Research On A New Texturization Method For Single Crystalline Silicon Solar Cells

Surface texturization for single crystalline silicon solar cells is an important step in the fabrication process of solar cells. By chemical etching technique pyramidal microstructures on the surface of solar cells can be achieved. The pyramidal structure can reduce the surface reflectance and increase the density of photo-generated carriers. Thereby we can reach the goal of increasing the solar cell's conversion efficiency and reducing the production cost. In this paper we first investigate a new texturing technique with sodium hypochlorite solution. By the auto-oxidation action of the new solution, we can get a layer of silica on the silicon surface which can reduce the size of pyramids (about 1-2μm). With a UV-4100 spectrometer measurement, the surface reflectance of silicon textured with the new technique is lower than that of other techniques. The chemical reaction products with this new method are environment friendly. Also with this method, two step processes can be canceled in the texturing due to the specificity of chemical reagents. Therefore, this new texturization technique is promising to reduce the production cost and improve the solar cells'efficiency.In the first section, we summarize the importance of developing solar energy resources and the current research status. Moreover, we sum up several high performance solar cells in current. Finally we illustrate the significance, innovation and major tasks of this research.In the second part, texturization techniques for monocrystalline silicon solar cells and multicrystalline silicon solar cells are explained, respectively.Finally, we investigate the new texturing technique in detail, including the fabrication of this new method, the comparison of this new technique and the conventional technique. Some potential advantages of this new technique are also concluded. Moreover, we discuss the chemical reaction principles, the formation mechanism of pyramidal nuclei and the influence of several experimental parameters, such as the concentration of solutions, texturing time and reaction temperature, the quality of silicon wafers. At last, we propose the existing problem and its corresponding solutions.