Influence of the Ar:O2 molar ratio on the piezoresponse and polarization characteristics of megnetron sputtered ZnO thin films

With the same total working pressure, ZnO thin films were prepared on aluminum electrode layers by radio frequency magnetron sputtering at different Ar:O2 molar ratios. The preferred orientation, surface topography and piezoresponse were analyzed using X-ray diffraction (XRD), atom force microscopy (AFM) and piezoresponse force microscopy (PFM). The polarization characteristics of the ZnO grains were studied by vertical PFM (VPFM)and lateral PFM (LPFM) phase diagrams. The results show that the Ar:O2 molar ratio has great influence on the crystal structure and piezoelectric properties of the ZnO thin films, and among the samples, the one deposited at the Ar:O2 molar ratio of 1:1 shows the greatest VPFM amplitude and the best polarization orientation uniformity. ©, 2015, Chinese Ceramic Society. All right reserved.