中文摘要：

二维层状半导体材料,尤其是少数原子层时,其光电性质与晶格结构密切相关,采用合适的表征方法是关键。本文通过使用机械剥离的方法,得到了不同层数的二硒化锡,并利用光学二次谐波和拉曼光谱的表征研究了其晶体结构的性质。通过二次谐波准确确定了二硒化锡的晶轴,分析了厚度对二次谐波的影响,为确定材料的晶格结构提供了一种纯光学的手段,同时为发现二硒化锡其他非线性光学性质提供了可能性。通过拉曼光谱,发现二硒化锡层间振动模式对厚度和温度变化均较为敏感,表明二硒化锡可应用于大范围内温度的原位监测。

英文摘要：

The photoelectric properties of two-dimensional layered semiconductor materials, especially for those with a few atomic layers, are closely related to their crystal structures. Thus, the critical question is to select the proper characterization. In this article, the tin diselenide with different layers has been obtained by means of mechanical exfoliation, and the characteristics of the crystal structure have been studied by optical second harmonic generation and Raman spectrum. By using second harmonic generation, the crystal axis of tin diselenide was confirmed accurately and the effect of different thickness on second harmonic generation was analyzed, providing a purely optical method of determining the orientation of crystallographic axes, as well as offering the possibility to discover other nonlinear optical properties of tin diselenide. By Raman spectroscopy, it is found that the interlayer vibration mode was sensitive to the changes of thickness and temperature, thus tin diselenide could be applied to the temperature detection in situ within a large range.