【作者】 崔方明；

【导师】 杨德仁；

【作者基本信息】 浙江大学 ， 材料物理与化学， 2008， 博士

【摘要】 随着人类经济的发展,能源问题已经成为世界各国面临的首要问题,清洁的可再生能源的研究和开发是国际学术界关注的重点。太阳能是一种取之不尽,用之不竭的无污染洁净能源。从20世纪50年代开始,太阳电池的研究和应用逐渐广泛。CuInS₂（CIS）是一种低温相为黄铜矿结构的化合物半导体,其禁带宽度为1.3～1.7eV,光吸收系数达10⁵cm^-1,较高的吸收系数使得CuInS₂薄膜不需要很大的厚度就可以对太阳光充分吸收,从而使其成为非常有潜力的一种太阳电池吸收层材料。目前制备CuInS₂薄膜材料的工艺路线比较复杂,成本高,严重阻碍着CuInS₂薄膜太阳电池的发展。ZnS是一种Ⅱ-Ⅵ族化合物直接带隙半导体材料,禁带宽度为3.6-3.8ev,对可见光波段的吸收较小,生长过程中需要的温度较低,是一种很好的替代毒性CdS的太阳电池缓冲层材料。目前主要采用化学水浴法制备ZnS薄膜,但是制备工艺不够成熟,重现性不好。本文利用低成本、非真空的化学法,制备了太阳电池用CuInS₂材料和缓冲层ZnS薄膜材料,并研究了其结构和性能,分析了生长机理。其中在酸性条件下采用化学水浴法制备CuInS₂薄膜和采用化学镀法制备CuInS₂薄膜是本文重点研究的技术,酸性条件下沉积CuInS₂薄膜可以抑制杂质的产生,提高薄膜纯度,两种方法均不需要真空条件,因而对设备的要求低,所需成本较低,有利于实现产业化,同时还具有工艺参数易于控制,制备的薄膜均匀且结晶性能好等特点。通过研究,本文取得的主要创新成果如下:1.优化了相关参数,得到了一步法沉积CuInS₂薄膜的稳定工艺,并初步探讨了化学水浴法生长薄膜的机理;研究了衬底和络合剂对薄膜沉积的影响,发现在ITO衬底上沉积和添加络合剂可以使薄膜致密化;研究了热处理对一步法沉积的CuInS₂薄膜结晶及光电性能的影响。2.采用多步化学水浴法制备了CuInS₂薄膜,优化了相关参数。研究了不同衬底对In₂S₃薄膜形貌及与衬底结合力的影响,发现在相对粗糙的衬底上沉积的In₂S₃薄膜与衬底的结合力较好,衬底对In₂S₃薄膜的表面形貌影响不大;研究了表面活性剂对沉积In₂S₃薄膜的影响,发现表面活性剂可以提高In₂S₃薄膜的致密度;研究了热处理对多步法沉积的CuInS₂薄膜结晶及光电性能的影响,发现了与上述一步法热处理相似的规律.3.研究了还原剂对化学镀法沉积Cu膜和In膜的影响,优化了相关参数,得到了沉积Cu膜和In膜的稳定工艺;研究了不同热处理方法对制备CuInS₂薄膜的影响,发现采用单步硫化法得到的CuInS₂薄膜的表面有很多气孔,采用多步硫化法得到的薄膜表面致密。4.采用化学水浴法制备的ZnS薄膜在可见光范围内的透过率在90%以上,薄膜的禁带宽度为3.8eV左右,适合做CuInS₂薄膜太阳电池的缓冲层。更多还原

【Abstract】 With the development of economy, energy has become the principle problem which many countries are faced with in the world. Research and development of the clean renewable energy has become the critical concern of international academic circles. Solar energy is inexhaustible and free from pollution. From 1950s, research and application of solar cell is increasingly wide. Chalcopyrite compound copper indium disulfide （CuInS₂） existed at low temperature is one of the most promising candidates as absorber materials for photovoltaic applications due to its’ direct band gap of 1.3-1.7eV, high absorption coefficient of 10^-5cm^-1 which makes it only need thin thickness to absorb most of the sunlight. At present, preparation process of CuInS₂ thin film is complicated, which costs too much and badly affects the industrialization of CuInS₂ solar cell.ZnS belongs toⅡ-Ⅵwith direct band gap of 3.6-3.8eV, it is almost transparent to visible light and can grow under low temperature. It is a good buffer layer as a substitute of CdS for thin films solar cells. Now ZnS thin film is mainly prepared by Chemical Bath deposition method, but fabrication process is not mature and repeatability is not good.In this thesis, CuInS₂ and ZnS thin films used for solar cell are prepared by chemical method which is low cost and need not vacuum equipment, the structure and property of the films are studied, the growth mechanism of the film is analyzed. Fabrication of CuInS₂ thin film by Chemical Bath deposition in acid conditions and Electroless plating method is mainly studied in this thesis. Fabrication of CuInS₂ thin film by Chemical Bath deposition in acid conditions can restrain the generation of impurities and improve the purity of the film. These two methods both need not vacuum equipment and cost low, which is good to the industrialization of CuInS₂ solar cell. There are some other strongpoints about these two methods, such as process parameters can be easily controlled, the film is uniform and well crystallized. The main creative achievements are showed as follows: 1. Related parameters are optimized and stable process for preparation of CuInS₂ thin film by Chemical Bath deposition is obtained, growth mechanism of thin film prepared by Chemical Bath Deposition is also analyzed; the effect of substrate and complexing agent on the deposition of the film is studied, it is found that deposition on the ITO substrate and with complexing agent can make the film compact; effect of the heat treatment on the crystallization and optoelectrical property of the film is also investigated.2.CuInS₂ thin film is prepared by multi-step Chemical Bath deposition, related parameters are optimized. Effect of substrate on the In₂S₃ film surface morphology and adhesion between In₂S₃ film and the substrate is studied, it is discovered that rough substrate can make the adhesion better, but different substrates have little effect on the In₂S₃ film surface morphology; effect of surface active agent on the deposition of In₂S₃ thin film is investigated, it is found that surface active agent can make the film compact; effect of the heat treatment on the crystallization and optoelectrical property of the film is studied, it is showed that the the anneal effect on the film by multi-step Chemical Bath deposition has similar discipline with the one-step method.3. Effect of reducing agents on the preparation of Cu and In film by Electroless Plating method is studied, related parameters are optimized and stable process for preparation of Cu and In thin film by Electroless Plating method is obtained; effect of different anneal methods on the preparation of CuInS₂ film by Electroless Plating method are studied, it is found that there are many holes on the surface of the CuInS₂ film annealed by one-step sulfuration, but the film annealed by two-step sulfuration is compact.4. The transmisson of the ZnS film prepared by chemical bath deposition is more than 90% at the range of visible light, the film with band gap of 3.8eV is very suitable to be used as the buffer layer of CuInS₂ thin film solar cell.更多还原