Growth, structural, Raman, and photoluminescence properties of rutile TiO2 nanowires synthesized by the simple thermal treatment

We have used the simple heating technique for growing TiO2 nanowires. We have changed the thickness of predeposited Au layers on TiAlN substrates, realizing that the thickness of the Au layer influenced the resultant morphology of nanowires. The nanowires were analyzed with X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and photoluminescence spectroscopy (PL). The resultant nanowires consisted of the tetragonal rutile structure of TiO2. With the nanowire morphology changing with varying the Au layer thickness, we suggest that the associated growth mechanism is a base-growth mode, in which Au played a catalytic role. PL spectra indicated that the TiO2 nanowires exhibited a broad emission band comprising four peaks centered at 3.0, 2.6, 2.3, and 1.5 eV.