Research On Textured Surface Of Black Silicon Solar Cells

Polysilicon although less silicon content, low production cost, but the surface reflectance is as high as 30%, after acid velvet and deposit si3n4 decreased membrane, the surface reflectance is still as high as 22%, high reflectivity and surface shortwave response difference is the main factor restricting the polysilicon solar cell efficiency. This paper, by using the Plasma immersion ion implantation system in the polycrystalline silicon substrate was prepared with texture on the surface of the "black silicon"-named by macroscopic observation into black silicon wafer surface. Black silicon solar cell can effectively improve the conventional acid system, solar battery high reflectivity and the poor effect of short wave. This article on how to reduce the surface reflectance of the reduced surface recombination velocity at the same time, mainly in the following two aspects:1, using plasma immersion ion system in p-type polycrystalline silicon substrate was prepared by different depth of the structure of the black silicon, and study the effect of depth of structure on the performance of the solar cell. The results showed that:with the structure of depth increase, reflectivity falling while surface composite effect is enhanced. When the texture depth of about 200 nm, the structure effect reaches a certain balance between them, the corresponding black silicon solar cell efficiency is highest, at 15.54%, at this time of the preparation parameters are as follows:black silicon SF6/O2 flow rate ratio of 150/50 (unit for SCCM), negative pulse bias -500V, the reaction time for 5 min, RF power is 900W.In addition, in order to further probing into the cause of the inefficient black silicon solar cells, this paper selected the highest efficiency in the experiments of black with polished silicon wafer, conventional acid system wafers and device performance were compared, found that because the black silicon and polysilicon surface texture structure difference, make it not well with conventional solar cells, preparation process parameters match.2, the use of plasma immersion ion system in p-type polycrystalline black silicon substrate preparation, research on the dry and wet method to damage after processing on the properties of black silicon solar cells. This paper first studied the use of HF/HNO3 solution to damage by wet process principle, and exploring the best wet damage condition is:HF:HNO3:H2O=100:2000-1750, corrosion time for 30s. For dry or wet the black silicon to damage process, found that not only cause damage to the ion bombardment layer has been removed, and the texture structure surface more smooth. Relative to not to damage of components, after dry, wet to damage process device of the open circuit voltage and short circuit current increased, the photoelectric conversion efficiency increased by 0.63% and 0.63% respectively.