Local homoepitaxy of zinc oxide thin films by magnetron sputtering

High quality zinc oxide (ZnO) thin films have been deposited on c-axis oriented (Zn-face) hydrothermally grown single crystal ZnO substrates by employing Radio Frequency magnetron sputtering at variable sputtering power densities. Structural and optical properties of the thin films show that at low sputtering power densities, the thin films grow homoepitaxially with a low defect density, while the higher impact energy of depositing atoms and ions at higher sputtering power densities induces damage to the growing film, and a strained, off-axis growth results. The surface morphology of the films reveals a 3D growth mode, and the observed homoepitaxy hence occurs locally inside the grains, i.e. local homoepitaxy.