Just Justus, Sutter-Fella Carolin M, Lützenkirchen-Hecht Dirk, Frahm Ronald, Schorr Susan, Unold Thomas
Department Structure and Dynamics of Energy Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner Platz 1, 14109 Berlin, Germany.
Phys Chem Chem Phys. 2016 Jun 21;18(23):15988-94. doi: 10.1039/c6cp00178e. Epub 2016 May 31.
Secondary phases zinc sulfide/selenide and copper sulfide in Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) thin film samples are investigated by X-ray absorption near edge structure (XANES) analysis at the chalcogen K-edges. Because of the formation of secondary phases the composition of the kesterite phase can deviate significantly from the total sample composition. For a large set of non-stoichiometric samples we find that the cation ratios of the kesterite phase never exceed Zn/Sn = 1 even for Zn-rich CZTS and CZTSe, with all excess Zn being contained in secondary phases. For CZTS the cation ratios are found to be additionally constrained by Cu/Sn ≤ 2, which means that Cu-excess always leads to the formation of CuxS secondary phases. These results give clear bounds on the Cu-rich and Zn-rich sides of the single phase region in polycrystalline CZTS/Se thin films.
通过硫属元素K边的X射线吸收近边结构（XANES）分析，研究了Cu2ZnSnS4（CZTS）和Cu2ZnSnSe4（CZTSe）薄膜样品中的次生相硫化锌/硒化物和硫化铜。由于次生相的形成，纤锌矿相的组成可能会与样品总组成有显著偏差。对于大量非化学计量比的样品，我们发现即使对于富锌的CZTS和CZTSe，纤锌矿相的阳离子比也不会超过Zn/Sn = 1，所有过量的锌都包含在次生相中。对于CZTS，发现阳离子比还受到Cu/Sn ≤ 2的限制，这意味着铜过量总是会导致形成CuxS次生相。这些结果明确了多晶CZTS/Se薄膜单相区域富铜和富锌两侧的界限。
