LAUSR

The third-order nonlinear optical properties of nitrogen-enriched TiO2 films deposited by atomic layer deposition (ALD) at a temperature between 100–300 °C on quartz substrates were studied using thermally managed Z-scan technique. TiO2 oxide films prepared by physical vapor deposition (PVD) at room temperature were used as control samples. The as-grown ALD films deposited at 150–300 °C exhibited values for the nonlinear index of refraction, n2, between 0.6 × 10–11 and 1 × 10–9 cm2/W, which is 4–6 orders larger than previously reported. Annealing the films for 3 h at 450 °C in air reduced the nonlinearities below the detection limit of the experimental setup. Similarly, as-grown 100 °C ALD and PVD films did not produce a discernible Z-scan trace. Composition analysis performed by X-ray photoelectrons spectroscopy (XPS) reveals the presence of Ti—O—N metallic bonds in the films that showed high nonlinear optical response. The presence of the metallic bonding gives the films deposited on Si(100) a golden co...