Au-catalyzed self assembly of GeTe nanowires by MOCVD

The Metalorganic Chemical Vapor Deposition process was adopted for the first time to grow GeTe nanowires (NWs) on SiO2/Si substrates. The growth occurred in the presence of Au as metal catalyst species on the SiO2. Morphological, structural and compositional investigations were carried out on the obtained GeTe NWs. Local structural and chemical analyses were also performed on single nanostructures by High Resolution and Analytical Transmission Electron Microscopy. The NWs exhibited random orientations with respect to the substrate surface plane. The typical diameter of the NWs was in the range of 40–60 nm and their lengths up to 4 μm. The structural measurements showed that both cubic and rhombohedral crystalline phases of GeTe are present in the grown structures. The compositional analyses, either performed on large area or on single nanostructures, yielded Ge0.45Te0.55 composition on average; transmission electron microscopy observations revealed that nanowires with diameter <50 nm are single crystals in the cubic phase, [1 1 0] oriented.