Growth and Fabrication of Multi-Quantum Well Infrared Photodetectors
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Total Pages | : 0 |
Release | : 2000 |
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A majority of infrared sensors used for imaging arrays operating in the long-wavelength infrared region between lambda = 8-12 micrometers are based on HgCdTe. This material system is unable to satisfy all of the requirements that are imposed by modern applications. Structural difficulties due to poor uniformity, high defect densities, and weak bond strengths cause difficulties in manufacturing large infrared focal plane array cameras. As an alternative, quantum well infrared photodetectors (QWIPs) utilizing intersubband absorption between GaAs wells and AlGaAs barriers were perfected. These QWIPs possess better uniformity in comparison to HgCdTe detectors, and QWIP imaging arrays have recently become commercially available. However, the responsivity of GaAs/AlGaAs QWIPs is still lower than HgCdTe detectors. In order to further improve the responsivity of QWIP detectors, the development of QWIPs with wells or barriers of OaInAsP instead of MOaAs has been developed.