Morphological and optical properties of silicon nanoholes produced by Pt-nanoparticles assisted chemical etching

Silicon nanoholes have been fabricated in heavily doped P-type single-crystalline silicon via Pt-nanoparticles assisted chemical etching. The morphologies of silicon nanoholes are modulated by varying etching time and HF concentration, respectively. Vertical aligned cylindrical nanoholes are observed in all fabricated films. As the etching time increase, the diameter of silicon nanoholes stays the same and the depth and roughness increase, though. The reflection spectrum indicates that these silicon nanoholes have great antireflection property and reflectivity as low as 2.5 % is obtained. When the HF concentration is raised, the depth of silicon nanoholes has a maximum and the diameter and roughness decrease. The reflection spectrum shows apparent interference fringes when the HF concentration is very high.