Effects of Mg substitution on the structural, optical, and electrical properties of CuAlO2 thin films

Mg-doped CuAlO2 thin films are prepared by the chemical solution method. The XRD results show that the solid solubility of Mg species on Al sites in CuAlO2 lattice is lower than 2 at.%. When less than 2 at.% of Mg is added to the CuAlO2 film, the surface roughness of the films was reduced with Mg substitution. Moreover, the c-axis orientation of the films improves because the in-plane fusion between CuAlO2 crystallites is hindered. Optical and electrical measurements show that substituting Al3+ in the films with Mg2+ increases both their transmittance in the visible region and their optical band gaps. As well, their electrical conductivity is enhanced. At 300 K, the conductivity of the 1 at.% Mg-doped sample is up to 5.2 x 10(-3) S/cm. Thus, Mg-doped CuAlO2 films may have potential applications as transparent conductive oxides. Published by Elsevier B.V.