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

Journal Article · Mon Jul 28 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4891225· OSTI ID:22308532

Choi, Miri; Posadas, Agham B.; O'Hara, Andrew; Seinige, Heidi; Tsoi, Maxim; Rodriguez, Cesar A.; Zollner, Stefan ^[1]; Kellock, Andrew J. ^[2]; Frank, Martin M.; Narayanan, Vijay ^[3]

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1. Department of Physics, New Mexico State University, MSC 3D, P.O. Box 30001, Las Cruces, New Mexico 88003 (United States)
2. IBM Almaden Research Center, San Jose, California 95120 (United States)
3. IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

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.

• OSTI ID: 22308532
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 4 Vol. 116; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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