Pulsed laser deposition growth of rutile TiO2 nanowires on Silicon substrates

TiO2 nanowires (NWs) were grown on a (1 0 0)-oriented silicon substrate by pulsed laser deposition. Our growth strategy involves consecutive deposition of a Au/Ti bilayer followed by annealing to promote TiO2 NW growth. Deposition at various laser energy densities suggests that vapor-liquid-solid growth of TiO2 is sensitive to Ti flux. Raman spectroscopy of NWs grown under optimized PLD-conditions reveals the rutile phase of TiO2 NWs. Optical measurements on the TiO2 NW arrays under light excitation at 355 nm wavelength show a strong and sharp photoluminescence peak at 3.41 eV, which we attribute to a direct recombination of photoinduced charge carriers.