Simulation Of Dual Antireflectiion Coating And Its Application To The Solar Cells

Solar cell is the semiconductor device which can convert the photon energy into electricity power. It is crucial for us to study the optical and electrical properties of solar cells, which could help us utilize the solar energy sufficiently, improve the conversion efficiency and diminish the cost of solar cells. In this study, we mainly investigate the effect of surface passivation and antireflection coating design on solar cells, and manufacture the solar cells with TiO₂/SiO₂ dual antireflection coating based on the simulation.Thermal grown SiO₂ thin film has an excellent electronic passivation on silicon surface. In order to improve the passivation quality, the technological parameters were optimized by changing the growing temperature, time and gas-flow rate of O₂, it was demonstrated that the SiO₂ film grown under the condition of 850℃and the thickness of 10nm, is the best for silicon wafer passivation in this work, and there is little effect both on the p-n junction depth and carriers concentration on silicon surface under that optimized condition.To further decrease the reflectivity on the wafer surface, DLAR（dual layer antireflection） coating on solar cells is designed. First, we select TiO₂ as the upper layer, and SiO₂ as the bottom layer. The thickness of SiO₂ is 10nm, and the refractive index is 1.46, and then calculate the reflectivity when the thickness of upper layer is changed from 40 to 80nm by optical simulation software Macleod, finally make a program of evaluation function. The results indicate that DLAR reflectivity is the lowest when the thickness of TiO₂ is 10nm.After preparing the dual antireflection on the solar cells production line, we find that this TiO₂/SiO₂ DLAR coating has as good passivation and anti-reflectivity effect on silicon surface as SiNx antireflection coating. Both open-circuit voltage of the solar cells with different ARC are 0.62V; The conversion efficiency of TiO₂/SiO₂ DLAR coating and SiNx single coating solar cells are16.02% and 16.2% respectively; Finally, it is indicated that the internal quantum efficiency of solar cells with TiO₂/SiO₂ improved a lot, compared with solar cells with SiNx film. So this low cost DLAR coating is expected to be used widely in PV industry.