Characterization of MWIR quantum well infrared photodetectors imaging sensor arrays on InP substrates

Date

2023-9-7

Author

Tanış, Onur

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QWIP (Quantum Well Infrared Photodetector) technology has been researched for over 30 years to create a strong alternative to low bandgap material-based IR (Infrared) technologies. However, low conversion efficiency of QWIPs based on standard material system has delayed the actual potential of this technology. The emergence of the InP based QWIP FPAs (Focal Plane Arrays) has great potential to make QWIP technology attractive again. InP/InxGa1-xAs based QWIP FPAs with high indium mole fraction can reach conversion efficiency as high as 70% in the MWIR (Mid-wave Infrared) band with the ability of sensing of normal radiation which allows utilization of high performance QWIP based FPAs for low background and high-speed applications. In other respects, an FPA must have extra qualifications. Today’s new generation FPAs need new features. These can be categorized as very high uniformity, operability, stability, correctability, scalability, and manufacturability with low pitch. In the scope of the thesis work, InP/In0.85Ga0.15As and InP/InAs based diffraction-grating free QWIP FPAs with 640x512 format and 15 μm pitch were characterized. InP/In0.85Ga0.15As based FPA exhibited mean NETD (Noise Equivalent Temperature Difference) of 20.2 mK at 20 ms integration time and InP/InAs based FPA demonstrated 27.8 mK NETD at 10 ms integration time. Although both designs have strained lattice structure, FPAs yielded very high uniformity. The absence of the optical coupler removes a challenging fabrication step. Mature fabrication processes of the III-V material system ease the production. Widely accessible InP substrates make this technology affordable and reachable.

Subject Keywords

QWIP, FPA, MWIR, Infrared, InP

URI

https://hdl.handle.net/11511/105583

Collections

Graduate School of Natural and Applied Sciences, Thesis