Effects of Ni d-levels on the electronic band structure of NixCd1-xO semiconducting alloys

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • Christopher A. Francis
  • Maribel Jaquez
  • Juan F. Sánchez-Royo
  • Sepher K. V. Farahani
  • Chris F. McConville
  • Jeffrey Beeman
  • Min Ting
  • Oscar D. Dubón
  • Wladek Walukiewicz

Related Research Unit(s)

Detail(s)

Original languageEnglish
Article number185703
Journal / PublicationJournal of Applied Physics
Volume122
Issue number18
Online publishedNov 2017
Publication statusPublished - 14 Nov 2017

Abstract

NixCd1-xO has a ∼3 eV band edge offset and bandgap varying from 2.2 to 3.6 eV, which is potentially important for transparent electronic and photovoltaic applications. We present a systematic study of the electronic band structure of NixCd1-xO alloys across the composition range. Ion irradiation of alloy samples leads to a saturation of the electron concentration associated with pinning of the Fermi level (EF) at the Fermi stabilization energy, the common energy reference located at 4.9 eV below the vacuum level. The composition dependence of the pinned EF allows determination of the conduction band minimum (CBM) energy relative to the vacuum level. The unusually strong deviation of the CBM energy observed from the virtual crystal approximation is explained by a band anticrossing interaction between localized 3d states of Ni and the extended states of the NixCd1-xO alloy host. The resulting band structure explains the dependence between the composition and the electrical and optical properties of the alloys - the rapid reduction of the electron mobility as well as previously observed positive band gap bowing parameter. X-ray photoelectron spectroscopy studies confirm that the L-point valence band maximum in the Cd-rich alloys are unaffected by the interaction with Ni d-states.

Citation Format(s)

Effects of Ni d-levels on the electronic band structure of NixCd1-xO semiconducting alloys. / Francis, Christopher A.; Jaquez, Maribel; Sánchez-Royo, Juan F.; Farahani, Sepher K. V.; McConville, Chris F.; Beeman, Jeffrey; Ting, Min; Yu, Kin M.; Dubón, Oscar D.; Walukiewicz, Wladek.

In: Journal of Applied Physics, Vol. 122, No. 18, 185703, 14.11.2017.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal