【作者】 黄海；

【导师】 吴晓宏；

【作者基本信息】 哈尔滨工业大学 ， 物理化学， 2012， 硕士

【摘要】 通过研究比较国内外单晶硅表面陷光结构制备的研究现状，发现黑硅是一种新型的高太阳吸收率的材料，黑硅具有多孔结构，在较宽波长范围对太阳光都能达到很好的吸收效果，即良好的广谱吸收性能，在光电领域具有十分重要的应用前景。采用化学腐蚀法来制备黑硅，研究黑硅的微观形貌对太阳吸收率的影响，同时分析腐蚀机理，陷光机理，贵金属的催化机理等。利用AFM、SEM、XRF、紫外可见吸收（透射）谱仪及半导体参数测试仪等测试方法，对黑硅的反射率、表面形貌、表面成分、剖面结构以及电学参数等进行表征。结果表明：采用以氯金酸为催化剂，双氧水为氧化剂，氢氟酸为络合剂，水为缓释剂，在超声波辅助作用下腐蚀单晶硅，得到了黑硅。通过观察不同工艺参数（超声、腐蚀时间和腐蚀温度）下黑硅的表面形貌，研究多孔结构对黑硅吸收率的影响，发现当多孔结构的高径比为0.6时，所得黑硅太阳吸收率为98.874%，且在300-800nm可见光区的反射率降低到了1%，其电学性能也表现出比较优异的性能，转化效率达到了15.18%。并对腐蚀过程中的机理进行了分析，单晶硅在腐蚀过程中，以化学吸附在表面的金纳米粒子为活性点，在催化剂下方及周围发生腐蚀反应，生成H₂SiF6和H₂，从而将表面的硅移走，形成多孔结构，多孔结构有利于增加二次反射，提高太阳吸收率。在节约成本的前提下，进行了催化剂优化研究，研究发现采用硝酸银代替氯金酸，采用KOH/IPA为腐蚀液，对单晶硅进行二次腐蚀，构筑多孔-金字塔结构，在金字塔上形成的多孔结构使得黑硅对于短波光的反应更为灵敏，所得金字塔结构黑硅的太阳吸收率为97.956%，转化效率为13.34%。这两种体系都大幅提高了单晶硅的太阳吸收率及转化效率。更多还原

【Abstract】 By comparing the current researches on the preparation of the light trappingstructure on the silicon surface home and abroad, we found that black silicon is anew material with high solar absorption rate, black silicon achieve good sunlightabsorption effect in a wide range of wavelength, we call it good broad-spectrumabsorption property, so it has very important applications in the photovoltaic sectoraera.Black silicon is prepared by chemical etching method, study the influence ofmorphology to the absorption rate of black silicon and etching mechanism, lighttrapping mechanism as well as precious metal catalytic mechanism. The reflectivityof black silicon, surface morphology, surface composition, section structure,electrical parameters and other properties of the silicon wafer with AFM, SEM, XRF,UV-visible absorption （transmission） spectrometer, semiconductor parametric testerand other testing tools.The results indicate: with HAuCl₄as the catalyst, H₂O2as the oxidant, HF as thecomplexing agent, H₂O as the release agent, the process parameters of ultrasonicassisted etching of monocrystalline silicon is finally known.By observing the surfacemorphology of black silicon in different parameters （ultrasonic, etching time andtemperature）, we study the influence of porous structure to the absorption rate ofblack silicon. The results shows that when the height to diameter ratio of the porousstructure is0.6, the highest absorption rate reaches98.874%, which shows a goodperformance in the visible region in300-800nm that the reflectivity reduced to1%.The etching mechanism in the process is also analyzed, the etching reaction isprocess under and around the gold nanoparticles which as the active point, H₂SiF6and H₂is generated, thus the removal of the surface of the silicon forms porousstructure which increase the secondary reflective to improve the solar absorption.The electrical properties also showed excellent performance which the conversionefficiency reaches15.18%. The catalysts were optimized under the premise of costsavings, using AgNO₃instead of HAuCl₄, etching monocrystalline silicon twice tobuild porous–pyramid structure by using KOH/IPA as the etching solution, Theformation of porous structure on the pyramid makes the black silicon moreresponsive to short-wave light. The solar absorptance of black silicon is97.956%andthe conversion efficiency is13.34%. Both systems have a substantial increase in the solar absorption rate and conversion efficiency of monocrystalline silicon.更多还原