Conduction band-edge d-states in high-k dielectrics due to Jahn-Teller term splittings

G. Lucovsky, C. C. Fulton, Y. Zhang, J. Luning, L. Edge, J. L. Whitten, R. J. Nemanich, D. G. Schlom, V. V. Afanase'V

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

X-ray absorption spectroscopy (XAS) is used to study conduction band edge electronic structure of high-k transition metal (TM) and trivalent lanthanide series rare earth (RE) oxide dielectrics. Empty TM/RE d-states are studied by intra-atomic transitions originating in core level spin-orbit split p-states, and conduction band states are studied in inter-atomic transitions which originate in the oxygen atom 1s core level state. In non-crystalline Zr and Hf silicate alloys, the local bonding symmetry, or crystal field splits these d-states into doubly and triply degenerate features. In nano-crystalline oxides, there are additional d-state splittings due to contributions of more distant neighbors that completely remove d-state degeneracies via the Jahn-Teller effect mechanism. This gives rise to highly localized band edge states that are electronically active in photoconductivity, internal photoemission, and act as bulk traps in metal oxide semiconductor (MOS) devices.

Original languageEnglish (US)
Pages (from-to)129-135
Number of pages7
JournalThin Solid Films
Volume486
Issue number1-2
DOIs
StatePublished - Aug 22 2005
Externally publishedYes

    Fingerprint

Keywords

  • Band edge d-states
  • Bulk trapping
  • Complex oxides
  • Jahn-Teller term splittings
  • Localized band edge states
  • Transition metal/rare earth oxides

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

Cite this

Lucovsky, G., Fulton, C. C., Zhang, Y., Luning, J., Edge, L., Whitten, J. L., Nemanich, R. J., Schlom, D. G., & Afanase'V, V. V. (2005). Conduction band-edge d-states in high-k dielectrics due to Jahn-Teller term splittings. Thin Solid Films, 486(1-2), 129-135. https://doi.org/10.1016/j.tsf.2004.11.233