In-Plane Thermal Conductivity of Polycrystalline Chemical Vapor Deposition Graphene with Controlled Grain Sizes
In-Plane Thermal Conductivity of Polycrystalline Chemical Vapor Deposition Graphene with Controlled Grain Sizes
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可控晶粒尺寸的多晶CVD石墨烯的面内热导率
DOI：
10.1021/acs.nanolett.6b05269
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发表时间：
2017-04-01
期刊：
影响因子：
10.8
通讯作者：
Lee, Woorim
中科院分区：
文献类型：
--
作者：
Lee, Woomin;Kihm, Kenneth David;Lee, Woorim
控制化学气相沉积石墨烯的合成条件，如操作P、T、加热/冷却时间间隔和前驱体气体浓度比（CH4/H-2），可以合成具有可控晶粒尺寸的多晶单层石墨烯。然后将石墨烯样品悬浮在氮化硅（Si3N4）衬底上直径为8 μ m的图案孔上，利用光热拉曼技术测量了320 k < T < 510 k时的面内热导率k(T)分别为2660-1230、1890-1020和680-340 W/m，平均晶粒尺寸分别为4.1、2.2和0.5 μ m。用多晶热输运的简单线性链模型拟合这些数据，确定k = 5500-1980 W/m，单晶石墨烯在相同温度范围内的中心点k；因此，当晶粒尺寸从无限大减小到0.5 μ m时，k值显著降低。此外，通过解决空穴边缘边界条件和石墨烯表面的空气对流/辐射损失，进行了详细的阐述，以评估k测量的可靠性。
Manipulation of the chemical vapor deposition graphene synthesis conditions, such as operating P, T, heating/cooling time intervals, and precursor gas concentration ratios (CH4/H-2), allowed for synthesis of polycrystalline single layered graphene with controlled grain sizes. The graphene samples were then suspended on 8 mu m 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 center dot K for average grain sizes of 4.1, 2.2, and 0.5 mu m, 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 center dot 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 mu m. Furthermore, detailed elaborations were performed to assess the measurement reliability of k by addressing the hole-edge boundary condition, and the airconvection/radiation losses from the graphene surface.