SnSxSe2-x单晶纳米片的可控制备与表征

锡二硫族化合物可以通过改变硫和硒的含量来连续调控三元合金材料的带隙、载流子浓度等物理化学性质,在电子和光电子器件应用上具有巨大的潜力。本文采用化学气相沉积(CVD)技术可控地制备了不同元素组分的SnS_xSe_2-x(x=0,0.2,0.5,0.8,1.0,1.2,1.5,1.8,2.0)单晶纳米片。采用扫描电子显微镜(SEM)、原子力显微镜(AFM)、能量色散X射线光谱(EDS)、透射电子显微镜(TEM)以及拉曼光谱等手段对SnS_xSe_2-x纳米片进行了综合表征。结果表明本方法成功实现了元素百分比可调的SnS_xSe_2-x单晶纳米片的可控制备。重点研究了依赖于元素百分比的SnS_xSe_2-x的拉曼特征谱,实验结果与基于密度泛函理论(DFT)的第一性原理计算得到的SnS_xSe_2-x的拉曼仿真谱高度吻合,理论计算结果较好地诠释了实验拉曼光谱发生变化的原因。本研究提供了一种元素百分比可调的三元SnS_xSe_2-x单晶纳米片的可控制备方法,同时对锡二硫族化合物的明确、无损识别提供了方案。

Controllable Preparation and Characterization of SnSxSe2-x Single Crystal Nanosheets

The band gap and carrier concentration of ternary tin dichalcogenides can be continuously controlled by changing the sulfur and selenium contents, which has large application potential in electric and photoelectric devices. In this paper, SnS_xSe_2-x (x=0, 0.2, 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, 2.0) single crystal nanosheets were controllably prepared by chemical vapor deposition (CVD) technique. The prepared SnS_xSe_2-x nanosheets were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. The results prove the controllable preparation of SnS_xSe_2-x nanosheets with adjustable elemental percentages in high monocrystalline quality. The elemental percentage dependence of the Raman spectroscopy from SnS_xSe_2-x nanosheets were especially studied, and the experimental results are well consistent to the simulation results by first-principles calculation based on the density functional theory. This study provides a reliable method for the preparation of ternary SnS_xSe_2-x single crystal nanosheets with adjustable elemental percentages. A definite and nondestructive method for the characterization of ternary tin dichalcogenides is also proposed.