Preparation of Porous Silicon Templates in Two Steps of Au-Assisted Chemical Etching

Porous silicon templates have been prepared by the metal-assisted chemical etching approach with gold (Au) nanoparticles as the catalyst. The Au nanoparticles of 30 nm in mean diameter and a distance of 100 nm between each other were arranged on the surface of Si substrate through the polystyrene (510000)-block-poly(2-vinylpyridine) (31000) (PS510000-b-P2VP(31000)) diblock copolymer. The effects of concentration of HF and etching temperature on the morphologies of the obtained nanopores have been investigated. It was found that the morphology of porous silicon can be tailored by adjusting the concentration of HF and etching temperature. Subsequently, porous silicon templates possessing pores with 500 nm in mean diameter and a 500 nm distance between the pores have been successfully fabricated in two etching steps. The porous silicon templates are believed to be potentially employed for fabrication nanowires (nanotubes) devices compatible with semiconducting industries.