Saniz R, Bekaert J, Partoens B, Lamoen D
CMT, Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium.
Phys Chem Chem Phys. 2017 Jun 7;19(22):14770-14780. doi: 10.1039/c7cp02033c.
We report on a first-principles study of the structural and electronic properties of a Σ3 (112) grain boundary model in CuInSe. The study focuses on a coherent, stoichiometry preserving, cation-Se terminated grain boundary, addressing the properties of the grain boundary as such, as well as the effect of well known defects in CuInSe. We show that in spite of its apparent simplicity, such a grain boundary exhibits a very rich phenomenology, providing an explanation for several of the experimentally observed properties of grain boundaries in CuInSe thin films. In particular, we show that the combined effect of Cu vacancies and cation antisites can result in the observed Cu depletion with no In enrichment at the grain boundaries. Furthermore, Cu vacancies are unlikely to produce a hole barrier at the grain boundaries, but Na may indeed have such an effect. We find that Na-on-Cu defects will tend to form abundantly at the grain boundaries, and can provide a mechanism for the carrier depletion and/or type inversion experimentally reported.
我们报道了对铜铟硒中一个Σ3（112）晶界模型的结构和电子性质的第一性原理研究。该研究聚焦于一个连贯的、保持化学计量比的、阳离子硒终止的晶界，探讨了此类晶界的性质以及铜铟硒中已知缺陷的影响。我们表明，尽管其表面看似简单，但这样一个晶界展现出非常丰富的现象学，为铜铟硒薄膜中晶界的一些实验观测性质提供了解释。特别地，我们表明铜空位和阳离子反位的综合作用可导致在晶界处观察到的铜耗尽而没有铟富集。此外，铜空位不太可能在晶界处产生空穴势垒，但钠可能确实有这样的作用。我们发现钠替代铜缺陷倾向于在晶界处大量形成，并可为实验报道的载流子耗尽和/或类型反转提供一种机制。
