Photoinduced Effects of Ferroelectric Domains in PbZr1-xTixO3 Thin Films as Obtained by Using Piezoresponse Force Microscopy

摘要

Piezoresponse force microscopy (PFM) has been used to investigate the photoinduced effect of ferroelectric domains in PbZr1-xTixO3 (PZT) thin films. In order to perform nondestructive visualization of the highresolution domain structure, we optimized the imaging condition, such as applying a lower voltage than 1.0 Vpp (peak-to-peak voltage). In this study, domain changes were measured before and after illumination on the surface of PZT films by using an UV light emitting diode (LED) source (A = 310 nm) with a focusing lens to investigate the influence of the photoinduced carriers on the ferroelectric polarization. In addition, to investigate the photoinduced effects on the domain distribution, we performed histogram of positive and negative domains before and after UV-light illumination. The illumination with UV light resulted in an increase of the positive domain of the out-of-plane mode. Also, a change in the out-of-plane domain distribution was observed before and after UV illumination. The relaxation of photoinduced changes was monitored by repeated scans within a time range of 20 ~ 60 minutes.