Optical characterization of filtered vacuum arc deposited zinc oxide thin films

Cetinorgu E., Goldsmith S., Zhitomirsky V. N. , Boxman R. L. , Bungay C. L.

SEMICONDUCTOR SCIENCE AND TECHNOLOGY, vol.21, no.9, pp.1303-1310, 2006 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 21 Issue: 9
  • Publication Date: 2006
  • Doi Number: 10.1088/0268-1242/21/9/015
  • Page Numbers: pp.1303-1310


ZnO thin films, 100 - 250 nm thick, were deposited on microscope glass slides and UV fused silica (UVFS) substrates using a filtered vacuum arc deposition (FVAD) system, operating at room temperature (RT) and 200 A for 60s. The cathode was prepared from 99.9% pure Zn metal and the oxygen background pressure during deposition was in the range 0.67 - 0.93 Pa. The films were characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), optical transmission and spectroscopic ellipsometry. As-deposited ZnO films were found to be polycrystalline with c-axis orientation. The atomic concentration ratio of Zn to O in the film as determined by XPS analysis was stoichiometric. Film transmission in the visible was 70 - 90%. The maximum and minimum values of the refractive index n and the extinction coefficient k in the visible, for all samples, were 2.23 to 1.90 and 0.6 to approximately 0, respectively. The type of inter-band electron transition was found to be direct transition with optical band gap in the range of 3.25 - 3.42 eV.