Reduction of surface reflectivity by using double porous silicon layers

The reduction of optical losses is one of the important factors to obtain high efficiency silicon solar cells. It is known that porous silicon can replace the antireflection coating and texturization of surfaces. In our work, we present investigation of double porous silicon (d-PSi) layer structure. The first macro porous layer was created in p-type mc-Si Baysix material. After n+-p junction formation by POCl3 diffusion, the second porous silicon (PSi) layer in the upper part of n+ emitter was made. We have obtained d-PSi structure with effective reflectance of 5.8%. Microstructure of PSi was determined by SEM and TEM investigations. The total reflectivity of the samples, as a function of the wavelength was measured using Perkin-Elmer Lambda spectrophotometer equipment with an integrating sphere