Phase formation in Cu2ZnSnSe4 thin films deposited with multi-stage co-evaporation processes
Phase formation in Cu2ZnSnSe4 thin films deposited with multi-stage co-evaporation processes
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DOI：
10.1016/j.solmat.2013.09.043
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发表时间：
2014
影响因子：
6.9
通讯作者：
G. Kaune;S. Hartnauer;F. Syrowatka;R. Scheer
中科院分区：
文献类型：
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作者：
G. Kaune;S. Hartnauer;F. Syrowatka;R. Scheer
摘要采用原位激光光散射（LLS）和非原位表征方法研究了两步共蒸发法制备Cu 2 ZnSnSe 4（CZTSe）薄膜的过程。由于工艺条件以及固有反应，膜生长被分为不同的生长阶段，每个阶段中具有特征相形成过程。在第一阶段，在Cu、Zn、Sn和Se的供应下，仅Cu 2-x Se和ZnSe沉积在衬底上。具有几百纳米厚度的膜对于引发CZTSe形成是必要的。然后，在第二相中，CZTSe通过在ZnSe中掺入Cu和Sn而生长，而Cu 2− x Se作为第二相保留。在终止Cu蒸发的第二工艺阶段，剩余的Cu 2− x Se被消耗，薄膜化学计量从富Cu变为贫Cu。发现Mo衬底对生长过程有很大影响，Mo和CZTSe之间的有害相互作用阻碍了CZTSe的生长。在整个过程中，Cu 2− x Se相在晶粒生长过程中起着重要作用，并支持大的CZTSe晶粒的形成。
Abstract The deposition of Cu 2 ZnSnSe 4 (CZTSe) thin films with a two-stage co-evaporation process was investigated with in situ laser light scattering (LLS) and ex situ characterization methods. As a result of the process conditions as well as intrinsic reactions, the film growth is divided into distinct growth phases with characteristic phase formation processes in each phase. In a first phase, under supply of Cu, Zn, Sn and Se, only Cu 2− x Se and ZnSe are deposited on the substrate. A film with several hundred nanometer thickness is necessary to initiate the CZTSe formation. Then, in a second phase, CZTSe grows by incorporation of Cu and Sn in ZnSe while Cu 2− x Se remains as secondary phase. In the second process stage with terminated Cu evaporation, the remaining Cu 2− x Se is consumed and the film stoichiometry turns from Cu-rich to Cu-poor. A substantial influence on the growth process is found for the Mo substrate, CZTSe growth is hindered by a detrimental interaction between Mo and CZTSe. During the whole process, the Cu 2− x Se phase plays an important role in the grain growth process and supports the formation of large CZTSe grains.