论文标题
从2-D到准1-D的晶格转换以及去角质ZRS2和ZRSE2的声子特性
Lattice Transformation from 2-D to Quasi 1-D and Phonon Properties of Exfoliated ZrS2 and ZrSe2
论文作者
论文摘要
我们使用共焦拉曼光谱法研究了这些基于锆的材料的热性能。我们观察到了2种不同的和独特的拉曼特征，用于去角质Zrx2（其中X = S或SE）。这些拉曼模式通常取决于剥落的纳米片的形状，而不管入射激光极化如何。这两个形状分为2d-Zrx2和Quasi 1d-Zrx2。对于2d-Zrx2，拉曼模式与文献中报道的模式保持一致。但是，对于准1d-Zrx2，我们表明拉曼模式与去角质的Zrx3纳米片相同，表明从2D到Quasi-1d进行了主要的晶格转换。我们还测量了每种ZRX2形状的每种共振拉曼模式的热性能。根据我们的测量值，大多数拉曼模式都表现出与温度的线性降档相关性。但是，对于ZRS2，我们看到具有A1G模式温度的升级（BlueShift），这归因于由偶极偶联与IR活性模式引起的非谐波效应。此外，某些准1d-Zrx2的声子模式的观察到的温度依赖系数急剧不同，这可能是由准1D晶格引起的。最后，我们在2d-Zrx2和Quasi 1d-Zrx2的每个光学加热下测量声子动力学，并在Quasi 1d-Zrx2纳米片中显示声子限制。我们提取2D-ZRX2和准1D-ZRX2纳米片的每种导热率和界面导热率。我们的计算表明，与2D-ZRX2相比，准1D-ZRX2的界面热电导率较低，这可以归因于1D中的声子限制。基于我们的模型，我们显示所有ZRX2纳米片的热导率较低。我们的结果证明了ZRX2材料的非凡热能性能，使其非常适合将来的热管理策略和热电设备应用。
We investigate the thermal properties of these Zirconium based materials using confocal Raman spectroscopy. We observed 2 different and distinctive Raman signatures for exfoliated ZrX2 (where X = S or Se). These Raman modes generally depend on the shape of the exfoliated nanosheets, regardless of the incident laser polarization. These 2 shapes are divided into 2D- ZrX2 and quasi 1D- ZrX2. For 2D- ZrX2, Raman modes are in alignment with those reported in literature. However, for quasi 1D-ZrX2, we show that Raman modes are identical to exfoliated ZrX3 nanosheets, indicating a major lattice transformation from 2D to quasi-1D. We also measure thermal properties of each resonant Raman mode for each ZrX2 shape. Based on our measurements, most Raman modes exhibit a linear downshift dependence with temperature. However, for ZrS2, we see an upshift (blueshift) with temperature for A1g mode, which is attributed to non-harmonic effects caused by dipolar coupling with IR-active modes. Moreover, the observed temperature dependence coefficient for some phonon modes of quasi 1D-ZrX2 differ dramatically, which can be caused by the quasi 1D lattice. Finally, we measure phonon dynamics under optical heating for each of 2D-ZrX2 and quasi 1D-ZrX2 and show phonon confinement in quasi 1D-ZrX2 nanosheets. We extract the thermal conductivity and the interfacial thermal conductance for each of 2D-ZrX2 and quasi 1D-ZrX2 nanosheets. Our calculations indicate lower interfacial thermal conductance for quasi 1D-ZrX2 compared to 2D-ZrX2, which can be attributed to the phonon confinement in 1D. Based on our model, we show low thermal conductivity for all ZrX2 nanosheets. Our results demonstrate exceptional thermal properties for ZrX2 materials, making them ideal for future thermal management strategies and thermoelectric device applications.
