Quantum Well Infrared Photodetectors (QWIPs) are strong competitors to other detector technologies for future third generation thermal imagers. QWIPs have inherent advantages of mature III-V material system and well settled fabrication technology, as well as narrow band photo-response which is an important property facilitating the development of dual-band imagers with low crosstalk. This thesis focuses on the development of long/mid wavelength dual band QWIP focal plane arrays (FPAs) based on the AlGaAs/GaAs material system.
Apart from traditional single band QWIPs, the dual-band operation is achieved by proper design of a bias tunable quantum well structure which has two responsivity peaks at 4.8 and 8.4 um for midwave infrared (MWIR) and longwave infrared (LWIR) atmospheric windows, respectively. The fabricated large format (640x512) FPA has MWIR and LWIR cut-off wavelengths of 5.1 and 8.9 um, and it provides noise equivalent temperature differences (NETDs) of ~ 20 and 32 mK (f/1.5 at 65 K) in these bands, respectively. The employed bias tuning approach for the dual-band operation requires the same fabrication steps established for single band QWIP FPAs, which is an important advantage of the selected method resulting in high-yield, high-uniformity and low-cost. Results are encouraging for fabrication of low cost, large format, and high performance dual band FPAs, making QWIP a stronger candidate in the competition for third generation thermal imagers
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12610936/index.pdf |
| Date | 01 September 2009 |
| Creators | Arslan, Yetkin |
| Contributors | Besikci, Cengiz |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | Access forbidden for 1 year |
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