First-principles calculations for Er impurities in Si

ORAL

Abstract

Erbium-doped Si is a promising material for the development of silicon-based light sources that can interface with CMOS technology, optical fiber, and spin centers for quantum computing. Using density functional theory with a screened hybrid functional we examine the structural and electronic properties of Er(III) impurities in Si, focusing on the site preference and the Er effects on the electrical properties of the Si host. We find that Er is stable either at the tetrahedral intersitital site or at the substitutional site, depending on the Fermi-level position; Er sitting at the hexagonal interstitial site is higher in energy at all Fermi levels, in agreement with experimental observations. In p-type Si, i.e., for Fermi levels near the valence band, Er prefers the tetrahedral interstitial site and acts as a donor. In n-type Si, i.e., for Fermi levels near the conduction band, Er prefers the substitutional site and acts as an acceptor. We will also discuss the impurity-to-band optical transitions determined from calculated configuration coordinate diagrams.

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Authors

  • Lars Bjaalie

    Materials Department, University of California, Santa Barbara

  • Lars Ismer

    Materials Department, University of California, Santa Barbara

  • Anderson Janotti

    University of California, Santa Barbara, Materials Department, University of California Santa Barbara, Materials Department, University of California, Santa Barbara, Materials Department, University of California at Santa Barbara

  • C.G. Van de Walle

    Materials Department, University of California, Santa Barbara, Materials Department, University of California Santa Barbara, University of California, Santa Barbara, Materials Department, University of California Santa Barbara, CA 93106-5050, Materials Department, University of California at Santa Barbara, Materials Department, University of California, Santa Barbara, California, CA