Air annealing effects on the optical properties of ZnO-SnO2 thin films deposited by a filtered vacuum arc deposition system


Cetinorgu E., Goldsmith S., Boxman R.

SEMICONDUCTOR SCIENCE AND TECHNOLOGY, cilt.21, ss.364-369, 2006 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 21 Konu: 3
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1088/0268-1242/21/3/027
  • Dergi Adı: SEMICONDUCTOR SCIENCE AND TECHNOLOGY
  • Sayfa Sayısı: ss.364-369

Özet

ZnO-SnO2 transparent and conducting thin films were deposited on microscope glass substrates by a filtered vacuum arc deposition (FVAD) system. The cathode was prepared with 50%:50% atomic concentration of Zn:Sn. The filins were annealed in air at 500 degrees C for 1 h. Structural and compositional analyses were obtained using XRD and XPS diagnostics. X-ray diffraction analysis indicated that as-deposited and air-annealed thin ZnO-SnO2, films were amorphous. The atomic ratio of Zn to Sri in the film obtained using the 50%:50% cathode as determined by XPS analysis was similar to 2.7:1 in the bulk film. The optical properties were determined from normal incidence transmission measurements. Film transmission in the visible was 70% to 90%, affected by interference effects. Annealed films did not show higher transmission in the VIS compared to as-deposited films. Assuming that the interband electron transition is direct, the optical band gap was found to be in the range 3.34-3.61 eV for both as-deposited and annealed films. However, the average E-g for annealed films was 3.6 eV, larger by 0.2 eV than that of as-deposited. The refractive index n increased while the extinction index k decreased significantly with annealing.