We have systematically investigated the temperature dependent Raman spectroscopy behavior of a few layered MoS2 and WS2 nanosheets synthesized using simple hydrothermal method. Our result reveals A1g and E12g modes soften as temperature increases from 77 K to 623 K. This behavior can be explained in terms of a double resonance process which is active in single- and few layer thick nanosheets. The frequency shifts and peak broadening can provide unambiguous, nondestructive, and accurate information of a few layered MoS2 and WS2. This mechanism can also be applicable in characterizing the structural, optical, electronic, and vibrational properties of other emerging layered materials.

中文翻译：

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化学衍生的少层 MoS2 和 WS2 纳米片的温度相关拉曼光谱

我们系统地研究了一些使用简单水热法合成的层状 MoS2 和 WS2 纳米片的温度相关拉曼光谱行为。我们的结果表明，随着温度从 77 K 增加到 623 K，A1g 和 E12g 模式会软化。这种行为可以用双共振过程来解释，该过程在单层和几层厚的纳米片中很活跃。频移和峰展宽可以提供一些层状 MoS2 和 WS2 的明确、无损和准确的信息。这种机制也适用于表征其他新兴层状材料的结构、光学、电子和振动特性。