title: In-Plane Thermal Conductivity of Polycrystalline Chemical Vapor Deposition Graphene with Controlled Grain Sizes.
abstract: Manipulation of the chemical vapor deposition graphene synthesis conditions, such as operating P, T, heating/cooling time intervals, and precursor gas concentration ratios (CH4/H2), allowed for synthesis of polycrystalline single-layered graphene with controlled grain sizes. The graphene samples were then suspended on 8 μm diameter patterned holes on a silicon-nitride (Si3N4) substrate, and the in-plane thermal conductivities k(T) for 320 K < T < 510 K were measured to be 2660-1230, 1890-1020, and 680-340 W/m·K for average grain sizes of 4.1, 2.2, and 0.5 μm, respectively, using an opto-thermal Raman technique. Fitting of these data by a simple linear chain model of polycrystalline thermal transport determined k = 5500-1980 W/m·K for single-crystal graphene for the same temperature range above; thus, significant reduction of k was achieved when the grain size was decreased from infinite down to 0.5 μm. Furthermore, detailed elaborations were performed to assess the measurement reliability of k by addressing the hole-edge boundary condition, and the air-convection/radiation losses from the graphene surface.
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.
authors.forename: Woomin
authors.initials: W
authors.lastname: Lee
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.|Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Kenneth David
authors.identifier: 0000-0001-5360-1764
authors.initials: KD
authors.lastname: Kihm
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.
authors.forename: Hong Goo
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Seungha
authors.initials: S
authors.lastname: Shin
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.
authors.forename: Changhyuk
authors.initials: C
authors.lastname: Lee
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Park
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.
authors.forename: Sosan
authors.initials: S
authors.lastname: Cheon
authors.affiliation: Department of Mechanical Engineering, Korea University , Seoul 136-713, Republic of Korea.
authors.forename: Oh Myoung
authors.initials: OM
authors.lastname: Kwon
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.
authors.forename: Gyumin
authors.initials: G
authors.lastname: Lim
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University , Seoul 151-744, Republic of Korea.
authors.forename: Woorim
authors.initials: W
authors.lastname: Lee
keywords: CVD; Graphene; grain size effect; thermal conductivity