Effect of Alumina-Doping on Structural and Optical Properties of Zno Thin Films by Pulsed Laser Deposition

Abstract

Alumina-doped Zinc Oxide (AZO) thin films on quarts glass substrateshave been deposited by pulsed laser deposition technique using a pulsed Nd-YAG laser with the wavelength of (ë= 532 nm) and duration (7ns).The structural and optical properties of these films were characterized as a function of Al2O3 content (0-5w.t%)in the target at substrate temperatures (400°C) and energy fluence (0.4 J/cm2). The X-ray diffraction patterns of the films showed that the undoped and Al2O3 -doped ZnO films exhibit wurtzite crystal structure and high crystalline quality. The optical properties were characterized bytransmittance, absorption spectroscopy measurements. For all films the average transmission in the wavelength range (330-900) nm was over 90% and the absorption edge shifted toward a shorter wavelength as Al2O3 concentration increased. The optical energy gap of Al2O3 doped ZnO thin films, measured from transmittance spectra could be controlled between (3.32eV and 3.59eV) by adjusting alumina concentration. AFM results show that the samples with increasing concentration of Al2O3, the surface roughness increases