Journal Article

FZJ-2015-05199

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Surface Termination Conversion during SrTiO$_{3}$ Thin Film Growth Revealed by X-ray Photoelectron Spectroscopy

Bäumer, C. (Corresponding author)FZJ* ; Xu, C.FZJ* ; Gunkel, F.FZJ* ; Raab, N.FZJ* ; Heinen, R.FZJ* ; Köhl, A.FZJ* ; Dittmann, R.FZJ*

2015
Nature Publishing Group London

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Please use a persistent id in citations: http://hdl.handle.net/2128/9034  doi:10.1038/srep11829

Abstract: Emerging electrical and magnetic properties of oxide interfaces are often dominated by the termination and stoichiometry of substrates and thin films, which depend critically on the growth conditions. Currently, these quantities have to be measured separately with different sophisticated techniques. This report will demonstrate that the analysis of angle dependent X-ray photoelectron intensity ratios provides a unique tool to determine both termination and stoichiometry simultaneously in a straightforward experiment. Fitting the experimental angle dependence with a simple analytical model directly yields both values. The model is calibrated through the determination of the termination of SrTiO3 single crystals after systematic pulsed laser deposition of sub-monolayer thin films of SrO. We then use the model to demonstrate that during homoepitaxial SrTiO3 growth, excess Sr cations are consumed in a self-organized surface termination conversion before cation defects are incorporated into the film. We show that this termination conversion results in insulating properties of interfaces between polar perovskites and SrTiO3 thin films. These insights about oxide thin film growth can be utilized for interface engineering of oxide heterostructures. In particular, they suggest a recipe for obtaining two-dimensional electron gases at thin film interfaces: SrTiO3 should be deposited slightly Ti-rich to conserve the TiO2-termination.

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Contributing Institute(s):

1. Elektronische Materialien (PGI-7)
2. JARA-FIT (JARA-FIT)

Research Program(s):

1. 521 - Controlling Electron Charge-Based Phenomena (POF3-521) (POF3-521)

Appears in the scientific report 2015

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Database coverage:
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