Laser annealing effect on optical and electrical properties of Al doped ZnO films

Aluminum doped ZnO (AZO) thin films were prepared by RF magnetron sputtering on quartz substrates at room temperature, and then annealed by a Nd:YAG solid-state laser with wavelength 1064 nm under different power densities in the air. The characteristics of films were systematically analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis spectroscopy, spectroellipsometry and Hall measurement at room temperature. The XRD patterns showed that all the films were well crystallized along with c-axial (002). The SEM analysis illustrated obvious grain boundary and non-damage on the surface of films. The grain boundary would result in a decreasing resistivity and a decreasing optical band-gap of the AZO films, which were demonstrated by Hall measurement and UV–vis spectroscopy. The refractive index, the extinction coefficient, and the real and imaginary components of dielectric constant are calculated by spectroellipsometry. The resistivity and transmittance significantly improved when the samples were annealed at 27.8 W/mm2.

► High c-axis Al doped ZnO films were deposited on quartz at room temperature.
► Al doped ZnO films were annealed by a 1064 nm laser at room temperature.
► Different power densities laser were used.
► Improved electrical and optical properties were obviously observed.