论文标题
通过Optothermal Raman光谱测量的单个锗纳米线的温度依赖性热电导率
Temperature-dependent thermal conductivity of a single Germanium nanowire measured by Optothermal Raman Spectroscopy
论文作者
论文摘要
我们使用Optothermal Raman光谱法研究了单个GE纳米线（NW）中温度依赖的热导率K（t），该光谱光谱利用拉曼线的温度依赖性作为温度的局部探针。该实验是从300 K到700 K以上进行的，温度范围很少探索单个NWS的热导率。 GE NWS的热导率（通过蒸气液体固体机理生长）在室温附近，直径在50至110 nm之间的1.8至4.2 W/m.k的范围内。发现在给定温度下的热导率遵循对NW直径的线性依赖性，这表明k（t）的低幅度是通过从NWS表面扩散的声子从NWS表面散射的，从而从其整体值严重降低了它。 k（t）显示了大约1/t的行为，这是由umklapp过程产生的。已经讨论了由选择性测量和减轻它们的方法引起的误差的定量估计。我们还建议使用上述观测值估算GE和SI NW的热导率的快速方法。
We investigate temperature dependent thermal conductivity k(T) in a single Ge nanowire (NW) using Optothermal Raman Spectroscopy which utilizes the temperature dependence of Raman lines as a local probe for temperature. The experiment was done from 300 K to above 700 K, a temperature range in which thermal conductivity of single NWs has been explored rarely. The thermal conductivity of Ge NWs (grown by vapor liquid solid mechanism), at around room temperature were observed to lie in the range 1.8 to 4.2 W/m.K for diameters between 50 to 110 nm. The thermal conductivity at a given temperature was found to follow a linear dependence on NW diameter, suggesting that the low magnitude of k(T) is determined by diffused scattering of phonons from the surface of NWs that reduces it severely from its bulk value. k(T) shows approximately 1/T behavior which arises from the Umklapp processes. The quantitative estimation of errors arising from the Optothermal measurement and methods to mitigate them has been discussed. We also suggest a quick way to estimate approximately the thermal conductivity of Ge and Si NWs using the above observations.
