Characterization of Transparent Conducting Pulsed Laser Deposited Films in the Indium Zinc Oxide System

Thin films of indium zinc oxide so called IZO were prepared with pulsed laser deposition. It was found that the crystalline structure, the composition and the morphology of the films as well as the optical and electrical properties were quite sensitive to the deposition conditions namely to the temperature and oxygen pressure. The crystallinity of the ZnkIn2O3+k (k from 1 to 5) thin films increases as the substrate temperature increases. An average transmittance of 85 % in the visible region was obtained for any k values. Optical measurements show a continuous decrease of the band gap as the zinc amount increases. The highest conductivity reported is for the ZnIn2O4, thin films deposited at 300 °C (σ = 1.2 103 S/cm). Increasing the amount of Zn (i.e. k value) was found to result in a conductivity decrease. Finally, a good correlation between the electric mobility and the optical mobility is obtained.