Insulating Regions in a TiO2 Thin Film Defined by Laser Irradiation

Titanium dioxide (TiO2) has a range of applications including catalysis, hydrogen production, and water purification. In this work, anatase TiO2 was annealed in vacuum at 800 °C, resulting in a conductive thin film. Exposure to subgap laser light (532 nm wavelength) caused a seven order-of-magnitude increase in resistance. Laser-irradiated regions showed an increase in optical transmission, consistent with a reduction in oxygen vacancy concentration. Scanning electron microscopy and Raman spectroscopy indicate that laser irradiation did not change the morphology, composition, or phase of the material.