Recent breakthroughs in Cu(In,Ga)Se₂ (CIGS) thin film solar cell energy conversion efficiency are related to the application of a potassium fluoride post‐deposition treatment (KF‐PDT) to the completed absorber. Using X‐ray photoelectron spectroscopy and Raman scattering, we compare CIGS layers prior and after the KF‐PDT in the case of a deterioration and an improvement of the solar cells photovoltaic performance. The purpose is to study and model the modification of the surface in both cases and address some of the required characteristics of the absorber, grown on soda lime glass by 3‐stage process, in order to take advantage of the treatment. We show that, in both cases, KF‐PDT induces the formation of GaF₃, which is removed during the subsequent chemical bath deposition of CdS, explaining the Ga depleted absorber surface, already reported in literature. However, the presence or not of an ordered defect compound (ODC), correlated with the third stage duration during the CIGS growth, is shown to be crucial in the modifications of the surface induced by the treatment. When an ODC is present prior the treatment, KF‐PDT leads to the formation of a surface layer of In₂Se₃ containing K, and the photovoltaic performance of completed solar cells are improved. When no ODC is present prior KF‐PDT, no trace of K is found at the absorber surface after the treatment, copper (Cu) segregates into detrimental Cu_xSe phases, high amount of elemental Se is formed, and the photovoltaic performance are lowered. The role of the ODC during the KF‐PDT is finally discussed.

中文翻译：

---

共蒸发Cu（In，Ga）Se2薄膜太阳能电池中的KF沉积后处理：吸收体特性引起的有益或有害作用

Cu（In，Ga）Se ₂（CIGS）薄膜太阳能电池能量转换效率的最新突破与对完成的吸收器进行氟化钾后沉积处理（KF-PDT）有关。使用X射线光电子能谱和拉曼散射，我们比较了KF-PDT之前和之后的CIGS层，以了解太阳能电池光伏性能的恶化和改善情况。目的是研究和建模两种情况下的表面改性，并解决通过三步法在钠钙玻璃上生长的吸收剂的一些所需特性，以便利用这种处理方法。我们证明，在两种情况下，KF-PDT都会诱导GaF ₃的形成。在随后的化学镀CdS沉积过程中将其去除，这解释了Ga吸收体表面贫化的情况，这在文献中已有报道。但是，与CIGS生长过程中的第三阶段持续时间相关的有序缺陷化合物（ODC）的存在与否对处理引起的表面改性至关重要。当在处理之前存在ODC时，KF-PDT会导致形成含K的In ₂ Se ₃表面层，从而改善了完整太阳能电池的光伏性能。如果在KF-PDT之前没有ODC，在处理后的吸收塔表面没有发现K的痕迹，则铜（Cu）会分离成有害的Cu _x硒相，形成大量的元素硒，降低了光伏性能。最后讨论了ODF在KF-PDT中的作用。