SiOx core-shell nanowires generated by heating the multilayered substrates

By heating Au/TiN/Si substrates, we fabricated TiO2/SiOx core-shell nanowires. By changing the thickness of predeposited Au layers, we demonstrated that the thickness of the Au layer needs to be optimized to obtain nanowires. High-resolution transmission electron microscopy image, X-ray diffraction spectrum, and selected area electron diffraction pattern coincidentally revealed that the resultant core nanowires had a tetragonal rutile structure of TiO2, and the shell was comprised of amorphous SiOx. The dominant growth mechanism was a base-growth mode, in which Au played a catalytic role, resulting in morphological changes with variation of the Au layer thickness. The TiO2/SiOx core-shell nanowires exhibited a broad photoluminescence emission band, which comprised four peaks centered at 1.54, 2.34, 2.67, and 2.99 eV, respectively. We expected that the 1.54 eV- and 2.34 eV-centered peaks arised from the TiO2 core, whereas the 2.67 eV- and 2.34 eV-peaks were ascribed to both the TiO2 core and the SiOx shell.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0009946)