24 January 2011 Gamma-ray irradiation effects on InAs/GaSb-based nBn IR detector
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IR detectors operated in a space environment are subjected to a variety of radiation effects while required to have very low noise performance. When properly passivated, conventional mercury cadmium telluride (MCT)-based infrared detectors have been shown to perform well in space environments. However, the inherent manufacturing difficulties associated with the growth of MCT has resulted in a research thrust into alternative detector technologies, specifically type-II Strained Layer Superlattice (SLS) infrared detectors. Theory predicts that SLS-based detector technologies have the potential of offering several advantages over MCT detectors including lower dark currents and higher operating temperatures. Experimentally, however, it has been found that both p-on-n and n-on-p SLS detectors have larger dark current densities than MCT-based detectors. An emerging detector architecture, complementary to SLS-technology and hence forth referred to here as nBn, mitigates this issue via a uni-polar barrier design which effectively blocks majority carrier conduction thereby reducing dark current to more acceptable levels. Little work has been done to characterize nBn IR detectors tolerance to radiation effects. Here, the effects of gamma-ray radiation on an nBn SLS detector are considered. The nBn IR detector under test was grown by solid source molecular beam epitaxy and is composed of an InAs/GaSb SLS absorber (n) and contact (n) and an AlxGa1-xSb barrier (B). The radiation effects on the detector are characterized by dark current density measurements as a function of bias, device perimeter-to-area ratio and total ionizing dose (TID).
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Vincent M. Cowan, Vincent M. Cowan, Christian P. Morath, Christian P. Morath, Seth M Swift, Seth M Swift, Stephen Myers, Stephen Myers, Nutan Gautam, Nutan Gautam, Sanjay Krishna, Sanjay Krishna, } "Gamma-ray irradiation effects on InAs/GaSb-based nBn IR detector", Proc. SPIE 7945, Quantum Sensing and Nanophotonic Devices VIII, 79451S (24 January 2011); doi: 10.1117/12.873413; https://doi.org/10.1117/12.873413

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