Critical problems faced in Raman-based energy transport characterization of nanomaterials
Critical problems faced in Raman-based energy transport characterization of nanomaterials
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DOI：
10.1039/d2cp02126a
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发表时间：
2022-07-27
影响因子：
3.3
通讯作者：
Wang, Xinwei
中科院分区：
文献类型：
--
作者：
Wang, Ridong;Hunter, Nicholas;Wang, Xinwei
在过去的二十年里，人们对二维材料的发现、设计和合成、表征和应用进行了大量的研究。二维材料的热导率和界面热导/热阻是其应用中的两个关键性能。拉曼光谱测量光子通过光学声子的非弹性散射，可以将二维材料的温度与其周围材料的温度区分开来，具有前所未有的空间分辨率（低至原子水平）。基于拉曼的测温已经被广泛用于表征二维材料（悬浮或支撑）的导热性和界面导热/电阻。在文献中观察到非常大的数据偏差，部分原因是由于测量中未考虑的物理现象和因素。在这里，我们对基于拉曼的二维材料热表征所面临的广泛的物理问题进行了批判性的回顾，分析和观点，即界面分离，热膨胀失配引起的局部应力，光学干涉，共轭声子和热载流子输运，光声声子热不平衡，以及单层二维材料中的辐射电子-空穴复合。忽视这些问题将导致对声子输运和界面能量耦合的物理理解不合理。本文还对能量输运态解决拉曼（ET-Raman）技术进行了深入讨论，以克服这些问题，并对未来的研究挑战和需求进行了讨论。
In the last two decades, tremendous research has been conducted on the discovery, design and synthesis, characterization, and applications of two-dimensional (2D) materials. Thermal conductivity and interface thermal conductance/resistance of 2D materials are two critical properties in their applications. Raman spectroscopy, which measures the inelastic scattering of photons by optical phonons, can distinct a 2D material's temperature from its surrounding materials', featuring unprecedented spatial resolution (down to the atomic level). Raman-based thermometry has been used tremendously for characterizing the thermal conductivity of 2D materials (suspended or supported) and interface thermal conductance/resistance. Very large data deviations have been observed in literature, partly due to physical phenomena and factors not considered in measurements. Here, we provide a critical review, analysis, and perspectives about a broad spectrum of physical problems faced in Raman-based thermal characterization of 2D materials, namely interface separation, localized stress due to thermal expansion mismatch, optical interference, conjugated phonon, and hot carrier transport, optical-acoustic phonon thermal nonequilibrium, and radiative electron-hole recombination in monolayer 2D materials. Neglect of these problems will lead to a physically unreasonable understanding of phonon transport and interface energy coupling. In-depth discussions are also provided on the energy transport state-resolved Raman (ET-Raman) technique to overcome these problems and on future research challenges and needs.