Structure and piezoelectricity properties of V-doped ZnO thin films fabricated by sol-gel method

Abstract

Vanadium doped (2.5 at%) ZnO piezoelectric thin films were synthesized on Pt/Ti/SiO2/Si by sol-gel technology. The effects of annealing process on the structure and piezoelectric properties of films were studied. The crystal structure and micro morphology were analyzed by X-ray diffractometer (XRD) and scanning electron microscope (SEM) respectively. The results showed that V-doped ZnO thin films were oriented in (002) direction to some extent. With the increasing of annealing temperature or time, grain size of the film increased, and the density decreased obviously. The piezoelectric properties were measured by piezoresponse force microscopy (PFM) method. As the annealing temperature or time increased, the piezoelectric performance of V-doped ZnO thin film firstly increased and then decreased. The piezoelectric coefficient d33 of V-doped ZnO thin film annealed at 600 °C for 45min followed by 700 °C for 30min was 240 pm/V. Compared with other preparation methods, the sol-gel improved the piezoelectric performance of V-doped ZnO thin film due to the more sufficient and homogeneous doping.