Extended defects such as stacking faults and anti-site domain boundaries can perturb the band edges in Cu2ZnSnS4 and Cu2ZnSnSe4, acting as a weak electron barrier or a source for electron capture, respectively. In order to find ways to prohibit the formation of planar defects, we investigated the effect of chemical substitution on the stability of the intrinsic stacking fault and metastable polytypes and analyzed their electrical properties. Substitution of Ag for Cu makes stacking faults less stable, whereas the other substitutions (Cd and Ge) promote their formation. Ge substitution has no effect on the electron barrier of the intrinsic stacking fault, but Cd substitution reduces the barrier energy, and Ag substitution enhances electron capture by the stacking fault. While Cd substitution stabilizes the stannite structure, chemical substitutions make the primitive-mixed CuAu structure less stable with respect to the ground-state kesterite structure.
Bibliographical noteFunding Information:
We thank Gilles Dennler for his constructive suggestions. J.-S.P. thanks the Royal Society for a Shooter International Fellowship. This project has received funding from the European H2020 Framework Programme for research, technological development, and demonstration under Grant Agreement No. 720907. See http://www.starcell.eu. Via our membership of the UK’s HPC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202), this work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk). We are grateful to the UK Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/ P020194/1). The primary data for this article is available in a repository at https://doi.org/10.5281/zenodo.1453381.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)