Highly ordered porous anodic alumina film is prepared by usinga two-step anodic oxidation method.The film is used asa template to fabricate ordered porous Pt/Ag bilayer metal thin film.The metal thin film is transferred onto n-type single crystal silicon wafer and used asa mask to fabricate silicon nanowire array by the metal-assisted chemical etching process.Atomic force microscopy and scanning electron microscopy observations reveal that both of the porous anodic aluminum oxide film and subsequent grown p...