DocumentCode :
1529204
Title :
The impact of a large bandgap drift region in long-wavelength metamorphic photodiodes
Author :
Jang, J.H. ; Cueva, G. ; Dumka, D.C. ; Hoke, W.E. ; Lemonias, P.J. ; Fay, P. ; Adesida, I.
Author_Institution :
Dept. of Electr. & Comput. Eng., Illinois Univ., Urbana, IL, USA
Volume :
13
Issue :
10
fYear :
2001
Firstpage :
1097
Lastpage :
1099
Abstract :
A comparative study of two types of metamorphic double heterojunction long-wavelength photodiodes on GaAs substrates is performed in terms of their bandwidths and responsivities. A p-i-i-n heterostructure with a large bandgap drift layer (I-InAlAs) at the cathode end of the photoabsorption region (i-InGaAs) is compared experimentally and theoretically to a p-i-n structure without a drift layer. Both types of photodiodes were fabricated using an InGaAs-InGaAlAs-InAlAs double heterostructure design to simultaneously achieve high bandwidths and high responsivities. The inclusion of an I-InAlAs drift region resulted in p-i-i-n photodiodes with larger bandwidths than p-i-n photodiodes with the same areas, or conversely a p-i-i-n photodiode can be made larger than a comparable p-i-n photodiode, but achieve the same bandwidth. Therefore, p-i-i-n photodiodes provide larger optical fiber alignment tolerances and better coupling efficiency than p-i-n photodiodes with the same bandwidths, p-i-i-n photodiodes with 10-μm-diameter optical windows typically exhibited low dark currents of 500 pA at 5-V bias, responsivities of 0.6 A/W, and a -3-dB bandwidth of 38 GHz for 1.55-μm operation.
Keywords :
III-V semiconductors; cathodes; dark conductivity; gallium arsenide; indium compounds; optical communication equipment; optical design techniques; optical fabrication; photodetectors; photodiodes; 1.55 mum; 10 mum; 38 GHz; 5 V; 500 pA; GaAs; GaAs substrates; InGaAs-InGaAlAs-InAlAs; InGaAs-InGaAlAs-InAlAs double heterostructure; cathode end; coupling efficiency; large bandgap drift region; long-wavelength metamorphic photodiodes; metamorphic double heterojunction long-wavelength photodiodes; optical fiber alignment tolerances; p-i-i-n heterostructure; p-i-i-n photodiodes; p-i-n structure; photoabsorption region; responsivities; Bandwidth; Cathodes; Dark current; Gallium arsenide; Heterojunctions; Indium gallium arsenide; Indium phosphide; PIN photodiodes; Photonic band gap; Substrates;
fLanguage :
English
Journal_Title :
Photonics Technology Letters, IEEE
Publisher :
ieee
ISSN :
1041-1135
Type :
jour
DOI :
10.1109/68.950747
Filename :
950747
Link To Document :
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