The black silicon structure has excellent trapping performance, which can effectively reduce the loss of light on the surface of the solar cell. It is the key research project of the current photovoltaic industry. In this article, Ag/Cu diatom two step metal assisted chemical etching (MACE) method was adopt to prepare the high efficient single crystal black silicon trapping structure by adjusting the molar ratio of Ag/Cu, the etching temperature, etching time and the concentration of H2O2. The formation mechanism of black silicon structure and its influence on the reflectivity of silicon wafer surface was systematicly studied. The surface morphology of the samples was observed by field emission scanning electron microscopy and the diffuse reflectance spectra of the samples were measured by spectrophotometer. The results show that uniform and dense nano column structures are prepared when the molar ratio of Ag/Cu is 1/10, the etching temperature is 60 ℃, the etching time is 30 s and the concentration of H2O2is 0.6 mol/L. The etching depth is about 2.09 μm, etching aperture is 55-80 nm, and the average reflectivity of the surface is only 1.45% (200-1100 nm). It not only reduces the amount of AgNO3, saves the cost of production, but also achieves the structure of black silicon with excellent trapping performance.%黑硅结构具有优异的陷光性能,能够有效减少太阳能电池片表面的光学损耗,是目前光伏产业的重点研究项目.本文采用Ag/Cu双原子两步金属辅助化学刻蚀(MACE)工艺,通过调节Ag/Cu摩尔比、刻蚀温度、刻蚀时间以及 H2O2的浓度制备出了高效的单晶黑硅陷光结构,并系统研究了黑硅结构的形成机理及其对硅片表面反射率的影响规律.利用场发射扫描电镜观察了样品的表面形貌,利用分光光度计测试了样品表面的漫反射光谱.结果表明,当Ag/Cu摩尔比为1/10,刻蚀温度为60 ℃,刻蚀时间为30 s,H2O2的浓度为0.6 mol/L时,制备得到了均匀分布、密集排列的纳米柱结构,刻蚀深度约为2.09 μm,刻蚀孔径为55~80 nm,表面的平均反射率仅为1.45%(200~1100 nm).降低了AgNO3的用量,节约了生成成本,又获得了陷光性能优异的黑硅结构.
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