Beijing National Laboratory for Condensed, Matter Physics Institute of Physics, Chinese Academy of Sciences, Beijing 100190, PR China.
Small. 2012 May 7;8(9):1392-7. doi: 10.1002/smll.201101792. Epub 2012 Feb 20.
Nanoscale textured silicon and its passivation are explored by simple low-cost metal-assisted chemical etching and thermal oxidation, and large-area black silicon was fabricated both on single-crystalline Si and multicrystalline Si for solar cell applications. When the Si surface was etched by HF/AgNO(3) solution for 4 or 5 min, nanopores formed in the Si surface, 50-100 nm in diameter and 200-300 nm deep. The nanoscale textured silicon surface turns into an effective medium with a gradually varying refractive index, which leads to the low reflectivity and black appearance of the samples. Mean reflectance was reduced to as low as 2% for crystalline Si and 4% for multicrystalline Si from 300 to 1000 nm, with no antireflective (AR) coating. A black-etched multicrystalline-Si of 156 mm × 156 mm was used to fabricate a primary solar cell with no surface passivation or AR coating. Its conversion efficiency (η) was 11.5%. The cell conversion efficiency was increased greatly by using surface passivation process, which proved very useful in suppressing excess carrier recombination on the nanostructured surface. Finally, a black m-Si cell with efficiency of 15.8% was achieved by using SiO(2) and SiN(X) bilayer passivation structure, indicating that passivation plays a key role in large-scale manufacture of black silicon solar cells.
采用简单的低成本金属辅助化学刻蚀和热氧化方法探索了纳米纹理硅及其钝化，在单晶硅和多晶硅上都制备了大面积的黑硅，用于太阳能电池应用。当 Si 表面用 HF/AgNO3 溶液蚀刻 4 或 5 分钟时，Si 表面会形成纳米孔，直径为 50-100nm，深度为 200-300nm。纳米纹理硅表面变成具有渐变折射率的有效介质，导致样品的低反射率和黑色外观。未经抗反射（AR）涂层处理，晶体硅的平均反射率从 300nm 到 1000nm 降低到 2%以下，多晶硅的平均反射率从 300nm 到 1000nm 降低到 4%以下。使用 156mm×156mm 的黑色多晶硅制造了一个没有表面钝化或 AR 涂层的初级太阳能电池。其转换效率（η）为 11.5%。通过使用表面钝化工艺，大大提高了电池的转换效率，这证明了在抑制纳米结构表面上过剩载流子复合方面非常有用。最后，通过使用 SiO2 和 SiN(X)双层钝化结构，实现了效率为 15.8%的黑 m-Si 电池，表明钝化在黑硅太阳能电池的大规模制造中起着关键作用。
