【作者】 郭长春；

【导师】 周艺；

【作者基本信息】 长沙理工大学 ， 应用化学， 2012， 硕士

【摘要】 当前日益严重的环境污染和能源危机，使得太阳能近年来成为研究的热点，晶体硅材料因为储量丰富和无毒性，广泛地应用于光伏产业，而最近几年多晶硅材料则成为制备太阳电池最重要的材料。多晶硅表面织构化可以减少光的损失，提高多晶太阳电池的光电转换效率。近些年，研究者采用机械刻槽，反应离子，激光刻槽和酸腐蚀织构等方法来获得具有陷光效应的多晶硅织构表面。其中酸腐蚀织构法，成本低、高效率且易于大规模制备等优点被广泛的应用到工业生产中。本文的主要的结果如下：（1）腐蚀速率随着HNO₃的比例的增加，先升高，后下降。在富HF体系下，可以获得较低的反射率的表面织构，但晶界处的腐蚀深度很深，不易于电极的印刷和电子的收集；而富HNO₃的腐蚀体系下，制备得到的织构表面反射率较高。（2）不同配比的腐蚀体系中，温度对反应速率的影响存在较大差异，低温刻蚀比常温刻蚀更具优势，应当选择在HNO₃比例相对较低的腐蚀体系（HF:HNO₃:H₂O=1:4:2）中进行，当体系温度为3℃时，刻蚀反应速率为2.6μm/min,该反应速率适合于工业生产。（3）腐蚀反应先从激活能较低处发生反应，然后逐渐形成深宽比较大的腐蚀坑，反射率逐渐达到最低；然后表面腐蚀坑开始横向发展，最后趋于平坦。酸腐蚀织构反应过程中反射率先降低，后升高，最后趋于稳定的过程。（4）在富HNO₃的腐蚀体系下，可以通过调整温度和时间，来控制腐蚀重量在一定范围，这样可以保证长时间大面积生产，后续工序可以获得稳定的织构化表面。“蚯蚓状”的腐蚀坑结构，可以兼顾太阳电池的光学和电学性能，具有最佳的转化效率。该方案已在25MW多晶硅太阳电池生产线上实施，不增加工艺难度和生产成本，适合于工业生产。更多还原

【Abstract】 Recently the increasing serious environment pollution and energy crisis prompt the rapiddevelopment of solar energy. Crystalline silicon （c-Si） is a material commonly used byterrestrial photovoltaics （PV） industry because of non-toxicity and abundance （25%of theEarth’s crust）. In recent years, the multi-crystalline silicon （mc-Si） has become one of themost important substrate materials for solar-cell applications. It is known that texturizationtechnology can reduce the reflection losses thus overall efficiencies on mc-Si solar-cellapplications can be improved. There has been growing interest in the development of surfacetreatment to enhance light-trapping cells by several methods, such as the use of physicalanti-reflection sputter, reactive ion etcher（RIE）, laser process and acid etching. Among thesemethods, the acid etching for texturing the surface is the major industrial process because ofits low-cost, high etching rate and large-area uniformity. This paper reports the optimizedcondition for crystalline silicon solar cell fabrication, which easily meets the requirement foroptical and electrical performance of solar cells. The main results are as following.（1）The etching rate decreased at first but increased later on with the HNO₃being added. InHF-rich system，low reflectivity surface texture could be obtained, while it was difficult toprint the electrode on the grain boundary when it is deep. In HNO₃-rich system, the surfacereflectivity obtained was higher.（2）There was large difference for reaction rate affecting by temperature as ratio changed inHF-HNO₃-H₂O system. Low-temperature acid etching had more advantages compared toroom-temperature acid etching. Good result was obtained as the HNO₃content decreased atlow-temperature acid etching. The optimum technique for textured structure onmulti-crystalline silicon was as following: HF:HNO₃:H₂O=1:4:2, temperature at3℃andetching rate was2.6μm/min,（3）The acid etching occurred at crystal boundary when activation energy was low. Theetching pit had a large H（depth）/R（width） when the reflectivity reached the minimum. Then H decreased and R increased, the surface morphology tended to be smooth. The reflectancedecreased at first, increased later on. Ultimately it tended to be stabilized.（4）In HNO₃-rich system, stable textured surface and production could be obtained byadjusting the temperature and time to control corrosion weight in a certain range. Worm-liketextures could easily meets the requirement for optical and electrical performance of solarcells, which could achieve the best efficiency. The applied was successfully used in25MWproduction line of multi-crystalline silicon solar cell.更多还原