Structural Properties and Wettability of TiO₂ Nanorods

The structural and wetting properties of as-deposited, annealed, and UV-exposed TiO₂-slanted nanorods grown on different substrates have been studied. The slanted nanorods of 250 nm thickness are deposited on silicon, fluorine-doped tin oxide, and glass at 80° using glancing angle deposition (GLAD) by employing e-beam evaporation. The structural evolution shows that the prior seeding on the substrate affects the morphology dramatically, while a different angle of deposition can tune a plane substrate for exciting morphologies by GLAD technique. Annealing and UV exposure redefine the grown material and change the structural and wetting behavior of the TiO₂ films. Notably, annealing the sample at 500 °C for 1 h has decreased the contact angle, and all the annealed samples become hydrophilic. Further, the UV radiation exposure makes all the samples super-hydrophilic. It is demonstrated that by choosing an appropriate substrate, controlled properties of our interest with or without external stimuli can be achieved. Nevertheless, these samples will find interesting applications in self-cleaning, photocatalysis, gas sensing, antireflection coating, etc.