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Impact ionization rate calculations in wide band gap semiconductors

Harrison, D; Abram, RA; Brand, S

Impact ionization rate calculations in wide band gap semiconductors Thumbnail


D Harrison

S Brand


An algorithm for calculating impact ionization rates in the semiclassical Fermi’s Golden Rule approximation which is efficient close to threshold is presented. Electron and hole initiated rates are calculated for three semiconductors with particular band structure characteristics, as are the distributions of the generated carriers. Simple analytic expressions of the form R = A(E−E0)P are fitted to the calculated rates. The role of the matrix elements in influencing the distribution of final states is investigated. In the direct gap materials, they act to significantly enhance the low-q transitions, while in the indirect gap case they have a lesser effect on the distribution. Results for GaAs obtained here and by several other workers are compared and possible causes of the discrepancies examined, including differences in band structure and approximations made in evaluation of the matrix element. It is found that these differences do not influence the rate sufficiently to account for the wider variation between authors, and so it is concluded that differences in the implementation of the rate integration algorithm are the main cause.


Harrison, D., Abram, R., & Brand, S. (1999). Impact ionization rate calculations in wide band gap semiconductors. Journal of Applied Physics, 85(12), 8178-8185.

Journal Article Type Article
Publication Date Jan 1, 1999
Deposit Date Dec 7, 2010
Publicly Available Date Dec 7, 2010
Journal Journal of Applied Physics
Print ISSN 0021-8979
Electronic ISSN 1089-7550
Publisher American Institute of Physics
Peer Reviewed Peer Reviewed
Volume 85
Issue 12
Pages 8178-8185
Publisher URL


Published Journal Article (249 Kb)

Copyright Statement
Copyright (1999) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Harrison, D. and Abram, R.A. and Brand, S. (1999) 'Impact ionization rate calculations in wide band gap semiconductors.', Journal of applied physics., 85 (12). pp. 8178-8185 and may be found at

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