MoOX has emerged as an effective hole-selective layer for Si based heterojunction solar cells on account of its high workfunction. The hole selectivity of MoOX is fundamentally different from other carrier selective films as it does not have an electron blocking energy barrier in form of conduction band offset with Si. Accordingly, much is unknown about the hole-selective nature of Si/MoOX junction with many unresolved puzzles. Here, through a combination of detailed modeling and experiments, we provide a coherent, calibrated, and comprehensive model to describe unique hole selective features of Si/MoOX junctions. The model accurately predicts the dark characteristics (ideality factor and reverse saturation current) and the open-circuit voltage of Si/MoOX based heterojunction solar cells reported in the literature. In addition, the same model anticipates the trends for solar cells with a-Si as interlayer passivation. As such this work establishes the limits of achievable VOC and its functional dependence on MoOX material parameters and, hence, could be of broad interest to enable further performance optimization of solar cells with large workfunction carrier selective layers such as V2O5 and WO3.

中文翻译：

---

揭示 Si/MoO$_X$ 异质结的空穴选择性

由于其高功函数，MoOX 已成为硅基异质结太阳能电池的有效空穴选择性层。MoOX 的空穴选择性与其他载流子选择性薄膜有着根本的不同，因为它没有以 Si 导带偏移形式的电子阻挡能垒。因此，关于 Si/MoOX 结的空穴选择性特性还有很多未解决的难题。在这里，通过详细建模和实验的结合，我们提供了一个连贯、校准和全面的模型来描述 Si/MoOX 结的独特空穴选择性特征。该模型准确预测了文献报道的Si/MoOX基异质结太阳能电池的暗特性（理想因子和反向饱和电流）和开路电压。此外，相同的模型预测了使用 a-Si 作为层间钝化的太阳能电池的趋势。因此，这项工作确定了可实现的 VOC 的限制及其对 MoOX 材料参数的功能依赖性，因此，对于具有大功函数载流子选择层（如 V2O5 和 WO3）的太阳能电池的进一步性能优化可能具有广泛的兴趣。