Importance of substrate rotation speed on the growth of homogeneous ZnO thin films by reactive sputtering

Undoped zinc oxide (ZnO) thin films were reactively deposited on soda-lime glass substrates by radio frequency (rf) sputtering at room temperature. We have studied the importance of substrate rotation speed on the structural, optical and morphological properties. The rotation speeds used were 0, 20, 40, 60, and 80 rpm. The XRD measurements confirmed that films were grown with (002) plane preferential orientation. The average transmittance was above 90% in the UV-vis region. The SEM images revealed that films deposited with substrate rotation are more homogeneous than the films deposited without rotation.