Fabrication of silicon wafer with ultra low reflectance by chemical etching method

► A pyramid and nanowire binary structure of monocrystalline silicon wafer was fabricated by chemical etching. ► Much lower reflectance of silicon wafer with this structure was obtained compared with that of single pyramid or nanowaire arrays. ► An average reflectance of 0.9% was obtained under optimized condition. ► The formation mechanism of silicon nanowires was explained by experimental evidence.