A simple solvothermal route to controlled diameter germanium nanowires

A simple solvothermal method has been developed to synthesize germanium nanowires with excellent single crystalline diamond cubic structure that exploits the use of preformed Au nanoparticle seeds on high surface area alumina powders. The nanowires exhibit a narrow diameter distribution, with typical diameters of 40 ± 7 nm and 80 ± 5 nm, using 40 nm and 80 nm Au seeds, respectively. The preferred growth direction of the Ge nanowires is along the [111] direction. The use of high surface area alumina powder, modified by 3-aminopropyltriethoxysilane (APTES), provides an effective way to capture individual nanoparticle seeds, which prevents aggregation and provides monodispersed seeds for nanowire growth. This approach is a viable alternative to higher temperature vapor-phase methods, yielding materials of comparable quality and improved size control and thus represents a low cost route to controlled germanium nanowires.