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测试分析了光照强度和掺杂浓度对n型硅电极电化学特性的影响。采用电化学阳极腐蚀法在光照辅助下制备多孔硅(PS),通过扫描电镜研究掺杂浓度对PS表面微观形貌的影响,通过积分球测试仪测试研究了PS对光的反射率。结果表明,对于n型硅,光照是激发空穴的必要手段,光照强度越强,硅/电解液界面的电荷转移阻抗越小,更利于反应的进行;掺杂浓度越高,电化学极化阻力越小,促进PS孔密度增加。本实验条件下,形成的PS是微米级孔,随着掺杂浓度的增加,形成的PS孔径越小,孔深存在一个极值;电阻率为0.35Ω·cm的硅片拥有最大的孔深13μm;PS的孔结构大大提升了硅基对光子的捕获能力,相比于单晶硅,在可见-近红外范围,电阻率为0.0047Ω·cm的硅片制备的n-PS对光的反射率已经从30%降低到了5%。
The influence of light intensity and doping concentration on the electrochemical characteristics of n-type silicon electrode was analyzed. Porous silicon (PS) was prepared by electrochemical anodic etching method under light irradiation. The effect of doping concentration on the microstructure of PS surface was investigated by scanning electron microscopy. The reflectance of PS was measured by integrating sphere tester. The results show that for n-type silicon, illumination is an essential means to excite holes. The stronger the light intensity is, the smaller the charge transfer resistance at the silicon / electrolyte interface is and the more conducive to the reaction. The higher the doping concentration, the higher the electrochemical polarization The smaller the resistance, the increased density of PS holes. Under the experimental conditions, the formed PS is a micron-sized hole. As the doping concentration increases, the smaller the PS pore size is formed, the more the hole depth has an extreme value. The silicon wafer with a resistivity of 0.35 Ω · cm has the largest hole depth 13 μm; the pore structure of PS greatly enhances the silicon-based capture of photons. Compared with monocrystalline silicon, the reflection of light by n-PS prepared from silicon wafer with a resistivity of 0.0047 Ω · cm in the visible-near-infrared range The rate has been reduced from 30% to 5%.