EFFECT OF SUBSTRATES ON THE STRUCTURAL AND MORPHOLOGY OF TiO2 THIN FILMS GROWN BY Nd-YAG LASER ANNEALING

Abstract

Thin films of titanium oxide (TiO2), 350–400 nm thick, were prepared by pulsed laser deposition (PLD) on glass/MgO-poly/Si-poly/Si(111)/Si(100) at a substrate temperature of 450°C. The used source was a Nd:YAG laser (λ = 266 nm, ν = 5 Hz, Φ = 2 J/cm2 and τ = 8 ns pulse duration). The effects of substrates on the crystalline structure and morphology of TiO2 thin films have been investigated. X-ray diffraction reveals that the material deposited is polycrystalline titanium oxide having primitive tetragonal anatase-type structure. The lattice parameters, grain size, microstrain and dislocation densities were calculated and correlated with the substrate material and its orientation. The surface morphologies of the TiO2 thin films deposed on different substrates were evaluated by atomic force microscopy (AFM). The optical gap of TiO2 thin film was determined using the optical transmission spectrum and the optical band obtained is equal to 3.24 eV.