Dresden 2009 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 2: Dielectric Spectroscopy & Microscopy
DF 2.5: Talk
Monday, March 23, 2009, 12:00–12:20, WIL A317
Investigation of the surface charge density of lithium niobate crystals with scanning force microscopy* — •Florian Johann, Tobias Jungk, Akos Hoffmann, and Elisabeth Soergel — Institute of Physics, University of Bonn, Wegelerstr. 8, 53115 Bonn, Germany
Theoretical calculations of the surface charge density of lithium niobate yield a result of 0.7 C/ m2 for the z-face. It is safe to say that this value can not be true for a real crystal, since this charge density would be high enough to ionize air at a domain boundary. Therefore the real surface charge must be reduced by internal and external compensation mechanisms. The scanning force microscope is a perfect tool to investigate the dependance of the surface charges with respect to temperature, illumination, and humidity. In the end it should be possible to determine an order of magnitude for the really occuring charge density.
*Financial support from the Deutsche Telekom AG is gratefully acknowledged.