Characterization and properties of a textured silicon surface with nano-porous layer

The nano-structural anti-reflection layers were investigated. Nano-porous layer was formed on Si substrates by electrochemical etching in HF-based electrolyte. Porous Si layer on the front surface of n+/p monocrystalline, textured Si substrate have been investigated with the aim of improving the performance of silicon solar cells, because an antireflection coating and a surface passivation can be obtained simultaneously in one process. The nanostructure of porous Si is well aligned with the underlying crystalline Si lattice. The formation of a porous Si layer about 100 nm thick on the textured silicon wafer result in an reflectance lower than 5% in the wavelength region from 500 to 900 nm. Such a surface modification allows improving the Si solar cell characteristics.