II–VI/Si tandem solar cells have strong potential for high efficiency at low cost by combining the two most widely used solar cell materials: silicon and cadmium telluride (CdTe). However, there are challenges with this merger, as loss of minority-carrier lifetime in the silicon bottom cell can be caused by growth of a II–VI cell on top. Silicon lifetime degradation in monolithic II–VI/Si structures is measured here on experimental samples for CdTe deposition temperatures between 400 and 500 °C, with variable In2O3:ZnO (IZO) thickness between the CdTe and silicon, and with and without CdCl2 postdeposition treatment. Results indicate that the CdCl2 treatment has the strongest effect on silicon lifetime reduction, followed by temperature and IZO thickness. Potential causes are discussed, and the effect on monolithic II–VI/Si two-junction solar cells is modeled. Remarkably, many silicon samples in the study were able to maintain >400 μs lifetimes, with some exceeding 1 ms, consistent with >30% projected efficiency in fully integrated II–VI/Si tandem solar cells.

中文翻译：

---

单片 II-VI/Si 串联太阳能电池中的硅降解

通过结合两种最广泛使用的太阳能电池材料：硅和碲化镉 (CdTe)，II-VI/Si 串联太阳能电池具有以低成本实现高效率的巨大潜力。然而，这种合并存在挑战，因为硅底部电池中少数载流子寿命的损失可能是由顶部 II-VI 电池的生长造成的。在 CdTe 沉积温度为 400 至 500 °C、CdTe 和硅之间具有可变的 In2O3:ZnO (IZO) 厚度以及有和没有 CdCl2 后沉积处理的实验样品上测量了单片 II-VI/Si 结构中的硅寿命退化. 结果表明，CdCl2 处理对硅寿命降低的影响最大，其次是温度和 IZO 厚度。讨论了潜在的原因，并对单片 II-VI/Si 双结太阳能电池的影响进行建模。值得注意的是，研究中的许多硅样品能够保持 >400 μs 的寿命，有些超过 1 ms，与完全集成的 II-VI/Si 串联太阳能电池的预计效率 >30% 一致。