We report a direct growth of highly conductive nanocrystalline graphene on dielectric SiO2 nanowires. Graphene structure on the nanowire surface is easily controlled by adjusting the growth conditions. In addition, highly dense ZnO nanorods are electrochemically grown on graphene/dielectric nanowire, which demonstrates potential for the nanostructured electrode with controlled morphology.

Carbon-containing alloy materials such as Ge(1-x)C(x) are attractive candidates for replacing silicon (Si) in the semiconductor industry. The addition of carbon to diamond lattice not only allows control over the lattice dimensions, but also enhances the electrical properties by enabling variations in strain and compositions. However, extremely low carbon solubility in bulk germanium (Ge) and thermodynamically unfavorable Ge-C bond have hampered the production of crystalline Ge(1-x)C(x) alloy materials in an equilibrium growth system. Here we successfully synthesized high-quality Ge(1-x)C(x) alloy nanowires (NWs) by a nonequilibrium vapor-liquid-solid (VLS) method. The carbon incorporation was controlled by NW growth conditions and the position of carbon atoms in the Ge matrix (at substitutional or interstitial sites) was determined by the carbon concentration. Furthermore, the shrinking of lattice spacing caused by substitutional carbon offered the promising possibility of band gap engineering for photovoltaic and optoelectronic applications.

The crystalline germanium nanowires (GeNWs) with a uniform graphitic carbon shell were prepared via a conventional low-pressure chemical vapor deposition method without any external catalyst. The GeNWs grown at low temperature (Tg < 500 degrees C) have a uniform diameter with a large expect ratio of more than 10(3). With increasing the growth temperature (Tg > 500 degrees C), however, the nanowire morphology is dramatically changed into a hybrid structure where highly dense Ge nanoparticles (GeNPs) with a diameter of 5-10 nm are attached onto the Ge nanowires. The nanostructures consist of crystalline Ge-core and very thin graphitic carbon shell. The possible mechanism of anisotropic growth and the control of morphological transition from uniform nanowires to NW/NP hybrid structures are discussed and demonstrated.