Structural and magnetic properties of Co-doped ZnO epitaxial films

Abstract

We examined growth conditions to obtain the best quality epitaxial Co-doped ZnO thin films by the laser MBE deposition technique. The RHEED pattern and XRD analysis showed that the growth mode is layer-by-layer and a single phase of the wurtzite ZnO structure results at the optimum growth condition, that is, laser fluence, oxygen partial pressure and substrate temperature being at 0.45 J/cm 2, 1.0×10 −6 torr and 550 °C, respectively. From AFM measurements, the root mean square value of surface roughness was determined to be about 2 Å. The epitaxial Co-doped ZnO thin films were shown to possess intrinsic ferromagnetic ordering at room temperature.