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Title: Structural, optical, and electrical properties of strained La-doped SrTiO{sub 3} films

The structural, optical, and room-temperature electrical properties of strained La-doped SrTiO{sub 3} epitaxial thin films are investigated. Conductive La-doped SrTiO{sub 3} thin films with concentration varying from 5 to 25% are grown by molecular beam epitaxy on four different substrates: LaAlO{sub 3}, (LaAlO{sub 3}){sub 0.3}(Sr{sub 2}AlTaO{sub 6}){sub 0.7}, SrTiO{sub 3}, and DyScO{sub 3}, which result in lattice mismatch strain ranging from −2.9% to +1.1%. We compare the effect of La concentration and strain on the structural and optical properties, and measure their effect on the electrical resistivity and mobility at room temperature. Room temperature resistivities ranging from ∼10{sup −2} to 10{sup −5} Ω cm are obtained depending on strain and La concentration. The room temperature mobility decreases with increasing strain regardless of the sign of the strain. The observed Drude peak and Burstein-Moss shift from spectroscopic ellipsometry clearly confirm that the La addition creates a high density of free carriers in SrTiO{sub 3}. First principles calculations were performed to help understand the effect of La-doping on the density of states effective mass as well as the conductivity and DC relaxation time.
Authors:
; ; ; ; ;  [1] ; ;  [2] ;  [3] ; ;  [4]
  1. Department of Physics, The University of Texas at Austin, Austin, Texas 78712 (United States)
  2. Department of Physics, New Mexico State University, MSC 3D, P.O. Box 30001, Las Cruces, New Mexico 88003 (United States)
  3. IBM Almaden Research Center, San Jose, California 95120 (United States)
  4. IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States)
Publication Date:
OSTI Identifier:
22308532
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 4; Other Information: (c) 2014 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; ALUMINATES; CARRIER MOBILITY; CRYSTAL DEFECTS; DOPED MATERIALS; DYSPROSIUM COMPOUNDS; EFFECTIVE MASS; ELECTRIC CONDUCTIVITY; ELLIPSOMETRY; LANTHANUM COMPOUNDS; MOLECULAR BEAM EPITAXY; OPTICAL PROPERTIES; OXYGEN COMPOUNDS; RELAXATION TIME; SCANDIUM COMPOUNDS; STRAINS; STRONTIUM TITANATES; SUBSTRATES; TANTALATES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS