Effect of substrate temperature on microstructure and properties of nanocrystalline titania thin films prepared by pulsed laser deposition

Titanium oxide (TiO$_2$) films were deposited on silicon (100) and quartz substrates at various substrate temperatures (300 – 873 K) at an optimized oxygen partial pressure of 3.0$\times$10$^{-2}$ mbar by pulsed laser deposition. The effect of substrate temperature on structure, surface morphology and optical properties of the films were investigated using X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence spectroscopy (PL) respectively. The XRD results showed that the films are polycrystalline in nature and have tetragonal structure. The film prepared at higher substrate temperature showed strong rutile phase. The results indicated that all the films possess both phases (anatase and rutile) of titania. The AFM shows the crystalline nature, dense, uniform distribution of the nanocrystallites with a surface roughness of 2 – 8 nm. The photoluminescence studies showed the asymmetric peak $\sim$370 nm indicating the bandgap for the TiO$_2$.