Differential multi-probe thermal transport measurements of multi-walled carbon nanotubes grown by chemical vapor deposition
Differential multi-probe thermal transport measurements of multi-walled carbon nanotubes grown by chemical vapor deposition
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DOI：
10.1016/j.ijheatmasstransfer.2023.124535
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发表时间：
2023-02
影响因子：
5.2
通讯作者：
Qi-jin Jia;Yuanyuan Zhou;Xun Li;L. Lindsay;Li Shi
中科院分区：
文献类型：
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作者：
Qi-jin Jia;Yuanyuan Zhou;Xun Li;L. Lindsay;Li Shi
碳纳米管(CNT)是一种准一维纳米结构，既表现出潜在的热管理应用的高热导率，又表现出有趣的低维声子输运现象。与理论计算碳纳米管晶格导热系数的进展相比，碳纳米管的热输运测量一直受到拉曼测温技术温度敏感性差或灵敏的双探头电阻测温存在接触热阻误差的限制。在这里，我们报告了多探头测量单个多壁碳纳米管样品的固有热导率的进展，这些样品从生长衬底转移到测量设备上。这种多探针法直接测量了样品-温度计的界面热阻，并用来模拟接触样品段的温度分布。详细的温度分布有助于消除获得的悬浮样段导热系数中的接触热阻误差。建立了差动电热桥测量方法，提高了测量的信噪比，降低了40%以上的测量不确定度。同一MWCNT样品的多个悬浮段的热阻随长度的增加几乎呈线性增加，表明这些MWCNT样品中的声子-缺陷散射是扩散声子输运的结果。测得的导热系数随温度升高而增大，对于9壁多壁碳纳米管，其导热系数在室温下可达390W±220W m−1K−1。对测量结果的理论分析表明，亚微米声子平均自由程是由于晶界等扩展缺陷引起的非本征声子散射所致。由于电子束的损伤和碳纳米管样品的表面污染，所获得的导热系数降低了3倍。
Carbon nanotubes (CNTs) are quasi-one dimensional nanostructures that display both high thermal conductivity for potential thermal management applications and intriguing low-dimensional phonon transport phenomena. In comparison to the advances made in the theoretical calculation of the lattice thermal conductivity of CNTs, thermal transport measurements of CNTs have been limited by either the poor temperature sensitivity of Raman thermometry technique or the presence of contact thermal resistance errors in sensitive two-probe resistance thermometry measurements. Here we report advances in a multi-probe measurement of the intrinsic thermal conductivity of individual multi-walled CNT samples that are transferred from the growth substrate onto the measurement device. The sample-thermometer thermal interface resistance is directly measured by this multi-probe method and used to model the temperature distribution along the contacted sample segment. The detailed temperature profile helps to eliminate the contact thermal resistance error in the obtained thermal conductivity of the suspended sample segment. A differential electro-thermal bridge measurement method is established to enhance the signal-to-noise ratio and reduce the measurement uncertainty by over 40%. The obtained thermal resistances of multiple suspended segments of the same MWCNT samples increase nearly linearly with increasing length, revealing diffusive phonon transport as a result of phonon-defect scattering in these MWCNT samples. The measured thermal conductivity increases with temperature and reaches up to 390 ± 20 W m−1K−1at room temperature for a 9-walled MWCNT. Theoretical analysis of the measurement results suggests submicron phonon mean free paths due to extrinsic phonon scattering by extended defects such as grain boundaries. The obtained thermal conductivity is decreased by a factor of 3 upon electron beam damage and surface contamination of the CNT sample.