Nanocrystallisation of TiO2 induced by dense electronic excitation

Amorphous thin films of TiO₂ grown by pulsed laser deposition and thermal evaporation method are irradiated by swift heavy ions. Nanocrystallisation is induced by dense electronic excitation in films grown by both the methods. The surface morphology is studied by atomic force microscopy (AFM). Hillocks-like nanostructures emerge on the surface of irradiated films. Glancing angle X-ray diffraction (GAXRD) and Raman spectroscopy are carried out for phase identification. Optical characterisation is done by UV-vis absorption spectroscopy. Increase in bandgap after irradiation indicates quantum confinement of nanoparticles. Mechanism behind amorphous to nanocrystalline phase transition is discussed.