Optical properties and surface morphology of pulsed-laser-deposited polycrystalline PNZT thin films

Pulsed XeCl-excimer laser and Nd-modified lead-zirconate-titanate (PNZT) ta rgets were used for the laser-ablation deposition of PNZT thin films on MgO (100) substrates. Films were post-annealed at 700, 800 and 900 degreesC and optical transmission and reflection spectra were measured. AFM and XRD tec hniques were used for structural and surface quality characterization. In t he films annealed at 700 degreesC, the crystal structure was found to be po lycrystalline and the surface quality and optical properties were found to depend also on the laser-beam fluence. However, in the films annealed at 80 0 and 900 degreesC, a growth of large grains, where the < 001 > crystal dir ection was perpendicular to the film surface, was found. The surface morpho logy and optical properties of the films were clearly improved. The band-ga p energy E-g approximate to 3.5 eV, refractive index n approximate to 2.1 a nd extinction coefficient k approximate to 0.014 at the wavelength of 600 n m were calculated. (C) 2001 Elsevier Science Ltd. All rights reserved.