Interaction of oxygen vacancies in yttrium germanates

Hao Wang, Alexander I. Chroneos, Athanasios Dimoulas Dimoulas, Udo Schwingenschlögl

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10 Scopus citations

Abstract

Forming a good Ge/dielectric interface is important to improve the electron mobility of a Ge metal oxide semiconductor field-effect transistor. A thin yttrium germanate capping layer can improve the properties of the Ge/GeO 2 system. We employ electronic structure calculations to investigate the effect of oxygen vacancies in yttrium-doped GeO 2 and the yttrium germanates Y 2Ge 2O 7 and Y 2GeO 5. The calculated densities of states indicate that dangling bonds from oxygen vacancies introduce in-gap states, but the system remains insulating. However, yttrium-doped GeO 2 becomes metallic under oxygen deficiency. Y-doped GeO 2, Y 2Ge 2O 7 and Y 2GeO 5 are calculated to be oxygen substoichiometric under low Fermi energy conditions. The use of yttrium germanates is proposed as a way to effectively passivate the Ge/dielectric interface. This journal is © 2012 the Owner Societies.
Original languageEnglish (US)
Pages (from-to)14630
JournalPhysical Chemistry Chemical Physics
Volume14
Issue number42
DOIs
StatePublished - 2012

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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