TITLE:
Effect of Zn Sputtering Rate on the Morphological and Optical Properties of ZnO Films
AUTHORS:
Michel Chaves, Erica Pereira da Silva, Steven Frederick Durrant, Nilson Cristino da Cruz, Paulo Noronha Lisboa-Filho, José Roberto Ribeiro Bortoleto
KEYWORDS:
ZnO Thin Films; Surface Morphology; Optical Properties; OES
JOURNAL NAME:
Materials Sciences and Applications,
Vol.4 No.12,
December
24,
2013
ABSTRACT:
Zinc oxide (ZnO) thin films were deposited onto glass substrates by reactive radiofrequency (RF) magnetron sputtering using a metallic zinc target. Optical emission spectroscopy (OES) was used to monitor and control the Zn sputtering rate for the deposition of the ZnO films. Film thicknesses ranged from 350 to 750 nm. Optical transmittances greater than 80% were observed in the wavelength interval from 450 nm to 650 nm. The energy gap of the films remained constant at (3.28 ± 0.01) eV. The surface morphology was found to be homogeneous with well-distributed structures. Surface roughness was dependent on the Zn sputtering rate, indicating that greater densities of Zn atoms increase the surface diffusion. X-ray diffraction (XRD) analysis showed that the ZnO films were polycrystalline with a hexagonal wurtzite structure and preferential growth along the (002) plane.