| Along with the development of human society and the world demand for energy is also increasing, but fossil energy which is the absolute subject status in current energy structure dried up. Especially the wide spread use of fossil energy lead to serious environment problems is terrible, so energy and environmental problems has become a barrier of human society continued development and which has attracted worldwide attention. Seeking a renewable, green non-pollution and inexhaustible of new energy is an urgent need to solve the problem.Solar energy is a kind of the new energy which is inexhaustible, clean and non-pollution and is widely distributed, so the prospect of its application is full of attractive. The direct approach of solar energy application is the use of photovoltaic solar cells, so how to improve the photoelectric conversion efficiency of solar cell becomes a research focus all over the world. It is known that texturization technology can reduce the reflection losses and increase the utilization rate of light, and then improve the photoelectric conversion efficiency of solar cell. So the battery surface texture of light absorption is particularly important means to improve the photoelectric conversion efficiency of solar cell. Many kinds of methods are used to prepare the surface texture of silicon wafer. With the development of laser technology and mature, the surface texture of silicon wafer use laser etching which has become a research hot pot. In this thesis, researches of laser technologies applied in the fabrication of crystalline silicon solar cells are carried to improve efficiency. Specific content is as follows:(1) The research of laser processing parameters during laser texturization of multicrystalline silicon wafer. In this work, the mc-Si surface was textured by a 1064 nm wavelength laser. The surface morphology was characterized by scanning electron microscopy(SEM), the surface reflectance of the etched multicrystalline silicon wafers were analyzed by spectrophotometer. We explore how the different output power, etching speed and laser frequency influence laser surface treatment, so as to optimize the preparation of mc-silicon surface texture in the process of laser processing parameters.(2) The research of chemical method to remove the residual layer after laser etching. The defects of laser texturization mainly have damaged layer of the silicon wafer surface and leaving a lot of melted layer. In this paper, we use the Na OH solution to remove the laser induced surface damage layer. The surface morphology was characterized by scanning electron microscopy(SEM), the surface reflectance of the etched multicrystalline silicon wafers were analyzed by spectrophotometer. The concentration of the corrosion solution, the corrosion reaction time and the corrosion reaction temperature of the impact factors of the Na OH solution are researched. We gain the best chemical technology parameters to remove defects after laser texture.(3) The research of incident angle of laser texturization of multicrystalline silicon wafer. Tracepro was applied into the optical simulation of tilt etching structure and vertical etching structure, the results show that texturization structures have the potential to decrease the reflectance. Among that, the tilt structure performs much better than others. In order to examine the angles of incidence of textured optical micro structures, further experiments were conducted. Surface texturization of multicrystalline silicon wafers were prepared by laser etching and the angles of incidence were 0°、30°、45° 、 60°. The surface morphology and reflectivity property of samples were characterized by scanning electron microscopy(SEM) and spectrometer. The results exhibit that with the laser etching angles different, surface reflectivity of polycrystalline silicon changes obviously and when the etching angle is 45°,the surface reflectivity decreased most significantly. |
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