Demonstration of Mid-Wave Type-II Superlattice InAs/GaSb Single Pixel Barrier Detector With GaAs Immersion Lens

Mid-wave infrared technology is dominated by HgCdTe ternary alloy. As of now, InAs/GaSb type-II superlattice has shown the theoretical potential to compete with HgCdTe. Type-II superlattice InAs/GaSb technology is under development, where proper detector's architecture must be considered as one of the most important steps in terms of performance improvement. The letter presents the performance of the type-II superlattice InAs/GaSb with bulk AlGaSb barrier, mesa type nBn detectors operated under higher operation temperature condition (>200 K) with 50% cutoff wavelength ~5.1 μm at 230 K. The 1.1-mm-thick GaAs substrate was converted into immersion lens to limit the influence of the defects occurring during growth on GaAs substrate and to increase detectivity, ~10
¹⁰
cmHz
^1/2
/W at 230 K, under reverse bias 200 mV and ~3 × 10
⁹
cmHz
^1/2
/W at 300 K, under 400 mV. Presented results are higher than nBn architectures with the same and slightly higher cutoff wavelength grown on GaAs without immersion lens and GaSb substrates.