Structural, optical, and electrical properties of strained La-doped SrTiO3 films
Abstract
The structural, optical, and room-temperature electrical properties of strained La-doped SrTiO3 epitaxial thin films are investigated. Conductive La-doped SrTiO3 thin films with concentration varying from 5 to 25% are grown by molecular beam epitaxy on four different substrates: LaAlO3, (LaAlO3)0.3(Sr2AlTaO6)0.7, SrTiO3, and DyScO3, 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 ∼10−2 to 10−5 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 SrTiO3. 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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 24, 2014
- Source ID
- 10.1063/1.4891225
Entities
People
- Agham Posadas
- Alexander A Demkov
- Andrew O'Hara
- Andrew J. Kellock
- Cesar A. Rodriguez
- Heidi Seinige
- Martin M. Frank
- Maxim Tsoi
- Miri Choi
- Stefan Zollner
- Vijay Narayanan
Organizations
- Air Force Office of Scientific Research
- International Business Machines Corporation (Armonk, NY)
- National Science Foundation
- New Mexico State University
- Semiconductor Research Corporation
- University of Texas at Austin