Abstract Measuring the thermal conductivity kg of supported graphene is inherently complicated due to uncertainties associated with the heat dissipation into the substrate. We innovate the use of an ultra-thin 8-nm SiO2 substrate to alleviate these uncertainties and thus improve the accuracy of optothermal Raman technique to measure kg of supported graphene. As a result, we present an extensive kg database for a wide temperature range from 325 K to 575 K. Furthermore, we have found that the thermal conductivity of supported graphene before annealing is close to that of suspended graphene at 3000 W m−1 K−1, which is attributable to graphene “suspension” lightly on the substrate roughness, and then progressively decreases over repeated thermal annealing. We elaborate on this annealing-induced kg to occur mainly because of the thermally enhanced graphene-substrate conformity and interfacial scattering by probing the Raman spectroscopic characterization of charge carrier density in graphene and the thermal expansion mismatching strain between graphene and substrate. Repeated thermal annealing also expedites the depletion of intercalated impurities to reduce the graphene-substrate separation distance, which acts to further reduces kg, ultimately to its lower bound under vacuum-annealing. Therefore, manipulating the thermo-mechanical affiliation can offer an alternative route to control the in-plane thermal conductivity of supported graphene.

中文翻译：

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石墨烯-基板整合对负载石墨烯面内热导率的影响

摘要 由于与基板散热相关的不确定性，测量负载石墨烯的热导率 kg 本身就很复杂。我们创新使用超薄 8 纳米 SiO2 衬底来减轻这些不确定性，从而提高光热拉曼技术测量负载石墨烯 kg 的准确性。因此，我们提供了一个广泛的 kg 数据库，适用于 325 K 到 575 K 的宽温度范围。此外，我们发现退火前负载石墨烯的热导率接近 3000 W m-1 K 时悬浮石墨烯的热导率-1，这归因于石墨烯轻微“悬浮”在基板粗糙度上，然后随着反复热退火逐渐降低。我们通过探测石墨烯中电荷载流子密度的拉曼光谱表征以及石墨烯和基板之间的热膨胀失配应变，详细说明了这种退火诱导的 kg 发生的主要原因是热增强的石墨烯-基板一致性和界面散射。重复的热退火还加​​速了嵌入杂质的消耗，以减少石墨烯与基板的分离距离，从而进一步降低 kg，最终在真空退火下降至其下限。因此，操纵热机械关系可以提供一种替代途径来控制负载石墨烯的面内热导率。