层状WS2的拉曼张量

Raman tensor of layered WS2

为完善范德瓦尔斯层状材料有关于拉曼张量的基本信息,本文采用角分辨偏振拉曼光谱对二硫化钨的拉曼张量进行研究.根据拉曼选择定则,我们分析了角分辨拉曼光谱与偏振的依赖关系,并结合实验结果获得了面内和面外各振动模式的拉曼张量元和与张量元对应的微分极化率等信息.实验结果表明,截面测试得到的拉曼强度具有偏振依赖性,其中沿c轴振动的A1g模式引起的微分极化率明显大于E1g和E2g模式,并且A1g模式自身在沿c轴的极化率也较沿a轴或b轴的大.这种通过角分辨偏振拉曼光谱研究拉曼张量的方法对其他范德瓦尔斯层状材料具有普遍性.

Recently,van der Waals layered materials,such as MoS2,WS2,MoSe2 and WSe2,have attracted extensive attention due to their unique properties and potential applications in(optoelectronic)electronic devices[1].Similar to graphene,the atoms of van der Waals materials in the layer are connected by covalent bonds,and the van der Waals’force is applied between the layers[2].However,compared with graphene,van der Waals materials exhibit more excellent performance in sensors.