Surface screening of written ferroelectric domains in ambient conditions

Abstract

We have combined Piezoresponse Force Microscopy and Kelvin Probe Force Microscopy (KPFM) to study screening charge dynamics in written domains on PbZr0.2Ti0.8O3 (PZT) thin film surfaces under a controlled environment and at variable temperature. The screening dynamics decayed exponentially on a timescale of tens of minutes, consistently with what we expected for water-mediated surface diffusion of ionic species. Variable-temperature KPFM measurements showed variations in surface potential due to temporary unbalanced surface screening charges. Low humidity experiments revealed gradual incorporation of positive charges onto the surface, even in a non-reactive environment (N2), as well as deceleration of the screening dynamics upon reversal of the temperature variation. Our work may serve as a guide for future studies on the dynamics and nature of adsorbates on polarized PZT thin films.