastname: Mulchandani
authors.forename: Roger K
authors.initials: RK
authors.lastname: Lake
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Balandin