Test pixel and focal plane array fabrication and characterization of N-structure InAs/AlSb/GaSb infrared superlattice detectors

In this thesis, photodetector device production and characterization of InAs/AlSb/GaSb superlattice structures that detect at short and medium wavelengths were carried out. In N structure superlattice designs, AlGaSb barrier layer was also included in the design and three different designs were used: pBin e-SWIR and MWIR, and nBn dual color MWIR/MWIR designs. Within the scope of the study, various steps of fabrication were optimized for test detector and focal plane array (FPA) productions and thus repeatable and homogeneous productions could be made. Test detectors were fabricated using pBin e-SWIR structure, and electro-optical performances with respect to temperature were measured. In e-SWIR, dark current density was measured as 3,9 × 10-6 A/cm2 under ‒0,1 V bias voltage at 125 K, 100% cutoff wavelength was 3,2 μm, and peak quantum efficiency was around 55%. Compared to the literature, the structure's very wide spectral detection range in the SWIR window and its very high electro-optical performance values show the high potential of N-structure designs in the field. Snapshot thermal images were taken from single and dual color MWIR FPAs developed and produced in this study. Cracks in the detector material that occur during cooling are instantly displayed. The electro-optical performance maps and histograms of the pixels of the produced FPAs were examined in detail. Successful infrared imaging was performed on the long wavelength side of the dual color MWIR/MWIR detector.