Influence of deposition regime on physical properties of gallium doped zinc oxide films

Zinc oxide films doped by gallium were deposited using RF diode sputtering from a ceramic ZnO + 2% Ga2O3 target on Corning glass in argon atmosphere. Samples were supported in three different positions against a substrate holder horizontal, and at 60 and 80 degrees to the horizontal position. Two series of samples 700-1000 nm in thickness were prepared: one at room temperature (RI) and the second at 200 degrees C. XRD, optical and electrical experiments indicated that the films are polycrystalline having average crystallite sizes from 30 to 80 nm, integrated transmittances in the range of 400-1000 nm increased from 85 to 90 per cent and optical band-gap values increased from 3 to 3.2 eV with higher deposition temperature. The resistivity of the obliquely sputtered samples positioned at 80 degrees to the substrate holder was one order lower than the horizontally positioned samples. No significant changes were observed in case of optical properties of the films in dependence on the tilt-angle. (C) 2011 Elsevier Ltd. All rights reserved.