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Proceedings Paper

Band engineering of infrared avalanche photodiodes for improved impact ionization coefficient ratios
Author(s): Christoph H. Grein; Michael E. Flatte; Henry Ehrenreich
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Paper Abstract

We model the effects of the electronic band structure on hole- and electron-initiated impact ionization coefficients. Calculations for bulk alloy AlGaSb avalanche photodiodes with alloy compositions near the resonance between the energy gap and the spin-orbit splitting reveal that the hole- to electron-impact ionization coefficient ratio shows no enhancement at high electric fields. This is due to carrier heating spreading the hole distribution in the split-off band. However, an enhancement due to the resonance in the band structure is predicted for weak fields. A strategy to extend this type of an enhancement to high fields in a superlattice involves band engineering the superlattice to place flat bands approximately one energy gap below the top of the valence band. This prevents hot holes from spreading in energy and hence gives rise to strong hole-initiated impact ionization and a large hole- to electron-impact ionization coefficient ratio. Quantitative results are presented for a mid-infrared InAs/GaInSb/AlSb superlattice.

Paper Details

Date Published: 12 November 2001
PDF: 6 pages
Proc. SPIE 4454, Materials for Infrared Detectors, (12 November 2001); doi: 10.1117/12.448176
Show Author Affiliations
Christoph H. Grein, Univ. of Illinois/Chicago (United States)
Michael E. Flatte, Univ. of Iowa (United States)
Henry Ehrenreich, Harvard Univ. (United States)

Published in SPIE Proceedings Vol. 4454:
Materials for Infrared Detectors
Randolph E. Longshore, Editor(s)

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