Influence of the indium incorporation on the structural and electrical properties of zinc oxide films

Undoped and indium-doped ZnO films have been deposited onto glass substrates by the spray pyrolysis method. The effect of indium incorporation on structural and electrical properties of ZnO films has been investigated. Zinc acetate dihydrate, indium chloride were used as a starting material and a dopant source, respectively. X-ray diffraction pattern of the films showed hexagonal wurtzite type polycrystalline structure. The results show that indium incorporation leads to substantial changes in the structural characteristics of ZnO films. The grain size was found to be in the range 15-50 nm, depending on indium content. In addition, the surface morphology features of the films, as a function of the indium content, are shown. For all the films, a linear dependence typical of ohmic behavior was observed. The electrical conductivity of ZnO films was improved by indium incorporation. The most important changes were observed for 1 at.% In-doped ZnO film which exhibit a resistivity of 3.2x10(-1) Omega cm. At certain constant voltage, from Arrhenius plots of In-doped ZnO films, activation energy values have been calculated from 17 meV to 89 meV.