Dopant ion size and electronic structure effects on transparent conducting oxides. Sc-doped CdO thin films grown by MOCVD

Shu Jin, Yu Yang, Julia E. Medvedeva, John R. Ireland, Andrew W. Metz, Jun Ni, Carl R. Kannewurf, Arthur J. Freeman, Tobin J. Marks

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A series of Sc-doped CdO (CSO) thin films have been grown on both amorphous glass and single-crystal MgO(100) substrates at 400§C by MOCVD. Both the experimental data and theoretical calculations indicate that Sc3+ doping shrinks the CdO lattice parameters due to its relatively small six-coordinate ionic radius, 0.89 Å, vs 1.09 Å for Cd2+. Conductivities as high as 18100 S/cm are achieved for CSO films grown on MgO(100) at a Sc doping level of 1.8 atom %. The CSO thin films exhibit an average transmittance >80% in the visible range. Sc3+ doping widens the optical band gap from 2.7 to 3.4 eV via a Burstein-Moss energy level shift, in agreement with the results of band structure calculations within the sX-LDA (screened-exchange local density approximation) formalism. Epitaxial CSO films on single-crystal MgO(100) exhibit significantly higher mobilities (up to 217 cm2/(V·s)) and carrier concentrations than films on glass, arguing that the epitaxial CSO films possess fewer scattering centers and higher doping efficiencies due to the highly textured microstructure. Finally, the band structure calculations provide a microscopic explanation for the observed dopant size effects on the structural, electronic, and optical properties of CSO.

Original languageEnglish
Pages (from-to)13787-13793
Number of pages7
JournalJournal of the American Chemical Society
Issue number42
Publication statusPublished - Oct 27 2004


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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