Dresden 2011 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 42: Poster I: Progress in Micro- and Nanopatterning: Techniques and Applications (jointly with O); Spins in Organic Materials; Ion Interactions with Nano Scale Materials; Organic Electronics and Photovoltaics; Plasmonics and Nanophotonics (jointly with HL and O); High-k and Low-k Dielectrics (jointly with DF); Organic Thin Films; Nanoengineered Thin Films; Layer Deposition Processes; Layer Properties: Electrical, Optical, and Mechanical Properties; Thin Film Characterisation: Structure Analysis and Composition; Application of Thin Films
DS 42.94: Poster
Mittwoch, 16. März 2011, 15:00–17:30, P1
Preparation and X-Ray standing Wave Measurements of STO/LAO films — •Christoph Schlueter and Jörg Zegenhagen — ESRF, 6 rue Jules Horowitz, BP 220, 38043 Grenoble, CEDEX 9, France
The formation of a quasi-2dimensional electron gas at the interface of SrTiO3 (STO) and LaAlO3 (LAO) attracted considerable attention in recent years.[1] A X-ray standing wave (XSW) and X-Ray Photoelectron Spectroscopy (XPS) experiment is expected to help elucidate details of the electronic and atomic structure at the interface. Samples of high crystallographic quality are needed for these experiments. Samples were grown on (001) oriented STO single crystal substrates. TiO2 termination was obtained by standard methods.[2] The thin films were deposited in a UHV compatible pulsed laser deposition (PLD) chamber using a UV laser (λ=248nm) at sample temperatures of 750 - 820∘C in an oxygen atmosphere of 5*10−5 mbar. For samples held at elevated temperatures for longer times (tempering and/or slow cooling rate) steps were found to bunch by atomic force microscopy (AFM). This is indicative on a significant surface diffusivity at these temperatures. Faster cooling times (1-1.5h) resulted in smooth surfaces with unit cell height steps. AFM and reflectivity data are in reasonable agreement. For even higher cooling rates powder rings prove that parts of the film are badly oriented. Diffraction and XSW experiments indicate the formation of fully strained films.
1. 1. A. Ohtomo et al., Nature 427, no. 6973, (2004): 423-426.
2. G. Koster et al., Appl. Phys. Lett. 73, no. 20 (1998): 2920-2922.