Probing the Interaction Between Ferroelectric Surfaces and Adsorbed Water

Under ambient conditions, all exposed surfaces are covered by a thin layer of adsorbed water, inherently modifying the electrochemical environment. Ferroelectric materials, especially, strongly interact with the polar water molecules, which can influence switching dynamics and the shape, size, and stability of the resulting domains, as well as modulating defect-mediated electrical transport at domain walls, while the water itself can condense in a polarisation-selective manner on the surface.

Here, we present our local studies of the interaction between water and ferroelectric materials, carried out by piezorespose force microcopy, electrostatic force microscopy, and Kelvin probe force microscopy imaging in Pb(Zr0.2Ti0.8)O3 thin films. Our studies address the influence of surface water on polarisation switching dynamics, and the role of polarisation orientation as well as switching/charging history on water adsorption and surface charge dissipation at varying relative humidities at room temperature. We also investigate the growth of ice-like water layers at low temperature and high humidity on ferroelectric thin films, demonstrating a polarisation-dependent control over the water layers at submicron scales. These “nanofluidics” could potentially provide a useful control in catalysis applications.

Finally, we look at the role of relative humidity on the polarisation-dependent asymmetrical nanotribology induced in ferroelectrics as a result of high strain gradients under a scanning probe microscope tip.