ABSTRACT

First-principles calculations were performed jointly with muon-spin (μSR) spectroscopy experiments in order to examine the electrical activity of hydrogen in mixed-cation chalcopyrite Cu(In${}_{1-x}$,Ga${}_x$)Se${}_2$ (CIGS) alloys and other related compounds commonly used as absorbers in solar-cell technology. The study targeted the range of Ga concentrations most relevant in typical solar cells. By means of a hybrid-functional approach the charge-transition levels of hydrogen were determined and the evolution of the defect pinning level, E(+/–), was monitored as a function of the Ga content. The use of E(+/–) as a metric of the charge-neutrality level allowed the alignment of band structures, thus providing the band offsets between the CuInSe${}_2$ compound and the CIGS alloys. The μSR measurements in both thin-film and bulk CIGS materials confirmed that the positively charged state is the thermodynamically stable configuration of hydrogen for p-type conditions. The interpretation of the μSR data further addressed the existence of a metastable quasi-atomic neutral configuration that was resolved from the calculations and led to a formation model for muon implantation.

摘要

第一原理计算用μ介子-自旋（共同执行μ SR）为了检查在混合阳离子黄铜矿铜氢的电活动光谱实验（在${}_{1-X}$,Ga${}_X$)硒${}_2$(CIGS) 合金和其他相关化合物，通常用作太阳能电池技术中的吸收剂。该研究针对典型太阳能电池中最相关的 Ga 浓度范围。通过混合功能方法，确定了氢的电荷转移能级，并监测缺陷钉扎能级 E(+/–) 的演变作为 Ga 含量的函数。使用 E(+/–) 作为电荷中性水平的度量允许带结构的对齐，从而提供 CuInSe 之间的带偏移${}_2$化合物和 CIGS 合金。薄膜和块状 CIGS 材料中的μ SR 测量证实，带正电荷的状态是 p 型条件下氢的热力学稳定构型。μ SR 数据的解释进一步解决了亚稳态准原子中性构型的存在，该构型从计算中得到解决，并导致 μ 子注入的形成模型。