Regensburg 2013 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 12: Poster Session II: Functionalized semiconductor nanowires (jointly with HL); Resistive switching (jointly with DF, KR, HL); Thermoelectric materials

DS 12.8: Poster

Montag, 11. März 2013, 17:00–20:00, Poster B1

Transmission X-ray microscopy of resistively switched epitaxial Fe-doped SrTiO3 MIM structures — •Holger Wasmund¹, Annemarie Köhl¹, Peter Guttmann², Katja Henzler², Stephan Werner², Sebastian Schmelzer¹, Regina Dittmann¹, and Rainer Waser¹ — ¹FZ Jülich, PGI-7, Germany — ²HZB, Institute for soft Matter and functional Materials, Germany

There exists strong experimental evidence that the resistance change in transition metal oxides is caused by a valency change on a nanoscale. Transmission X-ray microscopy exhibit the potential of observing bulk spectral information of the sample with a spatial resolution of 25nm unlike other methods which exclusively probe the surface e.g. XPS. One central issue in TXM probe preparation is the sample thickness which should not exceed 100nm. As a first approach we studied polycrystalline STO devices on SiN membranes which were switched in two different resistive states. To analyse epitaxial grown STO devices we prepared SRO|STO|Pt MIM structures on top of NGO substrates with an intermediate sacrifical layer by pulsed laser deposition and sputtered Pt electrodes. A chromium adhesion layer and a carbon film were deposited on top of the stack in order to serve as a carrier foil, followed by a selective etching step of the sarifical layer to release the specimen from the substrate. XAS spectra measurements at the Ti L edge and the Fe L edge for electrode pads in different resistive states were realized at the U41 beamline at Bessy II. We observed significant changes in the Ti spectra which are indications for a valency change in a filament like region.