Radio frequency magnetron sputtering growth of Ni-doped ZnO thin films with nanocolumnar structures

This study describes the RF magnetron sputtering growth of nickel (Ni) doped zinc oxide (ZnO) thin films with nanocolumns (NCs) structures. Using a nickel seed layer, homogeneous and vertically aligned ZnO nanocolumns with a diameter of around 30 nm were successfully grown. The X-ray diffraction (XRD) results confirmed the incorporation of Ni atoms into the ZnO lattice, producing single crystalline structures without secondary phases. High-resolution transmission electron microscopy showed clear lattice planes with a d-spacing value of 3.243 & Aring; corresponding to the wurtzite phase of ZnO. Optimal crystalline quality was achieved by growing the films at 300 degrees C followed by thermal annealing at 300-500 degrees C in an oxygen ambient.