Triangular network of crystalline submicron rutile TiO2 block assembly: An alcohol sensor

RF sputtering technique was used to obtain periodic submicron triangular TiO2 blocks on quartz substrates at 500 °C. Preferentially oriented XRD patterns exhibiting the strongest line at 2θ = 27.78° suggested a rutile TiO2 block assembly. X-ray photoelectron spectroscopy confirmed that the surface composition of the particles corresponded to TiO2 with the absence of Ti3+ species at 500 °C after sputtering. Analysis of AFM images indicated that the single crystals were triangular in shape, self-assembled across the quartz surface. The sides of the triangular crystal obtained at 500 °C were found in the submicron range of 100–225 nm, whereas those sputtered at 300 °C were in the range of 250–375 nm. The image Z-range, Rq, Ra of TiO2 single crystal deposits sputtered at 500 °C were found to be 19.6, 3.1 and 2.5 nm, respectively, evidencing a smooth surface and regularly assembled single crystals. The crystalline submicron TiO2 film exhibited a sensor signal in the range of 2.3–10.8 to a low concentration (10–50 ppm) of alcohol at 250–500 °C. The reversibility of the sensor was also assessed.