Berlin 2012 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 13: Poster II
DF 13.2: Poster
Mittwoch, 28. März 2012, 15:00–17:30, Poster E
Complex Impedance Model for Metal/Amorphous Semiconductor/Semiconductor (MASS) heterostructures — •Julian Alexander Amani, Tristan Koppe, Marc Brötzmann, Hans Hofsäss, and Ulrich Vetter — Georg-August-Universität Göttingen, II. Physikalisches Institut, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
A complex impedance model for MASS heterostructures is developed and compared with voltage dependent impedance spectroscopy measurements of the metal/ta-C/Si system.
The dominant dc conduction process of ta-C is hopping of carriers and the ac conductivity follows the “universal power law” σ∝ωs with s≈0.8. Hence, ta-C is an exemplary disordered material enabling us to investigate the dielectric properties of this material class.
An equivalent circuit considering the dielectric properties and voltage dependence of an disordered material is presented and compared with complex impedance measurements of ta-C.
Metal/ta-C/Si systems with weakly doped silicon substrates show a rectifying behaviour. Adding a depletion layer equivalent circuit to the model gives a good agreement with the data obtained for measurements of those samples.