Impact ionization in AlxGa1−xAsySb1−y avalanche photodiodes
Abstract
Avalanche photodiodes (APDs) have been fabricated in order to determine the impact ionization coefficients of electrons (α) and holes (β) in AlxGa1−xAsySb1−y lattice matched to GaSb for three alloy compositions: (x = 0.40, y = 0.035), (x = 0.55, y = 0.045), and (x = 0. 65, y = 0.054). The impact ionization coefficients were calculated from photomultiplication measurements made on specially designed APDs, which allowed for both pure electron and pure hole injection in the same device. Photo-multiplication measurements were made at temperatures ranging from 77 K to 300 K for all three alloys. A quasi-physical model with an explicit temperature dependence was used to express the impact ionization coefficients as a function of electric-field strength and temperature. For all three alloys, it was found that α < β at any given temperature. In addition, the values of the impact ionization coefficients were found to decrease as the aluminum concentration of the AlGaAsSb alloy was increased. A value between 1.2 and 4.0 was found for β/α, which is dependent on temperature, alloy composition, and electric-field strength.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 21, 2014
- Source ID
- 10.1063/1.4872253
Entities
People
- E. Duerr
- G. Turner
- J. Donnelly
- M. Diagne
- M. Grzesik
- M. Manfra
- R. Bailey
- W. Goodhue
Organizations
- Defense Advanced Research Projects Agency
- Massachusetts Institute of Technology