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Proceedings Paper

Infrared photodiodes based on Type-II strained layer superlattices
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Paper Abstract

The InAs/GaSb Type II strained layer superlattice (SLS) is promising III-V material system for infrared (IR) devices due to the ability to engineer its bandgap between 3-30 μm and potentially have many advantages over current technologies such as high uniformity smaller leakage current due to reduced Auger recombination which are crucial for large IR focal plane arrays. However, an issue with this material system is that it relies on growth on GaSb substrates. These substrates are significantly more expensive than silicon, used for HgCdTe detectors, lower quality and are only available commercially as 3" diameters. Moreover it has to go through thinning down before it could be hybridized to readout integrated circuits. GaAs substrate is a possible alternative. We report on growth and characterisation of Type-II InAs/GaSb SLS photodiodes grown on GaAs substrates for mid-wave infrared with peak responses of 3.5 μm at 77K and 4.1 μm at 295K. Comparisons with similar structure grown on GaSb substrates show similar structural, optical and electrical characteristics. Broadening of X-ray rocking curves were observed on the structure grown on GaAs substrate. A full width half maximum (FWMH) of 25.2 arc sec. for the superlattice was observed near ~30.4 degree for the structure on GaSb substrate compared to near ~30.4 degree for structure grown on GaAs. However peak responsivity values of ~ 1.9 A/W and ~ 0.7 A/W were measured at 77K and 295K for devices grown on GaAs substrate. Room temperature responsivity suggests that these photodiodes are promising as high temperature IR detectors.

Paper Details

Date Published: 2 October 2008
PDF: 10 pages
Proc. SPIE 7113, Electro-Optical and Infrared Systems: Technology and Applications V, 71130I (2 October 2008); doi: 10.1117/12.802203
Show Author Affiliations
Sankha D. Das, The Univ. of Sheffield (United Kingdom)
Yu Ling Goh, The Univ. of Sheffield (United Kingdom)
Chee Hing Tan, The Univ. of Sheffield (United Kingdom)
John Paul R. David, The Univ. of Sheffield (United Kingdom)
Jean-Baptiste Rodriguez, The Univ. of New Mexico (United States)
Elena A. Plis, The Univ. of New Mexico (United States)
Yagya D. Sharma, The Univ. of New Mexico (United States)
Ha Sul Kim, The Univ. of New Mexico (United States)
Sanjay Krishna, The Univ. of New Mexico (United States)


Published in SPIE Proceedings Vol. 7113:
Electro-Optical and Infrared Systems: Technology and Applications V
David A. Huckridge; Reinhard R. Ebert, Editor(s)

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