Center for Quantum Devices - Most Downloaded Journal Articles

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18.	High-performance bias-selectable dual-band mid-/long-wavelength infrared photodetectors and focal plane arrays based on InAs/GaSb Type-II superlattices M. Razeghi; A. Haddadi; A.M. Hoang; G. Chen; S. Ramezani-Darvish; P. Bijjam Proc. SPIE 8704, Infrared Technology and Applications XXXIX, 87040S (June 11, 2013)-- June 11, 2013 ...[Visit Journal] We report a bias selectable dual-band mid-wave infrared (MWIR) and long-wave infrared (LWIR) co-located detector with 3 μm active region thickness per channel that is highly selective and can perform under high operating temperatures for the MWIR band. Under back-side illumination, a temperature evolution study of the MWIR detector's electro-optical performance found the 300 K background-limit with 2π field-of-view to be achieved below operating temperatures of 160 K, at which the temperature's 50% cutoff wavelength was 5.2 μm. The measured current reached the system limit of 0.1 pA at 110 K for 30 μm pixel-sized diodes. At 77 K, where the LWIR channel operated with a 50% cutoff wavelength at 11.2 μm, an LWIR selectivity of ∼17% was achieved in the MWIR wave band between 3 and 4.7 μm, making the detector highly selective. [reprint (PDF)]
18.	Materials characterization of n-ZnO/p-GaN:Mg/c-Al(2)O(3) UV LEDs grown by pulsed laser deposition and metal-organic chemical vapor deposition D. Rogers, F.H. Teherani, P. Kung, K. Minder, and M. Razeghi Superlattices and Microstructures-- April 1, 2007 ...[Visit Journal] n-ZnO/p-GaN:Mg hybrid heterojunctions grown on c-Al₂O₃ substrates showed 375 nm room temperature electroluminescence. It was suggested that the high materials and interface quality obtained using pulsed laser deposition for the n-ZnO growth and metal–organic chemical vapor deposition for the p-GaN:Mg were key factors enabling the injection of holes and the radiative near band edge recombination in the ZnO. In this paper we present the materials characterization of this structure using x-ray diffraction, scanning electron microscopy and atomic force microscopy. [reprint (PDF)]
18.	High power photonic crystal distributed feedback quantum cascade lasers emitting at 4.5 micron B. Gokden, S. Slivken and M. Razeghi SPIE Proceedings, San Francisco, CA (January 22-28, 2010), Vol. 7608, p. 760806-1-- January 22, 2010 ...[Visit Journal] Quantum cascade lasers possess very small linewidth enhancement factor, which makes them very prominent candidates for realization of high power, nearly diffraction limited and single mode photonic crystal distributed feedback broad area lasers in the mid-infrared frequencies. In this paper, we present room temperature operation of a two dimensional photonic crystal distributed feedback quantum cascade laser emitting at 4.5 µm. peak power up to ~0.9 W per facet is obtained from a 2 mm long laser with 100 µm cavity width at room temperature. The observed spectrum is single mode with a very narrow linewidth. Far-field profile has nearly diffraction limited single lobe with full width at half maximum of 3.5 degree normal to the facet. The mode selection and power output relationships are experimentally established with respect to different cavity lengths for photonic crystal distributed feedback quantum cascade lasers. [reprint (PDF)]
18.	Room temperature terahertz semiconductor frequency comb Quanyong Lu, Feihu Wang, Donghai Wu, Steven Slivken & Manijeh Razeghi Nature Communications 10, 2403-- June 3, 2019 ...[Visit Journal] A terahertz (THz) frequency comb capable of high-resolution measurement will significantly advance THz technology application in spectroscopy, metrology and sensing. The recently developed cryogenic-cooled THz quantum cascade laser (QCL) comb has exhibited great potentials with high power and broadband spectrum. Here, we report a room temperature THz harmonic frequency comb in 2.2 to 3.3 THz based on difference-frequency generation from a mid-IR QCL. The THz comb is intracavity generated via down-converting a mid-IR comb with an integrated mid-IR single mode based on distributed-feedback grating without using external optical elements. The grating Bragg wavelength is largely detuned from the gain peak to suppress the grating dispersion and support the comb operation in the high gain spectral range. Multiheterodyne spectroscopy with multiple equally spaced lines by beating it with a reference Fabry-Pérot comb confirms the THz comb operation. This type of THz comb will find applications to room temperature chip-based THz spectroscopy. [reprint (PDF)]
18.	Thermal stability of GaN thin films grown on (0001) Al₂O₃, (0112) Al₂O₃ and (0001)Si 6H-SiC substrates C.J. Sun, P. Kung, A. Saxler, H. Ohsato, E. Bigan, M. Razeghi, and D.K. Gaskill Journal of Applied Physics 76 (1)-- July 1, 1994 ...[Visit Journal] Single crystals of GaN were grown on (0001), (0112) Al₂O₃ and (0001)Si 6H‐SiC substrates using an atmospheric pressure metalorganic chemical‐vapor‐deposition reactor. The relationship has been studied between the thermal stability of the GaN films and the substrate’s surface polarity. It appeared that the N‐terminated (0001) GaN surface grown on (0001)Si 6H‐SiC has the most stable surface, followed by the nonpolar (1120) GaN surface grown on (0112) Al₂O₃, while the Ga‐terminated (0001) GaN surface grown on (0001) Al₂O₃ has the least stable surface. This is explained with the difference in the atomic configuration of each of these surfaces which induces a difference in their thermal decomposition. [reprint (PDF)]
18.	High-performance short-wavelength infrared photodetectors based on type-II InAs/InAs_1-xSb_x/AlAs_1-xSb_x superlattices M. Razeghi, A. Haddadi, X. V. Suo, S. Adhikary, P. Dianat, R. Chevallier, A. M. Hoang, A. Dehzangi Proc. SPIE 9819, Infrared Technology and Applications XLII, 98190A -- May 20, 2016 ...[Visit Journal] We present a high-performance short-wavelength infrared n-i-p photodiode, whose structure is based on type-II superlattices with InAs/InAs_1-xSb_x/AlAs_1-xSb_x on GaSb substrate. At room temperature (300K) with front-side illumination, the device shows the peak responsivity of 0.47 A/W at 1.6mm, corresponding to 37% quantum efficiency at zero bias. At 300K, the device has a 50% cut-off wavelength of ~1.8mm. For −50mV applied bias at 300 K the photodetector has dark current density of 9.6x10^-5 A/cm² and RxA of 285 Ω•cm², and it revealed a detectivity of 6.45x10¹⁰ cm•Hz^½/W. Dark current density reached to 1.3x10^-8 A/cm² at 200 K, with 36% quantum efficiency which leads to the detectivity value of 5.66x10¹² cm•Hz^½/W. [reprint (PDF)]
18.	High-brightness LWIR quantum cascade lasers F. Wang, S. Slivken, and M. Razeghi F. Wang, S. Slivken, and M. Razeghi, High-brightness LWIR quantum cascade lasers, Optics Letters, vol. 46, No. 20, 5193 ...[Visit Journal] Long-wave infrared (LWIR, lambda~8-12 um) quantum cascade lasers (QCLs) are drawing increasing interest, as they provide the possibility of long-distance transmission of light through the atmosphere owing to the reduced water absorption. However, their development has been lagging behind the shorter wavelength QCLs due to much bigger technological challenges. In this Letter, through band structure engineering based on a highly localized diagonal laser transition strategy and out-coupler design using an electrically isolated taper structure, we demonstrate high beam quality single-mode LWIR QCLs with high-brightness (2.0 MW cm^-2 sr^-1 for lambda~10 um, 2.2 MW cm^-2 sr^-1 for lambda~9 um, 5.0 MW cm^-2 sr^-1 for lambda~8 um) light extraction from a single facet in continuous-wave operation at 15 ^oC. These results mark an important milestone in exploring the lighting capability of inter-sub-band semiconductor lasers in the LWIR spectral range. [reprint (PDF)]
18.	Polarization-free GaN emitters in the ultraviolet and visible spectra via heterointegration on CMOS-compatible Si (100) C. Bayram, J. Ott, K. T. Shiu, C. W. Cheng, Y. Zhu, J. Kim, D. K. Sadana, M. Razeghi Proc. SPIE 9370, Quantum Sensing and Nanophotonic Devices XII, 93702F -- February 8, 2015 ...[Visit Journal] This work presents a new type of polarization-free GaN emitter. The unique aspect of this work is that the ultraviolet and visible emission originates from the cubic phase GaN and the cubic phase InGaN/GaN multi-quantum-wells, respectively. Conventionally, GaN emitters (e.g. light emitting diodes, laser diodes) are wurtzite phase thus strong polarization fields exist across the structure contributing to the “droop” behavior – a phenomenon defined as “the reduction in emitter efficiency as injection current increases”. The elimination of piezoelectric fields in GaN-based emitters as proposed in this work provide the potential for achieving a 100% internal efficiency and might lead to droopfree light emitting diodes. In addition, this work demonstrates co-integration of GaN emitters on cheap and scalable CMOS-compatible Si (100) substrate, which yields possibility of realizing a GaN laser diode uniquely – via forming mirrors along the naturally occurring cubic phase GaN-Si(100) cleavage planes. [reprint (PDF)]
18.	Substrate emission quantum cascade ring lasers with room temperature continuous wave operation Y. Bai, S. Tsao, N. Bandyopadhyay, S. Slivken, Q.Y. Lu, and M. Razeghi SPIE Proceedings, Vol. 8268, p. 82680N-- January 22, 2012 ...[Visit Journal] We demonstrate room temperature, continuous wave operation of quantum cascade ring lasers around 5 μm with single mode operation up to 0.51 W output power. Single mode operation persists up to 0.4 W. Light is coupled out of the ring cavity through the substrate with a second order distributed feedback grating. The substrate emission scheme allows for epilayer-down bonding, which leads to room temperature continuous wave operation. The far field analysis indicates that the device operates in a high order mode. [reprint (PDF)]
18.	InSb Infrared Photodetectors on Si Substrates Grown by Molecular Beam Epitaxy E. Michel, J. Xu, J.D. Kim, I. Ferguson, and M. Razeghi IEEE Photonics Technology Letters 8 (5) pp. 673-- May 1, 1996 ...[Visit Journal] The InSb infrared photodetectors grown heteroepitaxially on Si substrates by molecular beam epitaxy (MBE) are reported. Excellent InSb material quality is obtained on 3-in Si substrates (with a GaAs predeposition) as confirmed by structural, optical, and electrical analysis. InSb infrared photodetectors on Si substrates that can operate from 77 K to room temperature have been demonstrated. The peak voltage-responsitivity at 4 μm is about 1.0×10³ V/W and the corresponding Johnson-noise-limited detectivity is calculated to be 2.8×10¹⁰ cm·Hz^½/W. This is the first important stage in developing InSb detector arrays or monolithic focal plane arrays (FPAs) on silicon. The development of this technology could provide a challenge to traditional hybrid FPA's in the future. [reprint (PDF)]
17.	Broadband monolithically-tunable quantum cascade lasers Wenjia Zhou, Ryan McClintock, Donghai Wu, Steven Slivken, Manijeh Razeghi Proc. SPIE 10540, Quantum Sensing and Nano Electronics and Photonics XV, 105400A-- January 26, 2018 ...[Visit Journal] Mid-infrared lasers, emitting in the spectral region of 3-12 μm that contain 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, which is critical for spectroscopy applications, is still largely relying on incorporating external gratings, which have stability issues. Here, we demonstrate the development a monolithic, widely 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 with a beam combiner. A compact tunable laser system was built to drive the individual lasers within the array and coordinate the driving of the laser array to produce desired wavelength. A broadband spectral measurement (520cm^-1) of methane shows excellent agreement with Fourier transform infrared spectrometer measurement. Further optimizations have led to high performance monolithic tunable QCLs with up to 65 mW output while delivering fundamental mode outputs. [reprint (PDF)]
17.	High Power 280 nm AlGaN Light Emitting Diodes Based on an Asymmetric Single Quantum Well K. Mayes, A. Yasan, R. McClintock, D. Shiell, S.R. Darvish, P. Kung, and M. Razeghi Applied Physics Letters, 84 (7)-- February 16, 2004 ...[Visit Journal] We demonstrate high-power AlGaN-based ultraviolet light-emitting diodes grown on sapphire with an emission wavelength of 280 nm using an asymmetric single-quantum-well active layer configuration on top of a high-quality AlGaN/AlN template layer. An output power of 1.8 mW at a pulsed current of 400 mA was achieved for a single 300 µm×300 µm diode. This device reached a high peak external quantum efficiency of 0.24% at 40 mA. An array of four diodes produced 6.5 mW at 880 mA of pulsed current. [reprint (PDF)]
17.	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)]
17.	Comparison of PLD-Grown p-NiO/n-Ga2O3 Heterojunctions on Bulk Single Crystal β-Ga2O3 and r-plane Sapphire Substrates D. J. Rogers , V. E. Sandana, F. Hosseini Teherani and M. Razeghi Proc. of SPIE Vol. 12895, Quantum Sensing and Nano Electronics and Photonics XX, 128870J (28 January - 1 February 2024 San Francisco)doi: 10.1117/12.3012511 ...[Visit Journal] p-NiO/n-Ga2O3 heterostructures were formed on single crystal (-201) β (monoclinic) Ga2O3 and r-sapphire substrates by Pulsed Laser Deposition. Ring mesa layer stacks were created using a shadow mask during growth. X-Ray diffraction studies were consistent with the formation of (111) oriented fcc NiO on the bulk Ga2O3 and randomly oriented fcc NiO on (102) oriented β-Ga2O3 /r-sapphire. RT optical transmission studies revealed bandgap energy values of ~3.65 eV and ~5.28 eV for the NiO and Ga2O3 on r-sapphire. p-n junction devices were formed by depositing gold contacts on the layer stacks using shadow masks in a thermal evaporator. Both heterojunctions showed rectifying I/V characteristics. On bulk Ga2O, the junction showed a current density over 16mA/cm2 at +20V forward bias and a reverse bias leakage current over 3 orders of magnitude lower at -20V (1 pA). On Ga2O3/r-sapphire the forward bias current density at +15V was about an order of magnitude lower than for the p-NiO/bulk n-Ga2O3 heterojunction while the reverse bias leakage current at -15V (~ 20 pA) was an order of magnitude higher. Hence the NiO/bulk Ga2O3 junction was more rectifying. Upon illumination with a Xenon lamp a distinct increase in current was observed for the IV curves in both devices (four orders of magnitude for -15V reverse bias in the case of the p-NiO/bulk n-Ga2O3 heterojunction). The p-NiO/n-Ga2O3/rsapphire junction gave a spectral responsivity with a FWHM value of 80nm and two distinct response peaks (with maxima at 230 and 270nm) which were attributed to carriers being photogenerated in the Ga2O3 underlayer. For both devices time response studies showed a 10%/90% rise and fall of the photo generated current upon shutter open and closing which was relatively abrupt (millisecond range), and there was no evidence of significant persistent photoconductivity. [reprint (PDF)]
17.	Kinetics of Quantum States in Quantum Cascade Lasers: Device Design Principles and fabrication M. Razeghi special issue of Microelectronics Journal 30 (10)-- October 1, 1999[reprint (PDF)]
17.	Multi-band SWIR-MWIR-LWIR Type-II superlattice based infrared photodetector Manijeh Razeghi, Arash Dehzangi, Jiakai Li Results in Optics Volume 2, January 2021, 100054 https://doi.org/10.1016/j.rio.2021.100054 ...[Visit Journal] Type-II InAs/GaSb superlattices (T2SLs) has drawn a lot of attention since it was introduced in 1970, especially for infrared detection as a system of multi-interacting quantum wells. In recent years, T2SL material system has experienced incredible improvements in material quality, device structure designs and device fabrication process, which elevated the performances of T2SL-based photo-detectors to a comparable level to the state-of-the-art material systems for infrared detection such as Mercury Cadmium Telluride (MCT). As a pioneer in the field, center for quantum devices (CQD) has been involved in growth, design, characterization, and introduction of T2SL material system for infrared photodetection. In this review paper, we will present the latest development of bias-selectable multi-band infrared photodetectors at the CQD, based on InAs/GaSb/AlSb and InAs/InAs1-xSbx type-II superlattice. [reprint (PDF)]
17.	4.5 mW Operation of AlGaN-based 267 nm Deep-Ultraviolet Light-Emitting Diodes A. Yasan, R. McClintock, K. Mayes, D. Shiell, L. Gautero, S.R. Darvish, P. Kung and M. Razeghi Applied Physics Letters, 83 (23)-- December 8, 2003 ...[Visit Journal] We demonstrate 4.5 mW output power from AlGaN-based single quantum well ultraviolet light-emitting diodes at a very short wavelength of 267 nm in pulsed operation mode. The output power in continuous-wave mode reaches a value of 165 µW at an injected current of 435 mA. The measurements were done on arrays of four devices flip chip bonded to AlN submounts for thermal management. [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.	High power, room temperature, Terahertz sources and frequency comb based on Difference frequency generation at CQD Manijeh Razeghi Proc. of SPIE 12230, 1223006, September 2022 ...[Visit Journal] Quantum cascade laser (QCL) is becoming the leading laser source in the mid-infrared and terahertz range due to its rapid development in power, efficiency, and spectral covering range. Owing to its unique intersubband transition and fast carrier lifetime, QCL possesses strong nonlinear susceptibilities that makes it the ideal platform for a variety of nonlinear optical generations. Among this, terahertz (THz) source based on difference-frequency generation (DFG)and frequency comb based on four wave mixing effect are the most exciting phenomena which could potentially revolutionize spectroscopy in mid-infrared (mid-IR) and THz spectral range. In this paper, we will briefly discuss the recent progress of our research. This includes high power high efficiency QCLs, high power room temperature THz sources based on DFG-QCL, room temperature THz frequency comb, and injection locking of high-power QCL frequency combs. The developed QCLs are great candidates as next generation mid-infrared source for spectroscopy and sensing. [reprint (PDF)]
17.	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)]
17.	Room-temperature continuous-wave operation of quantum-cascade lasers at λ ~ 4 µm J.S. Yu, S.R. Darvish, A. Evans, J. Nguyen, S. Slivken, and M. Razeghi Applied Physics Letters 88 (4)-- January 23, 2006 ...[Visit Journal] High-power cw λ~4 μm quantum-cascade lasers (QCLs) are demonstrated. The effect of different cavity length and laser die bonding is also investigated. For a high-reflectivity-coated 11-μm-wide and 4-mm-long epilayer-down bonded QCL, cw output powers as high as 1.6 W at 80 K and 160 mW at 298 K are obtained, and the cw operation is achieved up to 313 K with 12 mW. [reprint (PDF)]
17.	GaN, GaAlN, and AlN for use in UV Detectors for Astrophysics: An Update P. Kung, A. Saxler, X. Zhang, D. Walker, M. Razeghi, and M. Ulmer SPIE Photonics West '96 Photodetectors: Materials and Devices; Proceedings 2685-- January 27, 1996 ...[Visit Journal] In SPIE Proceeding 2397 we demonstrated that there is a large payoff still to be gained by further improvements in the performance of solar blind UV detectors for astronomical purposes. We suggested that a particularly promising future technology is one based on the ability of investigators to produce high-quality films made of wide bandgap III-IV semiconductors. Here we report on significant progress we have made over the past year to fabricate and test single-pixel devices. The next step will be to measure and improve detective efficiency, measure the solar blindness over a larger dynamic range, and begin developing multiple-pixel designs. [reprint (PDF)]
17.	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)]
17.	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)]
17.	Long-Wavelength InAsSb Photoconductors Operated at Near Room Temperatures (200-300 K) J.D. Kim, D. Wu, J. Wojkowski, J. Piotrowski, J. Xu, and M. Razeghi Applied Physics Letters., 68 (1),-- January 1, 1996 ...[Visit Journal] Long-wavelength InAs_1−xSb_x photoconductors operated without cryogenic cooling are reported. The devices are based on p-InAs_1−xSb_x/p-InSb heterostructures grown on (100) semi-insulating GaAs substrates by low pressure metalorganic chemical vapor deposition (LP‐MOCVD). Photoreponse up to 14 μm has been obtained in a sample with x=0.77 at 300 K, which is in good agreement with the measured infrared absorption spectra. The corresponding effective lifetime of ≊0.14 ns at 300 K has been derived from stationary photoconductivity. The Johnson noise limited detectivity at λ=10.6 μm is estimated to be about 3.27×10⁷ cm· Hz^½/W at 300 K. [reprint (PDF)]

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