Reseach On Wet Etching Combined With ZnO Nanorods As Si Solar Cell Antireflection Layer

Solar cell can change light into electricity efficiently to be used by human. Thus, improving the conversion efficiency is widely investigated all over the world and has great meaning. There is a critical technology to improve the conversion efficiency, which is to let solar cell surface absorb more light. An antireflection layer can decrease reflection of light within a wide range of wavelength and increase absorption of the light by solar cell.In this paper, we used gradually increased reflectivity antireflection layer to reduce reflection of silicon surface. The hydrothermal method is used to grow zinc oxide nanorods on the surface of the silicon to reduce reflection and increase absorption of light. First we used FDTD simulation to find suitable morphology of the ZnO nanorods, and then we changed the conditions of the hydrothermal method to synthesize different morphologies of nanorods and to achieve lowest reflectivity. We successfully decreased the reflectivity of the polishing silicon surface from35%into less than10%.We also anisotropically wet etched<100> silicon by Tetramethyl Ammonium Hydroxide (TMAH) solution to fabricate pyramidal like structures and the reflectivity of the Si surface is reduced to around7%. Then ZnO nanorods were grown on the etched surface by hydrothermal method. By this method, the minimum reflectivity of the surface is lower than3%, better than that from the TMAH etched surface or ZnO nanorods covered surface only. This method is simple, effective, costless, and has great potential.We synthesized ZnO nanorods on the surface of solar cell. By standard test, we find that the conversion efficiency has increased from the original10.8%to14.1%, almost30%higher than the original one. Other parameters such as short circuit current, open circuit voltage, and fill factor have also increased.