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Title: Quasi-two-dimensional electron gas at the epitaxial alumina/SrTiO{sub 3} interface: Control of oxygen vacancies

In this paper, we report on the highly conductive layer formed at the crystalline γ-alumina/SrTiO{sub 3} interface, which is attributed to oxygen vacancies. We describe the structure of thin γ-alumina layers deposited by molecular beam epitaxy on SrTiO{sub 3} (001) at growth temperatures in the range of 400–800 °C, as determined by reflection-high-energy electron diffraction, x-ray diffraction, and high-resolution electron microscopy. In situ x-ray photoelectron spectroscopy was used to confirm the presence of the oxygen-deficient layer. Electrical characterization indicates sheet carrier densities of ∼10{sup 13 }cm{sup −2} at room temperature for the sample deposited at 700 °C, with a maximum electron Hall mobility of 3100 cm{sup 2}V{sup −1}s{sup −1} at 3.2 K and room temperature mobility of 22 cm{sup 2}V{sup −1}s{sup −1}. Annealing in oxygen is found to reduce the carrier density and turn a conductive sample into an insulator.
Authors:
; ;  [1] ; ;  [2] ; ; ;  [3] ; ;  [4] ;  [5]
  1. Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)
  2. Department of Chemical Engineering, University of Texas at Austin, Austin, Texas 78712 (United States)
  3. Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States)
  4. Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106 (United States)
  5. IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States)
Publication Date:
OSTI Identifier:
22413227
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 9; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; ANNEALING; CARRIER DENSITY; ELECTRON DIFFRACTION; ELECTRON GAS; ELECTRON MICROSCOPY; ELECTRONS; INTERFACES; LAYERS; MOLECULAR BEAM EPITAXY; STRONTIUM TITANATES; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; TWO-DIMENSIONAL SYSTEMS; VACANCIES; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY