Regensburg 2019 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 3: Layer Properties: Electronic, Optical and Mechanical Properties
DS 3.6: Vortrag
Montag, 1. April 2019, 10:45–11:00, H39
Local and correlated studies of humidity-mediated ferroelectric thin film surface charge dynamics — •Iaroslav Gaponenko1, Neus Domingo2, Nicolas Stucki3, Albert Verdaguer2, and Patrycja Paruch1 — 1DQMP, University of Geneva, 1211 Geneva, Switzerland — 2ICN2, Campus UAB, 08193 Bellaterra, Spain — 3HES-SO/hepia, 1213 Geneva, Switzerland
Surface water is present on all materials exposed to ambient environmental conditions, modifying the ground state in fundamental studies as well as affecting the operation of bare-chip devices. Due to its polar nature, water strongly interacts with domains and domain walls in ferroelectric materials.
Here, we present a combined Kelvin probe force microscopy (KPFM) and near-ambient pressure x-ray photoelectron spectroscopy (AP-XPS) study of the relative humidity (RH) dependence of the formation and evolution of surface charges on oppositely polarised PZT thin films. AP-XPS measurements show chemical differences on surface adsorbates as well as significant changes in the bulk ionic distribution as a function of both the as-grown polarisation state and after switching. KPFM measurements tracking the dissipation of surface charges confirm that both the initial state of the samples and their switching history have an influence on the electrochemistry and surface charge dynamics as a function of RH. Through these two approaches, we demonstrate the complexity of surface water mediated chemistry and electrochemistry on ferroelectric materials.