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MA: Fachverband Magnetismus

MA 32: Magnetic Thin Films III

MA 32.7: Talk

Thursday, March 26, 2009, 11:45–12:00, HSZ 403

Analysis of electronic defect states in lanthanum manganite / strontium titanate heterointerfaces by photovoltage and photoconductivity spectroscopy — •Elke Beyreuther¹, Andreas Thiessen¹, Stefan Grafström¹, Kathrin Dörr², and Lukas M. Eng¹ — ¹Institut für Angewandte Photophysik, Technische Universität Dresden, D-01062 Dresden, Germany — ²Institut für Metallische Werkstoffe, IFW Dresden, D-01171Dresden, Germany

Similar to conventional microelectronic device structures, the performance of all-oxide electronic devices crucially depends on the electronic defect state distribution at the surfaces and interfaces of a given heterostructure. As soon as wide-bandgap oxides are involved, the analysis of the electronic properties becomes a challenge due to low carrier concentrations, which make classical electrical characterization methods fail.

Thus, in the present approach we choose optical techniques such as surface photovoltage and photoconductivity spectroscopy to map the distribution of defect states in heterostructures, consisting of lanthanum manganite (La_0.7Ca_0.3MnO₃, La_0.7Ce_0.3MnO₃) thin films on SrTiO₃ substrates.

Within the framework of a comparative evaluation of our spectra we also discuss the information content and the perspective of the methods applied.