Band alignment of epitaxial SrTiO{sub 3} thin films with (LaAlO{sub 3}){sub 0.3}-(Sr{sub 2}AlTaO{sub 6}){sub 0.7} (001)

Journal Article · Mon Sep 28 00:00:00 EDT 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4932063· OSTI ID:22482162

Comes, Ryan B.; Chambers, Scott A. ^[1]; Xu, Peng; Jalan, Bharat ^[2]

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1. Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)
2. Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

SrTiO{sub 3} (STO) epitaxial thin films and heterostructures are of considerable interest due to the wide range of functionalities they exhibit. The alloy perovskite (LaAlO{sub 3}){sub 0.3}-(Sr{sub 2}AlTaO{sub 6}){sub 0.7} (LSAT) is commonly used as a substrate for these material structures due to its structural compatibility with STO and the strain-induced ferroelectric response in STO films grown on LSAT. However, surprisingly little is known about the electronic properties of the STO/LSAT interface despite its potentially important role in affecting the overall electronic structure of system. We examine the band alignment of STO/LSAT heterostructures using x-ray photoelectron spectroscopy for epitaxial STO films deposited using two different molecular beam epitaxy approaches. We find that the valence band offset ranges from +0.2(1) eV to −0.2(1) eV depending on the film surface termination. From these results, we extract a conduction band offset from −2.4(1) eV to −2.8(1) eV, indicating that the conduction band edge is more deeply bound in STO and that LSAT will not act as a sink or trap for electrons in the supported film or multilayer.

• OSTI ID: 22482162
• Journal Information: Applied Physics Letters, Vol. 107, Issue 13; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
ALUMINATES
DEPOSITS
ELECTRONIC STRUCTURE
FERROELECTRIC MATERIALS
INTERFACES
LANTHANUM COMPOUNDS
LAYERS
MOLECULAR BEAM EPITAXY
PEROVSKITE
POTENTIALS
SINKS
STRAINS
STRONTIUM TITANATES
SUBSTRATES
SURFACES
THIN FILMS
TRAPS
VALENCE
X-RAY PHOTOELECTRON SPECTROSCOPY