Properties of Aluminum-Doped ZnO Thin Films Grown by Electron Beam Evaporation

Abstract

Highly conductive thin films of ZnO have been prepared by conventional electron beam evaporation on glass substrates. The Al₂O₃ content of 0–5 wt% was added as dopant into ZnO to decrease resistivity of ZnO films. An Al-doped ZnO film with a resistivity of 1.0 × 10^-3 Ωcm is obtained at a substrate temperature of 300°C with 1.0 wt% Al₂O₃ content; transmittance of this film is above 90% in the visible range with 100 nm thickness. The ZnO source material doped with Al₂O₃ is evaporated efficiently by a lower electron beam power compared to the case of nondoped ZnO. The c-axis orientation of ZnO films is facilitated by the addition of Al₂O₃ and the c-axis of Al-doped ZnO films is oriented perpendicular to glass substrates in the substrate temperature range of 60°C–350°C.