The columnar structure of ZnO thin films with respect to the deposition angle prepared by single source chemical vapor deposition (SSCVD) on Si(100) substrate was examined. Growth was performed using a volatile precursor. It was found that the columnar structure depended on the angle between substrates and vapor sources during deposition. However

the XRD spectra indicated that the [002] crystallographic orientations of ZnO thin films were perpendicular to the substrate planes

irrespective of deposition angle and not aligned with columnar growth orientations as may be expected. The

c

-axis orientation of SSCVD ZnO thin films is easily aligned with the surface of substrate because of its surface anisotropy and the optimal growth is on its high-density face (002) with the lowest face free energy.