Synthesis of silicon nanowalls exhibiting excellent antireflectivity and near super-hydrophobicity

Abstract

Silicon nanowalls have been fabricated on top of p-type silicon (100) wafer using a cost-effective metal assisted chemical etching method. The results obtained from the scanning electron and transmission electron microscopies as well as X-ray diffraction studies have shown that the silicon nanowalls are vertically aligned, single crystalline and exhibit the same crystallographic orientation of the base silicon wafer. It is shown from the spectral reflectance measurements that the silicon nanowalls atop the Si wafer produce very low reflectance signals with a solar-weighted reflectance (Rsw) value of 1.48% over the entire wavelength region of interest for crystalline Si solar cell (220–1107 nm). This observation is in direct contrast with the polished Si wafer that yields a high (Rsw) value of 44%. In addition, the wetting contact angle measurements reveal that the silicon wafer surface structured with silicon nanowalls becomes near super-hydrophobic with excellent water repellent properties.