Applied Research Of Acid Textured Multi-crystalline Silicon Wafer By Surfactants Addition

Multi-crystalline solar cell surface chemical texturing, a low cost method, can greatly improve the photoelectric conversion efficiency of the battery, and be suitable for industrial production. But the traditional acidic texturing system is difficult to control the reaction rate. The resulting textured surface always emerge obscure, uneven and high reflectivity. By scanning electron microscopy (SEM) and UV-Vis-NIR spectrophotometer, the influences of reaction ratio, reaction time, and with or without surfactant addition are studied in HF/HNO3, NaNO2/HF/H2O, HF/HNO3/H2O and KMnO4/HF/H2O four texturing system to explore reflectance variation of surfactant addition.In HF/HNO3/H2O system, the oxidation of textured solution increase with the content of HNO3 increase, the surfactant will be oxidized and resulted in over corrosion on silicon wafer, thereby a higher reflecence is obtained than that of the original silicon. Good results are obtained when the content of HNO3 is reduced. The reflectivity can be reduced 20.47%when the multi-crystalline silicon wafer etching 2 minutes in ice cooled solution of HF/HNO3/H2O=1/1/2 with 0.60 gram surfactant I addition.Studies have shown that texturing appear excessive corrosion in HF/HNO3 system without additives addition. However, good antireflection effect is obtained when adding surfactant into HF/HNO3 system. The reflectivity can be reduced 18.38% when the multi-crystalline silicon wafer etching 1 minutes in ice cooled solution of HF/HNO3=3/1 with 0.60 gram surfactant D addition.The new system is based on KMnO4/HF/H2O and NaNO2/HF/H2O texturing and using surfactant to reduce the reflectance of the textured surface. The results show that the reflectivity can be reduced by surfactant addition in both systems. For KMnO4/HF/H2O system, the reflectivity can be reduced 19.02% when the multi-crystalline silicon wafer etching 3 minutes at ambient temperature solution of KMnO4/HF/H2O=3.60 g/30 mL/210 mL with 0.60 gram surfactant D. For NaNO2/HF/H2O system, the reflectivity can be reduced 19.92% when the multi-crystalline silicon wafer etching 2.75 minutes at ambient temperature solution of NaNO2/HF/H2O=0.90 g/150 mL/90 mL with 0.30 gram surfactant B.