Mid-wavelength high operating temperature barrier infrared detector and focal plane array

Abstract

We analyze and compare different aspects of InAs/InAsSb and InAs/GaSb type-II superlattices for infrared detector applications and argue that the former is the most effective when implemented for mid-wavelength infrared detectors. We then report results on an InAs/InAsSb superlattice based mid-wavelength high operating temperature barrier infrared detector. At 150 K, the 50% cutoff wavelength is 5.37 μm, the quantum efficiency at 4.5 μm is ∼52% without anti-reflection coating, the dark current density under −0.2 V bias is 4.5 × 10−5 A/cm2, and the dark-current-limited and the f/2 black-body (300 K background in 3–5 μm band) specific detectivities are 4.6 × 1011 and 3.0 × 1011 cm-Hz1/2/W, respectively. A focal plane array made from the same material exhibits a mean noise equivalent differential temperature of 18.7 mK at 160 K operating temperature with an f/2 optics and a 300 K background, demonstrating significantly higher operating temperature than InSb.

InAs/InAsSb Strained-Layer Superlattice Mid-Wavelength Infrared Detector for High-Temperature Operation

“…In Figure 6, the absorption efficiency spectra at 78 K correspond to L = 4.8 and 5.5 µm and the spectrum when L = 4.8 µm fits reasonably well with the quantum efficiency spectrum measured at 80 K. Moreover, when the temperature is increased from 80 to 140 K, L increases from 4.8 µm to 5.5 µm, respectively. While this is one straightforward way to explain the QE dependence on temperature, there could be other effects leading to the same observation such as variation in the barrier band alignment to the absorber with temperature and recombination of trapped holes at the interfaces [4].…”

“…This FPA also The dark current and quantum efficiency of the detector reported in this paper are comparable to similar InAs/InAsSb SLS detectors recently reported in the literature. Ting et al [4] have reported an InAs/InAsSb SLS nBn detector with a quantum efficiency of~52% and dark current of 9.6 × 10 −5 A/cm 2 (a factor of~4.5 higher than Rule 07) at~157 K. With a detailed analysis of dark current characteristics, Rhiger et al [30] have reported a similar InAs/InAsSb SLS nBn detector exhibiting a dark current 5 times higher than Rule 07. Furthermore, a comprehensive review of antimony-based detectors has been reported by Rogalski et al [2] With this level of dark current performance and external quantum efficiency >50%, it can be predicted that SLS detectors are well within the reach of performance of InSb detectors but at high temperatures, promising as a candidate for HOT detectors.…”

“…One class of materials that has the potential to do just that are III-V, antimony-based, strained-layer superlattices [2] (SLSs), which have already shown impressive results. HOT [1,3] capability has been the primary goal in the mid-wavelength infrared (MWIR) band and a few demonstrations [4] have been already reported. Research groups have explored different detector architectures (nBn [5], nBp [6], pBp [7], XBn [8], CBIRDs [9] etc.)…”

“…and pixel geometries [5,10] across a multitude of SLS designs [11][12][13][14][15][16] to mitigate generation-recombination (G-R) current and surface-leakage current, while maximizing electrical/optical properties. Among those, detectors with InAs/InAsSb SLSs incorporated in the nBn architecture have received special attention due to high carrier lifetime [16][17][18] and reduced complexity of SLS growth [4]. Since the first demonstration of SLSs for infrared (IR) detectors [12], InAs/Ga(In)Sb SLSs continue to improve [19], while InGaAs/InAsSb SLSs [15,20] have also shown promising results.…”

A Thermoelectrically Cooled nBn Type‐II Superlattices InAs/InAsSb/B‐AlAsSb Mid‐Wave Infrared Detector

“…reported that, in III–V type‐II superlattice (T2SL) detectors, radiative recombination could be far more prevalent than Auger recombination . The SRH G–R contribution should be suppressed by the barrier's incorporation into the detector structure; however, many barrier detectors can be SRH G–R limited, depending on the doping magnitude and the polarity of the absorber and barrier layers, whereas Auger recombination is limited by the detector's designs of the materials characterized by inherently lower Auger recombination rates, e.g., InAs/GaSb and InAs/InAsSb T2SLs . The most important requirement in the design of a barrier detector is the selection of the barrier layer fitted to the active layer in terms of both the valence band offset (VBO) and conduction band offset (CBO).…”