Optical and electrical properties of ZnO films deposited by activated reactive evaporation

ZnO films having good transmittance and conductivity were deposited by activated reactive evaporation of Zn metal on glass and Si substrates at room temperature. Optical constants and thickness of ZnO films deposited under different deposition conditions were determined both by spectroscopic ellipsometry (SE) and spectrophotometry. Structural studies showed that the films exhibited a polycrystalline wurtzite structure with the preferential oriented along the (002) plane. Electrical studies by four probe technique showed that the sheet resistance of the films varied from 106 to 50 Ω/square depending upon the oxygen partial pressure used during deposition, and this sheet resistance value increased with time. The increase in sheet resistance with time was found to be dependent on the surface morphology of the film and on the substrate over which they were deposited.