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Proceedings Paper

Avalanche photodetector in the GaSb/AlSb/InAs material system by molecular beam epitaxy
Author(s): Xiao-Chang Cheng; Thomas C. McGill
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Paper Abstract

GaSb/AlSb/InAs is an attractive system for making low noise avalanche photodetectors (APD) due to possible resonant enhancement of hole impact ionization in AlxGa1-xSb and potential enhancement of electron impact ionization in GaSb/AlSb superlattices. We have employed molecular beam epitaxy (MBE) to fabricate device structures so that these effects could be further explored. The devices were grown on GaSb substrates and incorporated a p-n+ one sided abrupt junction. The p- multiplication region consisted of either bulk Al0.04Ga0.96Sb or 10 periods of alternating, 300 angstrom thick GaSb and AlSb layers. A short period, selectively doped InAs/AlSb superlattice was used as the n+ layer. Dark current suppression in these devices was found to be largely dependent on the InAs/AlSb superlattice configuration and the resulting band offset at the p-n+ heterojunction. Notably, for devices with a 0.6 micrometer Al0.04Ga0.96Sb multiplication region and an optimized InAs/AlSb superlattice, an avalanche break down voltage of 13 V was observed. The dark current density for this device was 6 A/cm2 at a multiplication factor of 10. Devices with GaSb/AlSb superlattice multiplication regions exhibited a higher breakdown voltage (18.5 V) and a lower dark current density (0.4 A/cm2) at comparable gain. Impact ionization rates in Al0.04Ga0.96Sb were studied by using 781 nm and 1645 nm laser light. The results were consistent with enhancement of hole impact ionization in Al0.04Ga0.96Sb.

Paper Details

Date Published: 7 April 1999
PDF: 11 pages
Proc. SPIE 3629, Photodetectors: Materials and Devices IV, (7 April 1999); doi: 10.1117/12.344563
Show Author Affiliations
Xiao-Chang Cheng, California Institute of Technology (United States)
Thomas C. McGill, California Institute of Technology (United States)


Published in SPIE Proceedings Vol. 3629:
Photodetectors: Materials and Devices IV
Gail J. Brown; Manijeh Razeghi, Editor(s)

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