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18.  Recent advances in IR semiconductor laser diodes and future trends
M. Razeghi; Y. Bai; N. Bandyopadhyay; B. Gokden; Q.Y. Lu; S. Slivken
Photonics Society Summer Topical Meeting Series, IEEE [6000041], pp. 55-56 (2011)-- July 18, 2011 ...[Visit Journal]
The wall plug efficiency of the mid-infrared quantum cascade laser in room temperature continuous wave (cw) operation is brought to 21%, with a maximum output power of 5.1 W. Using a surface grating distributed feedback (DFB) approach, we demonstrated 2.4 W single mode output in room temperature cw operation. With a photonic crystal distributed feedback (PCDFB) design, we achieved single mode spectrum and close to diffraction limited far field with a room temperature high peak power of 34 W. [reprint (PDF)]
 
18.  High Performance Quantum Cascade Lasers at λ ~ 6 μm
M. Razeghi, S. Slivken, J. Yu, A. Evans, and J. David
Microelectronics Journal, 34 (5-8)-- May 1, 2003 ...[Visit Journal]
This talk will focus on the recent efforts at the Center for Quantum Devices to deliver a high average power quantum cascade laser source at λ ~6 μm. Strain-balancing is used to reduce leakage for these shorter wavelength quantum cascade lasers. Further, the effect of reducing the doping in the injector is explored relative to the threshold current density and maximum average output power. Lastly, to demonstrate more of the potential of these devices, epilayer down bonding is explored as a technique to significantly enhance device performance. [reprint (PDF)]
 
18.  High performance monolithic, broadly tunable mid-infrared quantum cascade lasers
WENJIA Zhou, DONGHAI Wu, RYAN McCLINTOCK, STEVEN SLIVKEN, AND MANIJEH RAZEGH1
Optica 4(10), p. 1228-- October 10, 2017 ...[Visit Journal]
Mid-infrared lasers, emitting in the spectral region of 3-12 µm that contains strong characteristic vibrational tran­sitions of many important molecules, are highly desirable for spectroscopy sensing applications. High-efficiency quantum cascade lasers have been demonstrated with up to watt-level output power in the mid-infrared region. However, the wide wavelength tuning that is critical for spectroscopy applica­tions still largely relies on incorporating external gratings, which have stability issues. Here, we demonstrate a mono­lithic, broadly tunable quantum cascade laser source emitting between 6.1 and 9.2 µm through an on-chip integration of a sampled grating distributed feedback tunable laser array and a beam combiner. High peak power up to 65 mW has been obtained through a balanced high-gain active region design, efficient waveguide layout, and the development of a broad­band antireflection coating. Nearly fundamental transverse­mode operation is achieved for all emission wavelengths with a pointing stability better than 1.6 mrad (0.1 °). The demon­strated laser source opens new opportunities for mid-infrared spectroscopy. [reprint (PDF)]
 
18.  Low threshold GaInAsP/InP lasers with good temperature dependence grown by low pressure MOVPE
J.-P. Hirtz, M. Razeghi, J.-P. Larivain, S. Hersee, J.-P. Duchemin
Electronics Letters Volume 17, Issue 3 https://doi.org/10.1049/el:19810081-- February 1, 1981 ...[Visit Journal]
Room temperature pulsed operation has been achieved in the 1.2–1.3 μm region for GaInAsP/InP lasers grown by low pressure metalorganic vapour phase epitaxy. Thresholds as low as 1.2 kA/cm2 and threshold temperature dependences of exp T/T0, with T0 up to 80 K, have been obtained. [reprint (PDF)]
 
18.  Optical Coatings by ion-beam sputtering deposition for long-wave infrared quantum cascade lasers
J. Nguyen, J.S. Yu, A. Evans, S. Slivken and M. Razeghi
Applied Physics Letters, 89 (11)-- September 11, 2006 ...[Visit Journal]
The authors report on the development of high-reflection and multilayer antireflection coatings using ion-beam sputtering deposition for long-wave infrared (λ~9.4 μm) quantum cascade lasers. A metallic high-reflection coating structure using Y2O3 and Au is demonstrated to achieve a high reflectance of 96.70%, and the use of a multilayer anti-reflection coating structure using PbTe and ZnO is demonstrated to achieve a very low reflectance of 1.64%. [reprint (PDF)]
 
18.  Type-II superlattice-based extended short-wavelength infrared focal plane array with an AlAsSb/GaSb superlattice etch-stop layer to allow near-visible light detection
Romain Chevallier, Arash Dehzangi, Abbas Haddadi, and Manijeh Razeghi
Optics Letters Vol. 42, Iss. 21, pp. 4299-4302-- October 17, 2017 ...[Visit Journal]
A versatile infrared imager capable of imaging the near-visible to the extended short-wavelength infrared (e-SWIR) is demonstrated using e-SWIR InAs/GaSb/AlSb type-II superlattice-based photodiodes. A bi-layer etch-stop scheme consisting of bulk InAs0.91Sb0.09 and AlAs0.1Sb0.9/GaSb superlattice layers is introduced for substrate removal from the hybridized back-side illuminated photodetectors. The implementation of this new technique on an e-SWIR focal plane array results in a significant enhancement in the external quantum efficiency (QE) in the 1.8–0.8μm spectral region, while maintaining a high QE at wavelengths longer than 1.8μm. Test pixels exhibit 100% cutoff wavelengths of ∼2.1 and ∼2.25μm at 150 and 300K, respectively. They achieve saturated QE values of 56% and 68% at 150 and 300K, respectively, under back-side illumination and without any anti-reflection coating. At 150K, the photodetectors (27μm×27μm area) exhibit a dark current density of 4.7×10−7  A/cm2 under a −50  mV applied bias providing a specific detectivity of 1.77×1012  cm·Hz1/2/W. At 300K, the dark current density reaches 6.6×10−2  A/cm2 under −50 mV bias, providing a specific detectivity of 5.17×109  cm·Hz1/2/W. [reprint (PDF)]
 
18.  Recent progress of quantum cascade laser research from 3 to 12 μm at the Center for Quantum Devices
MANIJEH RAZEGHI,* WENJIA ZHOU,STEVEN SLIVKEN,QUAN-YONG LU,DONGHAI WU, AND RYAN MCCLINTOC
Applied Optics Vol. 56, No. 31 -- October 10, 2017 ...[Visit Journal]
The quantum cascade laser (QCL) is becoming the leading laser source in the mid-infrared (mid-IR) range, which contains two atmospheric transmission windows and many molecular fingerprint absorption features. Since its first demonstration in 1994, the QCL has undergone tremendous development in terms of the output power, wall plug efficiency, wavelength coverage, tunability and beam quality. At the Center for Quantum Devices, we have demonstrated high-power continuous wave operation of QCLs covering a wide wavelength range from 3 to 12 μm, with power output up to 5.1 W at room temperature. Recent research has resulted in power scaling in pulsed mode with up to 203 W output, electrically tunable QCLs based on monolithic sampled grating design, heterogeneous QCLs with a broad spectral gain, broadly tunable on-chip beam-combined QCLs, QCL-based mid-IR frequency combs, and fundamental mode surface emitting quantum cascade ring lasers. The developed QCLs will be the basis for a number of next-generation spectroscopy and sensing systems. [reprint (PDF)]
 
18.  Terahertz emitters at Center for Quantum Devices: recent advances and future trends
Manijeh Razeghi
Proc. SPIE 10177, Infrared Technology and Applications XLIII, 1017705-- August 23, 2018 ...[Visit Journal]
This paper reviews the recent advances and future trends of terahertz (THz) emitters at CQD/NU, highlights the high-performance THz sources based on intracavity nonlinear frequency generation in mid-infrared quantum cascade lasers. Significant performance improvements of our THz sources in the power, wall plug efficiency are achieved by systematic optimizing the device's active region, waveguide, and chip bonding strategy. High THz power up to 1.9 mW and 0.014 mW for pulsed mode and continuous wave operations at room temperature are demonstrated, respectively. Even higher power and efficiency are envisioned based on enhancements in outcoupling efficiency and mid-IR performance. Our compact THz device with high power and wide tuning range is highly suitable for the imaging, sensing, spectroscopy, medical diagnosis, and many other applications. [reprint (PDF)]
 
18.  Avalanche multiplication in AlGaN based solar-blind photodetectors
R. McClintock, A. Yasan, K. Minder, P. Kung, and M. Razeghi
Applied Physics Letters, 87 (24)-- December 12, 2005 ...[Visit Journal]
Avalanche multiplication has been observed in solar-blind AlGaN-based p-i-n photodiodes. Upon ultraviolet illumination, the optical gain shows a soft breakdown starting at relatively low electric fields, eventually saturating without showing a Geiger mode breakdown. The devices achieve a maximum optical gain of 700 at a reverse bias of 60 V. By modeling the device, it is found that this corresponds to an electric-field strength of 1.7 MV/cm. [reprint (PDF)]
 
18.  Room temperature continuous wave operation of λ ~ 3-3.2 μm quantum cascade lasers
N. Bandyopadhyay, Y. Bai, S. Tsao, S. Nida, S. Slivken and M. Razeghi
Applied Physics Letters, Vol. 101, No. 24, p. 241110-1-- December 10, 2012 ...[Visit Journal]
We demonstrate quantum cascade lasers emitting at wavelengths of 3–3.2 μm in the InP-based material system. The laser core consists of GaInAs/AlInAs using strain balancing technique. In room temperature pulsed mode operation, threshold current densities of 1.66 kA∕cm² and 1.97 kA∕cm², and characteristic temperatures (T0) of 108 K and 102 K, are obtained for the devices emitting at 3.2 μm and 3 μm, respectively. Room temperature continuous wave operation is achieved at both wavelengths. [reprint (PDF)]
 
18.  Resonant cavity enhanced heterojunction phototransistors based on type-II superlattices
Jiakai Li, Arash Dehzangi, Donghai Wu, Ryan McClintock, Manijeh Razeghi
Infrared Physics & Technology Available online 27 October 2020, 103552 https://doi.org/10.1016/j.infrared.2020.103552-- October 27, 2020 ...[Visit Journal]
Resonant cavity enhanced heterojunction phototransistor based on InAs/GaSb/AlSb type-II superlattice grown by molecular beam epitaxy has been demonstrated. The resonant wavelength was designed to be at near 1.9 μm wavelength range at room temperature. An eleven-pair lattice matched GaSb-AlAsSb quarter-wavelength Bragg reflector was used in the RCE-HPT to enhance the photoresponse. The device showed the wavelength selectivity and a cavity enhancement of the responsivity at 1.9 μm at room temperature. [reprint (PDF)]
 
18.  Extended short-wavelength infrared nBn photodetectors based on type-II InAs/AlSb/GaSb superlattices with an AlAsSb/GaSb superlattice barrier
A. Haddadi, R. Chevallier, A. Dehzangi, and M. Razeghi
Applied Physics Letters 110, 101104-- March 8, 2017 ...[Visit Journal]
Extended short-wavelength infrared nBn photodetectors based on type-II InAs/AlSb/GaSb superlattices on GaSb substrate have been demonstrated. An AlAsSb/GaSb H-structure superlattice design was used as the large-bandgap electron-barrier in these photodetectors. The photodetector is designed to have a 100% cut-off wavelength of ∼2.8 μm at 300 K. The photodetector exhibited a room-temperature (300 K) peak responsivity of 0.65 A/W at 1.9 μm, corresponding to a quantum efficiency of 41% at zero bias under front-side illumination, without any anti-reflection coating. With an R × A of 78 Ω·cm² and a dark current density of 8 × 10−3 A/cm² under −400 mV applied bias at 300 K, the nBn photodetector exhibited a specific detectivity of 1.51 × 1010 Jones. At 150 K, the photodetector exhibited a dark current density of 9.5 × 10−9 A/cm² and a quantum efficiency of 50%, resulting in a detectivity of 1.12 × 1013 Jones. [reprint (PDF)]
 
18.  Growth and characterization of InAs/GaSb Type-II superlattices for long-wavelength infrared detectors
H. Mohseni, E. Michel, M. Razeghi, W. Mitchel, and G. Brown
SPIE Conference, San Jose, CA, -- January 28, 1998 ...[Visit Journal]
We report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi- insulating GaAs substrate for long wavelength IR detectors. Photoconductive detectors fabricated from the superlattices showed 80% cut-off at 11.6 μm and peak responsivity of 6.5 V/W with Johnson noise limited detectivity of 2.36 x 109 cm·Hz½/W at 10.7 μm at 78 K. The responsivity decreases at higher temperatures with a T-2 behavior rather than exponential decay, and at room temperature the responsivity is about 660 mV/W at 11 μm. Lower Auger recombination rate in this system provides comparable detectivity to the best HgCdTe detectors at 300K. Higher uniformity over large areas, simpler growth and the possibility of having read-out circuits in the same GaAs chip are the advantages of this system over HgCdTe detectors for near room temperature operation. [reprint (PDF)]
 
18.  Continuous operation of a monolithic semiconductor terahertz source at room temperature
Q. Y. Lu, N. Bandyopadhyay, S. Slivken, Y. Bai, and M. Razeghi
Appl. Phys. Lett. 104, 221105 (2014)-- June 3, 2014 ...[Visit Journal]
We demonstrate room temperature continuous wave THz sources based on intracavity difference-frequency generation from mid-infrared quantum cascade lasers. Buried ridge, buried composite distributed-feedback waveguide with Čerenkov phase-matching scheme is used to reduce the waveguide loss and enhance the heat dissipation for continuous wave operation. Continuous emission at 3.6 THz with a side-mode suppression ratio of 20 dB and output power up to 3 μW are achieved, respectively. THz peak power is further scaled up to 1.4 mW in pulsed mode by increasing the mid-infrared power through increasing the active region doping and device area. [reprint (PDF)]
 
17.  First GaInAsP‐InP double‐heterostructure laser emitting at 1.27 μm on a silicon substrate
M. Razeghi; M. Defour; F. Omnes; Ph. Maurel; J. Chazelas; F. Brillouet
Appl. Phys. Lett. 53, 725–727 (1988)-- June 21, 1988 ...[Visit Journal]
We report the first successful room-temperature GalnAsP-InP double-heterostructure laser emitting at 1.27 pm, grown by low-pressure metalorganic chemical vapor deposition on a Si substrate. A pulsed threshold current density of 10 kAlcm2 at room temperature with an external quantum efficiency of 10% per facet and an output power of20 mW (for an oxidedefined stripe geometry with 12 pm stripe width and 250 pm cavity length) has been measured. The first aging test in pulse operation shows an increase of threshold current of only 7% for a cumulative time of 80 s at room temperature. [reprint (PDF)]
 
17.  Growth and characterization of InAs/GaSb photoconductors for long wavelength infrared range
H. Mohseni, E. Michel, J. Sandven, M. Razeghi, W. Mitchel, and G. Brown
Applied Physics Letters 71 (10)-- September 8, 1997 ...[Visit Journal]
In this letter we report the molecular beam epitaxial growth and characterization of InAs/GaSb superlattices grown on semi-insulating GaAs substrates for long wavelength infrared detectors. Photoconductive detectors fabricated from the superlattices showed photoresponse up to 12 µm and peak responsivity of 5.5 V/W with Johnson noise limited detectivity of 1.33 × 109 cm·Hz½/W at 10.3 µm at 78 K. [reprint (PDF)]
 
17.  High power, high wall-plug efficiency, high reliability, continuous-wave operation quantum cascade lasers at Center for Quantum Devices
Razeghi, Manijeh
SPIE Proceedings Volume 11296, Optical, Opto-Atomic, and Entanglement-Enhanced Precision Metrology II; 112961C-- February 25, 2020 ...[Visit Journal]
Since the demonstration of the first quantum cascade laser (QCL) in 1997, QCLs have undergone considerable developments in output power, wall plug efficiency (WPE), beam quality, wavelength coverage and tunability. Among them, many world-class breakthroughs were achieved at the Center for Quantum Device at Northwestern University. In this paper, we will discuss the recent progress of our research and present the main contributions of the Center for Quantum Devices to the QCL family on high power, high wall-plug efficiency (WPE), continuous-wave (CW) and room temperature operation lasers. [reprint (PDF)]
 
17.  Status of III-V semiconductor thin films and their applications to future OEICs
Manijeh Razeghi
Proc. SPIE 10267, Integrated Optics and Optoelectronics, 102670T -- June 26, 2017 ...[Visit Journal]
In the last decade, semiconductor technology has been advanced to a great extent in terms of electronic and photonic discrete devices. One of the main reasons for such a progress, is the result of advancement in the epitaxial growth techniques such as molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD), where device quality films can be grown with great control over composition, uniformity and thickness. MOCVD has proven to be one of the best growth methods for many IH-V semiconductor thin films 1. Its flexibility and potential to yield a broad range of growth rates resulted in the layers featuring the thicknesses from tens of microns down to several nanometers. Planar structures containing quantum wells with atomically flat interfaces, superlattices, strained or graded-index layers were successfully grown by MOCVD. Furthermore, MOCVD proved its efficiency in producing a laser devices by overgrowth and epitaxy on patterned substrates. The importance of MOCVD is strongly enhanced by the possibility of large-scale production by simultaneous growth on several substrates in one process. Several III-V semiconductor films with bandgaps ranging from infrared to ultraviolet (15 to 0.2 μm) have been successfully grown by MOCVD. [reprint (PDF)]
 
17.  Monolithic Integration of GaInAs/InP Quantum Well Infrared Photodetectors on Si Substrate
M. Erdtmann and M. Razeghi
SPIE Conference, San Jose, CA, -- January 22, 2001 ...[Visit Journal]
Using low-pressure metalorganic chemical vapor deposition, we have grown GaInAs/InP QWIP structures on GaAs-coated Si substrate. First, the procedure to optimize the epitaxy of the InP buffer layer on Si substrate is given. Excellent crystallinity and a mirror-like surface morphology were obtained by using both a two-step growth process at the beginning of the InP buffer layer growth and several series of thermal cycle annealing throughout the InP buffer layer growth. Second, results of fabricated GaInAs/InP QWIPs on Si substrate are presented. At a temperature of 80 K, the peak response wavelength occurs at 7.4 μm. The responsivities of QWIPs on both Si and InP substrates with identical structures are equal up to biases of 1.5 V. At a bias of 3 V, the responsivity of the QWIPs on Si substrate is 1.0 A/W. [reprint (PDF)]
 
17.  High performance antimony based type-II superlattice photodiodes on GaAs substrates
B.M. Nguyen, D. Hoffman, E.K. Huang, P.Y. Delaunay, and M. Razeghi
SPIE Porceedings, Vol. 7298, Orlando, FL 2009, p. 72981T-- April 13, 2009 ...[Visit Journal]
In recent years, Type-II InAs/GaSb superlattices grown on GaSb substrate have achieved significant advances in both structural design and material growth, making Type-II superlattice infrared detector a rival competitor to the state-of-the-art MCT technology. However, the limited size and strong infrared absorption of GaSb substrates prevent large format type-II superlattice infrared imagers from being realized. In this work, we demonstrate type-II superlattices grown on GaAs substrates, which is a significant step toward third generation infrared imaging at low cost. The device performances of Type-II superalttice photodetectors grown on these two substrates are compared. [reprint (PDF)]
 
17.  Photoluminescence characteristics of polar and nonpolar AlGaN/GaN superlattices
Z. Vashaei, C. Bayram, P. Lavenus, and M. Razeghi
Applied Physics Letters, Vol. 97, No. 12, p. 121918-1-- September 20, 2010 ...[Visit Journal]
High quality Al0.2Ga0.8N/GaN superlattices (SLs) with various (GaN) well widths (1.6 to 6.4 nm) have been grown on polar c-plane and nonpolar m-plane freestanding GaN substrates by metal-organic chemical vapor deposition. Atomic force microscopy, high resolution x-ray diffraction, and photoluminescence (PL) studies of SLs have been carried out to determine and correlate effects of well width and polarization field on the room-temperature PL characteristics. A theoretical model was applied to explain PL energy-dependency on well width and crystalline orientation taking into account internal electric field for polar substrate. Absence of induced-internal electric field in nonpolar SLs was confirmed by stable PL peak energy and stronger PL intensity as a function of excitation power density than polar ones. [reprint (PDF)]
 
17.  Development of material quality and structural design for high performance type-II InAs/GaSb superlattice photodiodes and focal plane arrays
M. Razeghi, B.M. Nguyen, D. Hoffman, P.Y. Delaunay, E.K. Huang, M.Z. Tidrow and V. Nathan
SPIE Porceedings, Vol. 7082, San Diego, CA 2008, p. 708204-- August 11, 2008 ...[Visit Journal]
Recent progress made in the structure design, growth and processing of Type-II InAs/GaSb superlattice photo-detectors lifted both the quantum efficiency and the R0A product of the detectors. Type-II superlattice demonstrated its ability to perform imaging in the Mid-Wave Infrared (MWIR)and Long-Wave Infrared (LWIR) ranges, becoming a potential competitor for technologies such as Quantum Well Infrared Photo-detectors (QWIP) and Mercury Cadmium Telluride (MCT). Using an empirical tight-binding model, we developed superlattices designs that were nearly lattice-matched to the GaSb substrates and presented cutoff wavelengths of 5 and 11 μm. We demonstrated high quality material growth with X-ray FWHM below 30 arcsec and an AFM rms roughness of 1.5 Å over an area of 20x20 μm2. The detectors with a 5 μm cutoff, capable of operating at room temperature, showed a R0A of 1.25 106 Ω.cm2 at 77K, and a quantum efficiency of 32%. In the long wavelength infrared, we demonstrated high quantum efficiencies above 50% with high R0A products of 12 Ω.cm2 by increasing the thickness of the active region. Using the novel M-structure superlattice design, more than one order of magnitude improvement has been observed for electrical performance of the devices. Focal plane arrays in the middle and long infrared range, hybridized to an Indigo read out integrated circuit, exhibited high quality imaging. [reprint (PDF)]
 
17.  High-performance bias-selectable dual-band Short-/Mid-wavelength infrared photodetectors and focal plane arrays based on InAs/GaSb/AlSb Type-II superlattices
M. Razeghi; A.M. Hoang; A. Haddadi; G. Chen; S. Ramezani-Darvish; P. Bijjam; P. Wijewarnasuriy; E. Decuir
Proc. SPIE 8704, Infrared Technology and Applications XXXIX, 87041W (June 18, 2013)-- June 18, 2013 ...[Visit Journal]
We report a bias selectable dual-band Type-II superlattice-based short-wave infrared (SWIR) and mid-wave infrared (MWIR) co-located photodetector capable of active and passive imaging. A new double-layer etch-stop scheme is introduced for back-side-illuminated photodetectors, which enhanced the external quantum efficiency both in the SWIR and MWIR spectral regions. Temperature-dependent dark current measurements of pixel-sized 27 μm detectors found the dark current density to be ∼1×10-5 A/cm2 for the ∼4.2 μm cut-off MWIR channel at 140 K. This corresponded to a reasonable imager noise equivalent difference in temperature of ∼49 mK using F/2.3 optics and a 10 ms integration time (tint), which lowered to ∼13 mK at 110 K using and integration time of 30 ms, illustrating the potential for high-temperature operation. The SWIR channel was found to be limited by readout noise below 150 K. An excellent imagery from the dual-band imager exemplifying pixel coincidence is shown. [reprint (PDF)]
 
17.  Comparison of ultraviolet light-emitting diodes with peak emission at 340 nm grown on GaN substrate and sapphire
A. Yasan, R. McClintock, K. Mayes, S.R. Darvish, H. Zhang, P. Kung, M. Razeghi, S.K. Lee and J.Y. Han
Applied Physics Letters, 81 (12)-- September 16, 2002 ...[Visit Journal]
Based on AlInGaN/AlInGaN multiquantum wells, we compare properties of ultraviolet light-emitting diodes (LED) with peak emission at 340 nm grown on free-standing hydride vapor phase epitaxially grown GaN substrate and on sapphire. For the LED grown on GaN substrate, a differential resistance as low as 13 Ω and an output power of more than one order of magnitude higher than that of the same structure grown on sapphire are achieved. Due to higher thermal conductivity of GaN, output power of the LEDs saturates at higher injection currents compared to the devices grown on sapphire. [reprint (PDF)]
 
17.  Type-II InAs/GaSb superlattice photovoltaic detectors with cutoff wavelength approaching 32 μm
Y. Wei, A. Gin, M. Razeghi and G.J. Brown
Applied Physics Letters, 81 (19)-- November 4, 2002 ...[Visit Journal]
We report the most recent advance in the area of type-II InAs/GaSb superlattice photovoltaic detectors that have cutoff wavelengths beyond 25 μm, with some at nearly 32 μm. The photodiodes with a heterosuperlattice junction showed Johnson noise limited peak detectivity of 1.05 x 1010 cm Hz½/W at 15 μm under zero bias, and peak responsivity of 3 A/W under -40 mV reverse bias at 34 K illuminated by ~300 K background with a 2π field-of-view. The maximum operating temperature of these detectors ranges from 50 to 65 K. No detectable change in the blackbody response has been observed after 5-6 thermal cyclings, with temperature varying between 15 and 296 K in vacuum. [reprint (PDF)]
 

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