Effect of growth induced (non)stoichiometry on the structure, dielectric response, and thermal conductivity of SrTiO 3 thin films

E. Breckenfeld, R. Wilson, J. Karthik, A. R. Damodaran, D. G. Cahill, L. W. Martin

Research output: Contribution to journalArticle

Abstract

We report dramatic variations in cation stoichiometry in SrTiO 3 thin films grown via pulsed laser deposition and the implications of this nonstoichiometry for structural, dielectric, and thermal properties. The chemical composition of SrTiO 3 thin films was characterized via X-ray photoelectron spectroscopy and Rutherford backscattering spectrometry. These studies reveal that deviations in laser fluence and deposition geometry can result in deviations of cation stoichiometry as large as a few percent. Additionally, X-ray diffraction was used to probe structural evolution and revealed an asymmetric strain relaxation mechanism in which films possessing Sr-excess undergo relaxation before those possessing Sr-deficiency. Furthermore, the dielectric constant decreases and the loss tangent increases with increasing nonstoichiometry with intriguing differences between Sr-excess and -deficiency. Thermal conductivity is also found to be sensitive to nonstoichiometry, with Sr-excess and -deficiency resulting in 65% and 35% reduction in thermal conductivity, respectively. These trends are explained by the expected defect structures.

Original languageEnglish (US)
Pages (from-to)331-337
Number of pages7
JournalChemistry of Materials
Volume24
Issue number2
DOIs
StatePublished - Jan 24 2012

Keywords

  • dielectric
  • pulsed laser deposition
  • SrTiO
  • thermal conductivity
  • thin films

ASJC Scopus subject areas

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

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