Size-controlled template synthesis of metal-free germanium nanowires

Porous anodic aluminum oxide (AAO) membranes are well-established templates used for the fabrication of one-dimensional nanostructures. Herein, we report a straightforward synthesis of one-dimensional germanium nanostructures via templated reductive thermal processing of a GeO2-like sol-gel derived precursor. This method affords polycrystalline Ge nanowires (Ge-NWs) without employing any catalyst or seed. Furthermore, the Ge-NW dimensions may be tuned by changing the pore sizes of the templates and the heat processing time. The Ge-NWs are readily liberated from AAO templates by dissolution in 15% H3PO4 solution.