Bias-switchable dual-band HgCdTe infrared photodetector

Abstract

The feasibility of an all molecular-beam epitaxially (MBE) grown, bias-switchable, dual-band HgCdTe detector is demonstrated. Detection in the midwavelength infrared (MWIR) band only or the long-wavelength band (LWIR) only is accomplished by the proper selection of detector bias in the ≥±100 mV range. The devices were all grown in situ by the MBE on CdZnTe or GaAs substrates and consisted of three intentionally doped layers in an n–p–n sequence. At 77 K the floating base two terminal devices responded to the ∼4.9–8 μm spectral band with the application of ≥−100 mV to the bottom contact and to the ∼2.1–4.9 μm band with the application of ≥0 mV. Quantum efficiency depended on bias with a maximum of 59% for LWIR and 66% for MWIR wavelengths at −150 mV and ≥0 mV, respectively. The operation of the dual-band detector is discussed. Significant design differences between the heterojunction phototransistor and the dual-band detector are noted.

Developing high-performance III-V superlattice IRFPAs for defense: challenges and solutions

“…Detailed discussions about multiple design options with different layer sequences using non-superlattice materials, as well as the etch depth options and spectral cross talk, can be found in the literature. [34][35][36] Initial experimental results with antimonide superlattice materials were also reported in the literature. [37][38] An existing challenge for superlattice dual-band detector design is to accurately control the multiple layer growth and realize the designed band alignment at either voltage bias polarity to achieve high performance at each band, while minimizing electrical and optical cross talk.…”

Optically addressed near and long-wave infrared multiband photodetectors

“…Peak specific detectivity (D*) of the detector in LWIR mode is measured to be 2 Â 10 9 cm Hz 1/2 /W under 290 K background and 180 field of view, at an optical bias of 0.12 W/cm 2 and an electrical bias of À1 V. The detectivity will improve with grating coupling, the same QWIP design with back-side illumination and top-side etched grating coupling is suitable for FPA imaging with long integration times. 6,24,26 Figure 5 shows the peak responsivity and D* vs. bias voltage for the LWIR mode of operation.…”

“…1,2 Multiband infrared FPA using these principles or using more than two terminals per pixel have been reported. [2][3][4][5][6][7][8][9] Dual-band type-II superlattice infrared photodetectors, 10,11 fourcolor QWIPs, 12 voltage-tunable quantum-dot infrared photodetectors (QDIP), 13 and voltage-switchable NIR/LWIR imaging with QWIPs were also reported. 14 Without band switching, InSb, HgCdTe, QWIP, [15][16][17] and InGaAs (Ref.…”

New material systems for third generation infrared photodetectors

“…A variation on the original back to back concept was implemented using HgCdTe at Rockwell [112] and Santa Barbara Research Center [113]. Following the successful demonstration of multispectral detectors in LPE-grown HgCdTe devices [113], the MBE and MOCVD techniques have been used for the grown of a variety of multispectral detectors at Raytheon [27,[114][115][116][117], BAE Systems [118], Leti [28,30,[119][120][121], Selex and QinetiQ [29,122,123], DRS, [26,124,125] Teledyne and NVESD [126,127].…”