Photoinduced Effects of UV illumination on PbZr0.30Ti0.70O3 Thin Films

The photoinduced effects in PbZr0(0.30)Ti(0.70)O(3) (PZT) thin films have been investigated by applying combined measurements with atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), and piezoresponse force microscopy (PFM) imaging techniques. In this study, ferroelectric domains and photoinduced carrier distributions were measured before and after UV illumination and DC bias poling on the film's surface by using an UV light emitting diode (lambda = 310 nm). By analysis of the histogram distributions of the phase signal of the out-of-plane ferroelectric polarization, we observed that the charges trapped on the sample's surface layer by the UV illumination affected the ferroelectric domain patterns, thus changing the orientation of out-of-plane domains. In addition, we observed that because of negatively trapped charges near the film surface, the surface potential shifted to a negative value after UV illumination.