Dual and single color mid-wavelength infrared quantum well photodetectors

Kaldırım, Melih
Quantum Well Infrared Photodetector (QWIP) technology is promising for the development of large format low cost single and dual/multi color infrared sensor arrays. Thanks to the mature III-V semiconductor technology, QWIP focal plane arrays (FPAs) provide high uniformity and excellent noise equivalent temperature difference (NETD) in both long wavelength infrared (LWIR 8-12 m) and mid wavelength infrared (MWIR 3-5 m) bands. This thesis work focuses on the development of large format single and dual color MWIR QWIP FPAs. For single band MWIR detection, we report QWIP FPAs on InP substrate as an alternative to the GaAs based MWIR QWIPs suffering from the degrading effects of lattice mismatched epitaxy. In the course of this work, epitaxial growth conditions of the device structure were optimized and 640×512 AlInAs/InGaAs QWIP FPAs on InP substrate have been fabricated yielding NETD of 22 mK (f/1.5) and background limited performance (BLIP) temperature as high as 115 K In the second part, we report the first voltage tunable 640×512 dual color MWIR QWIP FPA. After optimizing epitaxial growth of AlGaAs/InGaAs material system, we have designed and implemented the device structure to yield voltage tunable spectral response in two different windows in the MWIR band. The FPA provides NETDs of 60 and 30 mK (f/1.5) in colors 1 and 2. The results are very encouraging for the development of low cost dual/multi color FPAs since our approach utilizes one In bump per pixel allowing fabrication of dual color FPAs with the same process steps for single color FPAs.


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Eker, Süleyman Umut; Beşikci, Cengiz; Department of Electrical and Electronics Engineering (2010)
Excellent uniformity and mature material properties of Quantum Well Infrared Photodetectors (QWIPs) have allowed the realization of large format, low cost staring focal plane arrays (FPAs) in various thermal imaging bands. AlGaAs/InGaAs and AlGaAs/GaAs materials systems have been the standard systems for the construction of mid-wavelength infrared (MWIR) and long-wavelength (LWIR) QWIPs. However AlGaAs/GaAs QWIP FPAs suffer from low quantum and conversion efficiencies under high frame rate (low integration ...
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Citation Formats
M. Kaldırım, “Dual and single color mid-wavelength infrared quantum well photodetectors,” M.S. - Master of Science, Middle East Technical University, 2008.