We recently showed that silicon heterojunction solar cell with MoOx-based hole-selective contact could reach 23.5% in efficiency with MoOx layers of 4 nm. Such thin MoOx layer enables a considerable current-density gain of over 1 mA/cm2 compared to the use of p-type amorphous silicon, and outperforms thicker MoOx layers. In this article, we investigated the impact of the MoOx hole-selective layer for thickness between 0 and 4 nm. Based on optoelectrical characterization of the device at various processing stage, we discuss the optical and electrical effects of such variation on the solar-cell performances. We notably identify a loss of passivation and selectivity for MoOx films thinner than 4 nm, that we link to a reduced work-function for such thin MoOx films. We confirm experimentally that the optimal MoOx thickness is around 4 nm, yet evidence that close to 0.5 mA/cm2 is still parasitically absorbed in such a thin layer.

中文翻译：

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使用超薄 MoOxHole 选择性接触的硅异质结太阳能电池的性能限制和分析


我们最近证明，采用 MoOx 基空穴选择性接触的硅异质结太阳能电池，MoOx 层厚度为 4 nm 时，效率可达到 23.5%。与使用 p 型非晶硅相比，如此薄的 MoOx 层可实现超过 1 mA/cm2 的相当大的电流密度增益，并且性能优于较厚的 MoOx 层。在本文中，我们研究了厚度在 0 至 4 nm 之间的 MoOx 空穴选择性层的影响。基于器件在不同处理阶段的光电特性，我们讨论了这种变化对太阳能电池性能的光学和电学影响。我们特别发现厚度小于 4 nm 的 MoOx 薄膜会失去钝化和选择性，这与此类薄 MoOx 薄膜的功函数降低有关。我们通过实验证实，最佳 MoOx 厚度约为 4 nm，但有证据表明，在如此薄的层中，接近 0.5 mA/cm2 的电流仍然被寄生吸收。