Black silicon (B-Si) has been extensively applied in the photovoltaic field for its prominent light-trapping feature, but its large surface area also brings plenty of structural defects. In this article, a postetching treatment by using acid mixed solution consisted of HNO3/HF/H2O was adopted to balance the tradeoff between optical gain and electrical losses on metal-catalyzed chemical etching B-Si surfaces. We studied the effect of etching time on the reflectance and surface passivation of B-Si on polished and pyramid textured silicon substrates. The result shows that compared with the NaOH postetching applied in the industrial product line, the acid mixed solution could improve the surface passivation and low reflectance within the etching time of 3 min. Moreover, on the base of industrial anisotropic NaOH etch procedure, within etching time of 2 min, the reflectance and Seff decreased by 2.93% and 36.5 cm/s respectively. This fast and combined postetching treatment is a potential industrial method to obtain low reflectance and surface recombination loss.

中文翻译：

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黑硅表面钝化表面结构的改进

黑硅（B-Si）以其突出的光捕获特性在光伏领域得到了广泛的应用，但其大的表面积也带来了大量的结构缺陷。在本文中，采用由 HNO3/HF/H2O 组成的酸混合溶液进行后蚀刻处理，以平衡金属催化化学蚀刻 B-Si 表面的光增益和电损耗之间的权衡。我们研究了蚀刻时间对抛光和金字塔纹理的硅衬底上 B-Si 的反射率和表面钝化的影响。结果表明，与工业生产线采用的NaOH后蚀刻相比，酸混合溶液在3min的蚀刻时间内可以改善表面钝化和低反射率。此外，在工业各向异性氢氧化钠蚀刻工艺的基础上，在 2 分钟的蚀刻时间内，反射率和 Seff 分别下降了 2.93% 和 36.5 cm/s。这种快速且组合的后蚀刻处理是获得低反射率和表面复合损失的潜在工业方法。