Indium-doped ZnO thin films deposited by the sol-gel technique

Conducting and transparent indium-doped ZnO thin films were deposited on sodocalcic glass substrates by the sol-gel technique. Zinc acetate and indium chloride were used as precursor materials. The electrical resistivity, structure, morphology and optical transmittance of the films were analyzed as a function of the film thickness and the post-deposition annealing treatments in vacuum, oxygen or argon. The obtained films exhibited a (002) preferential growth in all the cases. Surface morphology studies showed that an increase in the films' thickness causes an increase in the grain size. Films with 0.18 mu m thickness, prepared under optimal deposition conditions followed by an annealing treatment in vacuum showed electrical resistivity of 1.3 x 10(-2) Omega cm and optical transmittance higher than 85%. These results make ZnO:In thin films an attractive material for transparent electrodes in thin film solar cells. (c) 2005 Elsevier B.V. All rights reserved.