Bandgap tailoring of rutile TiO2(110) via surface patterning with electron cyclotron resonance sputtering

Crystalline TiO2 nanodots have been formed on single crystal rutile TiO2 (110) surfaces via ion beam sputtering method by utilizing Ar ion beams from electron cyclotron resonance source. Nearly five times enhancement in absorbance of visible light, similar to 5 times increase in luminescence, and similar to 0.1 eV narrowing of bandgap are observed for nanodot-patterned surfaces, in the absence of any dopant material. Formation of crystalline rutile TiO2 nanodots and development of Ti interstitials on the TiO2 (110) surface, after ion beam sputtering, are responsible for these observations. Results suggest that these nanodot-patterned rutile TiO2 surfaces can become effective photocatalysts. (C) 2011 American Institute of Physics. [doi:10.1063/1.3549768]