Co-doped ZnO powder and thin films on Si(1 0 0) substrate were prepared by solid-phase reaction and reactive e-beam evaporation. All samples were characterized by X-ray diffraction. The structure of powder sample was determined using Rietveld full-profile analysis method. The study of the influence of substrate temperature on the structure of thin films samples showed that the quality of thin films depended largely on the substrate temperature. The film prepared at 400 degreesC had the highest quality with c-axis (0 0 2) preferred orientation. (C) 2003 Elsevier Ltd. All rights reserved.