基于飞秒激光刻蚀的黑硅太阳电池的制备及其性能优化

发布时间：2018-04-18 13:09

  本文选题：飞秒激光 + 黑硅　； 参考：《上海理工大学》2014年硕士论文

【摘要】：太阳能是一种取之不尽、用之不竭的绿色能源,使用太阳电池进行发电是利用太阳能的最有效途径。然而,传统硅基太阳电池的光电转换效率仅为18%左右,其效率低的主要原因是硅材料为间接带隙半导体,载流子跃迁至导带需要的光子动能远高于砷化镓等直接带隙半导体,形成很大的能量浪费。但是,硅材料的价格优势使硅基太阳电池依旧占据市场总量的90%以上,所以,进一步提升硅基太阳电池转换效率对推动光伏产业的发展具有极其重要的研究意义。制约硅基太阳电池效率提高的阻碍主要有两条:1,未经特殊处理的硅表面具有较高的反射率,被反射的阳光无法转换为电能,形成能量损失;2,硅材料禁带宽度较窄,无法吸收并转换红外光子。本论文主要针对问题1进行了研究工作。1998年,具有特殊陷光性能的“黑硅”材料被发现,其对可见光与红外光的吸收率均超过90%,正好弥补了传统硅材料在陷光方面的不足,在太阳电池领域被认为极具发展前景。然而黑硅材料表面包覆着缺陷态密度极高的激光刻蚀损伤层,极大影响了黑硅太阳电池的转换效率。为了进一步提高黑硅太阳电池的转换效率,本论文主要在两方面进行了研究工作:其一,对去除黑硅材料表面激光刻蚀损伤的方法进行了系统研究;其二,设计了一套适合黑硅太阳电池的制备参数。在对去除黑硅材料激光刻蚀损伤的研究中,本文分析了三种不同的表面损伤去除方法(分别为:表面耦合等离子体刻蚀、各向同性腐蚀法、各向异性腐蚀法)对黑硅太阳电池效率的影响,结果表明,各向异性腐蚀法具有最优的去损伤效果;之后,本文对各向异性腐蚀法的腐蚀时间结合少子寿命测试进行了细致优化,得到了一种奇特的正逆金字塔混合陷光结构。该结构相对传统碱制绒表面具有更低的反射率,同时激光刻蚀损伤也得到了最大程度的去除;为了找到合适的黑硅电池制备参数,本文对与黑硅电池制备相关的工艺参数逐一进行了优化,包括:激光刻蚀功率的优化、表面钝化层的选择以及加入铝背场技术;最后,本文利用优化后的工艺参数进行了黑硅电池的实际制备,并对制得电池的陷光特性、亮场I-V特性、量子效率特性进行了测试与分析。结果表明:在经过表面去损伤处理后,黑硅太阳电池的开路电压与短波内量子效率得到了很大提升;正逆金字塔陷光结构的引入使得黑硅太阳电池的短路电流密度明显高于传统碱制绒电池;最终,本文制备黑硅太阳电池的转换效率从之前最优的14.2%提升至15.6%,同时,本文制备黑硅太阳电池的转换效率也高于同时制备的碱制绒参考电池(转换效率为15.3%)。
[Abstract]:Solar energy is an inexhaustible green energy, the use of solar cells to generate electricity is the most effective way to use solar energy.However, the photoelectric conversion efficiency of traditional silicon based solar cells is only about 18%. The main reason for the low efficiency is that the silicon material is an indirect bandgap semiconductor, and the photon kinetic energy required for carrier transition to the conduction band is much higher than that for direct band gap semiconductor such as gallium arsenide.Form a great waste of energy.However, because of the price advantage of silicon materials, silicon based solar cells still account for more than 90% of the total market. Therefore, it is of great significance to further improve the conversion efficiency of silicon based solar cells to promote the development of photovoltaic industry.The main obstacles to improving the efficiency of silicon based solar cells are two: 1. The surface of silicon without special treatment has high reflectivity, the reflected sunlight can not be converted into electric energy, the energy loss is 2%, and the band gap of silicon material is relatively narrow.Unable to absorb and convert infrared photons.In 1998, the black silicon with special trapping properties was found, and the absorption rates of both visible and infrared light were over 90, which made up for the deficiency of traditional silicon materials in trapping light.In the field of solar cells is considered to have great prospects for development.However, the black silicon material is coated with a highly dense defect laser etching layer, which greatly affects the conversion efficiency of the black silicon solar cells.In order to further improve the conversion efficiency of black silicon solar cells, this paper mainly researches in two aspects: first, the method of removing laser etching damage on the surface of black silicon is studied systematically; second,A set of fabrication parameters suitable for black silicon solar cells was designed.In the study of laser etching damage removal of black silicon materials, three different surface damage removal methods (surface coupled plasma etching, isotropic etching) are analyzed in this paper.The effect of anisotropic etching on the efficiency of black silicon solar cells is studied. The results show that the anisotropic etching method has the best effect of removing damage.In this paper, the corrosion time of anisotropic etching method combined with minority carrier lifetime testing is carefully optimized, and a peculiar mixed trapping light structure with forward and inverse pyramids is obtained.The structure has lower reflectivity than the traditional alkali made surface, and the laser etching damage is removed to the greatest extent. In order to find the appropriate preparation parameters of black silicon battery,In this paper, the process parameters related to the preparation of black silicon battery are optimized one by one, including the optimization of laser etching power, the selection of surface passivation layer and the addition of aluminum backfield technology.In this paper, the practical preparation of black silicon battery is carried out by using the optimized process parameters, and the trapping light characteristics, bright field I-V characteristics and quantum efficiency characteristics of the prepared battery are tested and analyzed.The results show that the open-circuit voltage and short-wave quantum efficiency of the black silicon solar cell are greatly improved after the surface damage treatment.The short circuit current density of the black silicon solar cell is significantly higher than that of the traditional alkaline chorion cell due to the introduction of the positive and inverse pyramid trapping light structure. Finally, the conversion efficiency of the black silicon solar cell prepared in this paper has been raised from the previous optimum of 14.2% to 15.6g, at the same time,In this paper, the conversion efficiency of black silicon solar cells is also higher than that of alkali reference cells.
【学位授予单位】：上海理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM914.41
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本文编号：1768506