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Title: Band structure of germanium carbides for direct bandgap silicon photonics

Abstract

Compact optical interconnects require efficient lasers and modulators compatible with silicon. Ab initio modeling of Ge{sub 1−x}C{sub x} (x = 0.78%) using density functional theory with HSE06 hybrid functionals predicts a splitting of the conduction band at Γ and a strongly direct bandgap, consistent with band anticrossing. Photoreflectance of Ge{sub 0.998}C{sub 0.002} shows a bandgap reduction supporting these results. Growth of Ge{sub 0.998}C{sub 0.002} using tetrakis(germyl)methane as the C source shows no signs of C-C bonds, C clusters, or extended defects, suggesting highly substitutional incorporation of C. Optical gain and modulation are predicted to rival III–V materials due to a larger electron population in the direct valley, reduced intervalley scattering, suppressed Auger recombination, and increased overlap integral for a stronger fundamental optical transition.

Authors:
; ;  [1];  [2];  [3];  [4];  [5];  [6];  [7];  [8]
  1. Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
  2. Rigetti Quantum Computing, 775 Heinz Avenue, Berkeley, California 94710 (United States)
  3. Honeywell UOP, Des Plaines, Illinois 60016 (United States)
  4. Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
  5. Department of Chemistry, Syracuse University, Syracuse, New York 13244 (United States)
  6. Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
  7. Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China)
  8. Institute of Physics, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)
Publication Date:
OSTI Identifier:
22597686
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COMPUTERIZED SIMULATION; DEFECTS; DENSITY FUNCTIONAL METHOD; ELECTRONS; GAIN; GERMANIUM CARBIDES; LASERS; METHANE; REDUCTION; SCATTERING; SILICON

Citation Formats

Stephenson, C. A., E-mail: cstephe3@nd.edu, Stillwell, R. A., Wistey, M. A., O'Brien, W. A., Penninger, M. W., Schneider, W. F., Gillett-Kunnath, M., Zajicek, J., Yu, K. M., and Kudrawiec, R. Band structure of germanium carbides for direct bandgap silicon photonics. United States: N. p., 2016. Web. doi:10.1063/1.4959255.
Stephenson, C. A., E-mail: cstephe3@nd.edu, Stillwell, R. A., Wistey, M. A., O'Brien, W. A., Penninger, M. W., Schneider, W. F., Gillett-Kunnath, M., Zajicek, J., Yu, K. M., & Kudrawiec, R. Band structure of germanium carbides for direct bandgap silicon photonics. United States. doi:10.1063/1.4959255.
Stephenson, C. A., E-mail: cstephe3@nd.edu, Stillwell, R. A., Wistey, M. A., O'Brien, W. A., Penninger, M. W., Schneider, W. F., Gillett-Kunnath, M., Zajicek, J., Yu, K. M., and Kudrawiec, R. 2016. "Band structure of germanium carbides for direct bandgap silicon photonics". United States. doi:10.1063/1.4959255.
@article{osti_22597686,
title = {Band structure of germanium carbides for direct bandgap silicon photonics},
author = {Stephenson, C. A., E-mail: cstephe3@nd.edu and Stillwell, R. A. and Wistey, M. A. and O'Brien, W. A. and Penninger, M. W. and Schneider, W. F. and Gillett-Kunnath, M. and Zajicek, J. and Yu, K. M. and Kudrawiec, R.},
abstractNote = {Compact optical interconnects require efficient lasers and modulators compatible with silicon. Ab initio modeling of Ge{sub 1−x}C{sub x} (x = 0.78%) using density functional theory with HSE06 hybrid functionals predicts a splitting of the conduction band at Γ and a strongly direct bandgap, consistent with band anticrossing. Photoreflectance of Ge{sub 0.998}C{sub 0.002} shows a bandgap reduction supporting these results. Growth of Ge{sub 0.998}C{sub 0.002} using tetrakis(germyl)methane as the C source shows no signs of C-C bonds, C clusters, or extended defects, suggesting highly substitutional incorporation of C. Optical gain and modulation are predicted to rival III–V materials due to a larger electron population in the direct valley, reduced intervalley scattering, suppressed Auger recombination, and increased overlap integral for a stronger fundamental optical transition.},
doi = {10.1063/1.4959255},
journal = {Journal of Applied Physics},
number = 5,
volume = 120,
place = {United States},
year = 2016,
month = 8
}