Studies of compositional dependent Cu2Zn(GexSn1-x)S4 thin films prepared by sulfurizing sputtered metallic precursors
Studies of compositional dependent Cu2Zn(GexSn1-x)S4 thin films prepared by sulfurizing sputtered metallic precursors
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DOI：
10.1016/j.jallcom.2014.09.097
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发表时间：
2015-02-05
影响因子：
6.2
通讯作者：
Hao, Xiaojing
中科院分区：
文献类型：
--
作者：
Chen, Jian;Li, Wei;Hao, Xiaojing
Ge取代的Cu 2 ZnSnS 4（CZTS）薄膜在太阳能电池的制备，特别是渐变带隙太阳能电池和多结太阳能电池的制备中具有广阔的应用前景。但是，对于Cu 2 Zn（GexSn 1-x）S-4（CZTGS）合金的结构性能随合金成分x的变化规律还没有系统的研究。本文采用溅射法制备了Zn/Cu/Ge/Sn金属前驱体叠层，并对其进行硫化处理，制备了多晶CZTGS薄膜。在透射电子显微镜（TEM）系统中进行的能量色散X-射线光谱（EDS）线扫描显示在整个合成的薄膜均匀的元素分布（除了一些ZnS偏析）。X射线衍射（XRD）和拉曼光谱分析证实，通过在580 ℃下对金属叠层进行2 h的硫化，成功地获得了Cu 2 ZnSnS 4。由XRD图谱得出的CZTGS的晶格常数a和c遵循Vegard规则，即晶格常数随Ge含量（x）线性变化。拉曼光谱表明，当Sn逐渐被Ge取代时，A1模向高频移动。化学成分研究表明，x值的增加导致硫化过程中（Ge + Sn）元素的损失增加，这可以用Ge硫化物的高蒸气压来解释。通过与Ge合金化，CZTS的晶粒尺寸增大，这也导致表面粗糙。(C)2014爱思唯尔有限公司版权所有。
Ge-substituted Cu2ZnSnS4 (CZTS) thin films are promising for solar cell manufacturing, especially for graded-band-gap solar cells and multi-junction solar cells. However, there is no systematic research on the change of structural properties of Cu2Zn(GexSn1-x)S-4 (CZTGS) as the function of alloy composition x. In this work, polycrystalline CZTGS thin films were prepared by sulfurizing sputtered Zn/Cu/Ge/Sn metallic precursor stacks. Energy-dispersive X-ray spectroscopy (EDS) line scans conducted in a transmission electron microscopy (TEM) system shows uniform element distribution (except of some ZnS segregation) throughout the synthesized films. The analysis of X-ray diffraction (XRD) and Raman spectroscopy confirms that Cu2ZnSnS4 is successfully obtained by sulfurizing metallic stacks at 580 degrees C for 2 h. The lattice constants a and c of CZTGS as derived from XRD patterns follow the Vegard's rule that lattice constants vary linearly with Ge content (x). Raman spectra shows an A1 mode shift towards high frequency when Sn is gradually replaced by Ge. Chemical composition study indicates the increase in x value leads to higher (Ge + Sn) element loss during the sulfurization process, which can be explained by the high vapour pressure of Ge sulfides. By alloying with Ge, the grain size of CZTS is enlarged which also leads to a rough surface. (C) 2014 Elsevier B.V. All rights reserved.