Center for Quantum Devices - Most Downloaded Journal Articles

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2.	Responsivity and Noise Performance of InGaAs/InP Quantum Well Infrared Photodetectors C. Jelen, S. Slivken, T. David, G. Brown, and M. Razeghi SPIE Conference, San Jose, CA, -- January 28, 1998 ...[Visit Journal] Dark current nose measurements were carried out between 10 and 104 Hz at T = 80K on two InGaAs/InP quantum well IR photo detectors (QWIPs) designed for 8 μm IR detection. Using the measured noise data, we have calculated the thermal generation rate, bias-dependent gain, electron trapping probability, and electron diffusion length. The calculated thermal generation rate is similar to AlGaAs/GaAs QWIPs with similar peak wavelengths, but the gain is 50X larger, indicating improved transport and carrier lifetime are obtained in the binary InP barriers. As a result, a large responsivity of 7.5 A/W at 5V bias and detectivity of 5 X 10¹¹ cm·Hz^½/W at 1.2 V bias were measured for the InGaAs/InP QWIPs at T = 80K. [reprint (PDF)]
2.	Quantum-dot infrared photodetectors and focal plane arrays M. Razeghi, H. Lim, S. Tsao, M. Taguchi, W. Zhang, and A.A. Quivy SPIE Infrared Technology and Applications Conference, April 17-21, 2006, Orlando, FL Proceedings – Infrared Technology and Applications XXXII, Vol. 6206, p. 62060I-1-- April 21, 2006 ...[Visit Journal] We report our recent results about mid-wavelength infrared quantum-dot infrared photodetectors (QDIPs) grown by low-pressure metalorganic chemical vapor deposition. A very high responsivity and a very low dark current were obtained. A high peak detectivity of the order of 3×10¹² Jones was achieved at 77 K. The temperature dependent device performance was also investigated. The improved temperature insensitivity compared to QWIPs was attributed to the properties of quantum dots. The device showed a background limited performance temperature of 220 K with a 45° field of view and 300K background. [reprint (PDF)]
2.	Aluminum-free Quantum Well Intersubband Photodetectors with p-type GaAs Wells and lattice-matched ternary and quaternary barriers J. Hoff, E. Bigan, G.J. Brown, and M. Razeghi Optoelectronic Integrated Circuit Materials, Physics and Devices, SPIE Conference, San Jose, CA; Proceedings, Vol. 2397-- February 6, 1995 ...[Visit Journal] Acceptor doped Quantum Well Intersubband Photodetectors with GaAs wells and lattice matched barriers of both ternary (In_0.49Ga_0.51P) and quaternary (In_0.62Ga_0.38As_0.22P_0.78) materials have been grown on semi-insulating GaAs substrates by Low Pressure Metal Organic Chemical Vapor Deposition. Mesa devices were fabricated and subjected to a series of tests to illuminate experimentally some of the detection capabilities of the lattice matched quaternary InxGa1-xAsyP1-y system with (0 ≤ x ≤ 0.52) and (0 ≤ y ≤ 1). The observed photoresponse cut-off wavelengths are in good agreement with the activation energies observed in the temperature dependence of the dark currents. Kronig-Penney calculations were used to model the intersubband transition energies. [reprint (PDF)]
2.	High-power, room-temperature and continuous-wave operation of distributed-feedback quantum-cascade lasers at λ = 4.8 µm J.S. Yu, S. Slivken, S.R. Darvish, A. Evans, B. Gokden and M. Razeghi Applied Physics Letters, 87 (4)-- July 25, 2005 ...[Visit Journal] The authors present high-power continuous-wave (cw) operation of distributed-feedback quantum-cascade lasers. Continuous-wave output powers of 56 mW at 25 °C and 15 mW at 40 °C are obtained. Single-mode emission near 7.8 µm with a side-mode suppression ratio of >=30 dB and a tuning range of 2.83 cm⁻¹ was obtained between 15 and 40 °C. The device exhibits no beam steering with a full width at half maximum of 27.4° at 25 °C in cw mode. [reprint (PDF)]
2.	Electrical Characterization of Al_xGa_1-xN for UV Photodetector Applications A. Saxler, M. Ahoujja, W.C. Mitchel, P. Kung, D. Walker, and M. Razeghi SPIE Conference, San Jose, CA, -- January 27, 1999 ...[Visit Journal] Ultraviolet photodetectors have many military and commercial applications. However, for many of these applications, the photodetectors must be solar blind. This means that the photodetectors must have a cutoff wavelength of less than about 270 nm. Semiconductor based devices would then need energy gaps of over 4.6 eV. In the Al_xGa_1-xN system, the aluminum mole fraction, x, required is over 40%. As the energy gap is increased, doping becomes much more difficult, especially p-type doping. This report is a study of the electrical properties of Al_xGa_1-xN to enable better control of the doping. Magnesium doped p-type Al_xGa_1-xN has been studied using high-temperature Hall effect measurements. The acceptor ionization energy has been found to increase substantially with the aluminum content. Short-period superlattices consisting of alternating layers of GaN:Mg and AlGaN:Mg were also grown by low-pressure organometallic vapor phase epitaxy. The electrical properties of these superlattices were measured as a function of temperature and compared to conventional AlGaN:Mg layers. It is shown that the optical absorption edge can be shifted to shorter wavelengths while lowering the acceptor ionization energy by using short- period superlattice structures instead of bulk-like AlGaN:Mg. Silicon doped n-type films have also been studied. [reprint (PDF)]
2.	Relaxation kinetics in quantum cascade laser S. Slivken, V. Litvinov, M. Razeghi, and J.R. Meyer Journal of Applied Physics 85 (2)-- January 15, 1999 ...[Visit Journal] Relaxation kinetics in a quantum cascade intersubband laser are investigated. Distribution functions and gain spectra of a three-subband double-quantum-well active region are obtained as a function of temperature and injection current. The potentially important role of the nonequilibrium phonons at lasing threshold is shown and discussed in details. It is shown that the threshold current is strongly dependent of the power dissipated in the active region in steady state. The numerical calculations for an 8.5 μm laser illustrate the general issues of relaxation kinetics in quantum cascade lasers. Temperature dependence of the threshold current is obtained in a good agreement with the experiments. [reprint (PDF)]
2.	Passivation of Type-II InAs/GaSb Superlattice Photodiodes A. Gin, Y. Wei, J. Bae, A. Hood, J. Nah, and M. Razeghi International Conference on Metallurgical Coatings and Thin Films (ICMCTF), San Diego, CA; Thin Solid Films 447-448-- January 30, 2004 ...[Visit Journal] Recently, excellent infrared detectors have been demonstrated using Type-II InAs/GaSb superlattice materials sensitive at wavelengths from 3 μm to greater than 32 μm. These results indicate that Type-II superlattice devices may challenge the preponderance of HgCdTe and other state-of-the-art infrared material systems. As such, surface passivation is becoming an increasingly important issue as progress is made towards the commercialization of Type-II devices and focal plane array applications. This work focuses on initial attempts at surface passivation of Type-II InAs/GaSb superlattice photodiodes using PECVD-grown thin layers of SiO₂. Our results indicate that silicon dioxide coatings deposited at various temperatures improve photodetector resistivity by several times. Furthermore, reverse-bias dark current has been reduced significantly in passivated devices. [reprint (PDF)]
2.	Ultra-broadband quantum cascade laser, tunable over 760 cm−1, with balanced gain N. Bandyopadhyay, M. Chen, S. Sengupta, S. Slivken, and M. Razeghi Opt. Express 23, 21159-21164 -- August 10, 2015 ...[Visit Journal] A heterogeneous quantum cascade laser, consisting of multiple stacks of discrete wavelength quantum cascade stages, emitting in 5.9-10.9 µm, wavelength range is reported. The broadband characteristics are demonstrated with a distributed-feedback laser array, emitting at fixed frequencies at room temperature, covering an emission range of ~760 cm⁻¹, which is ~59% relative to the center frequency. By appropriate choice of a strained AlInAs/GaInAs material system, quantum cascade stage design and spatial arrangement of stages, the distributed-feedback array has been engineered to exhibit a flat threshold current density across the demonstrated range. [reprint (PDF)]
2.	Single-mode, high-power, midinfrared, quantum cascade laser phased arrays Wenjia Zhou , Donghai Wu , Quan-Yong Lu, Steven Slivken & Manijeh Razeghi Scientific Reports 8:14866-- October 5, 2018 ...[Visit Journal] We demonstrate single-mode, 16-channel, optical phased arrays based on quantum cascade laser technology, with emission wavelengths around 4.8 μm. The integrated device consists of a distributed feedback seed section, a highly-efficient tree array multi-mode interferometer power splitter, and a 16-channel amplifier array with a 4° angled facet termination. With a single layer Y₂O₃ coating, the angled facet reflectivity is estimated to be less than 0.1% for suppressing amplifier self-lasing. A peak output power of 30 W is achieved with an emission spectrum narrower than 11 nm and a side mode suppression ratio over 25 dB. Far field distribution measurement result indicates a uniform phase distribution across the array output. Using the same phased array architecture, we also demonstrate single-mode 3.8 μm QCL amplifier arrays with up to 20 W output power. [reprint (PDF)]
2.	Wafer-scale epitaxial lift-off of optoelectronic grade GaN from a GaN substrate using a sacrificial ZnO interlayer Akhil Rajan, David J Rogers, Cuong Ton-That, Liangchen Zhu, Matthew R Phillips, Suresh Sundaram, Simon Gautier, Tarik Moudakir, Youssef El-Gmili, Abdallah Ougazzaden, Vinod E Sandana, Ferechteh H Teherani, Philippe Bove, Kevin A Prior, Zakaria Djebbour, Ryan McClintock and Manijeh Razeghi Journal of Physics D: Applied Physics, Volume 49, Number 31 -- July 15, 2016 ...[Visit Journal] Full 2 inch GaN epilayers were lifted off GaN and c-sapphire substrates by preferential chemical dissolution of sacrificial ZnO underlayers. Modification of the standard epitaxial lift-off (ELO) process by supporting the wax host with a glass substrate proved key in enabling full wafer scale-up. Scanning electron microscopy and x-ray diffraction confirmed that intact epitaxial GaN had been transferred to the glass host. Depth-resolved cathodoluminescence (CL) analysis of the bottom surface of the lifted-off GaN layer revealed strong near-band-edge (3.33 eV) emission indicating a superior optical quality for the GaN which was lifted off the GaN substrate. This modified ELO approach demonstrates that previous theories proposing that wax host curling was necessary to keep the ELO etch channel open do not apply to the GaN/ZnO system. The unprecedented full wafer transfer of epitaxial GaN to an alternative support by ELO offers the perspective of accelerating industrial adoption of the expensive GaN substrate through cost-reducing recycling. [reprint (PDF)]
2.	Dual section quantum cascade lasers with wide electrical tuning S. Slivken, N. Bandyopadhyay, S. Tsao, S. Nida, Y. Bai, Q.Y. Lu and M. Razeghi SPIE Proceedings, Vol. 8631, p. 86310P-1, Photonics West, San Francisco, CA-- February 3, 2013 ...[Visit Journal] This paper describes our development efforts at Northwestern University regarding dual-section sampled grating distributed feedback (SGDFB) QCLs. These devices are the same size, but have much wider electrical tuning, than a traditional DFB laser. In this paper, I will show how we have dramatically extended the monolithic tuning range of high power quantum cascade lasers with high side mode suppression. This includes individual laser element tuning of up to 50 cm^-1 and 24 dB average side mode suppression. These lasers are capable of room temperature continuous operation with high power (>100 mW) output. Additionally, we have demonstrated a broad spectral coverage of over 350 cm^-1 on a single chip, which is equivalent to 87.5% of the gain bandwidth. The eventual goal is to realize an extended array of such laser modules in order to continuously cover a similar or broader spectral range, similar to an external cavity device without any external components. [reprint (PDF)]
2.	Tunability of intersubband absorption from 4.5 to 5.3 µm in a GaN/Al_0.2Ga_0.8N superlattices grown by metalorganic chemical vapor deposition N. Péré-Laperne, C. Bayram, L. Nguyen-Thê, R. McClintock, and M. Razeghi Applied Physics Letters, Vol. 95, No. 13, p. 131109-- September 28, 2009 ...[Visit Journal] Intersubband (ISB) absorption at wavelengths as long as 5.3 µm is realized in GaN/Al_0.2Ga_0.8N superlattices grown by metalorganic chemical vapor deposition. By employing low aluminum content Al_0.2Ga_0.8N barriers and varying the well width from 2.6 to 5.1 nm, ISB absorption has been tuned from 4.5 to 5.3 µm. Theoretical ISB absorption and interband emission models are developed and compared to the experimental results. The effects of band offsets and the piezoelectric fields on these superlattices are investigated. [reprint (PDF)]
2.	A Review of III-Nitride Research at the Center for Quantum Devices M. Razeghi and R. McClintock Journal of Crystal Growth, Vol. 311, No. 10-- May 1, 2009 ...[Visit Journal] In this paper, we review the history of the Center for Quantum Devices’ (CQD) III-nitride research covering the past 15 years. We review early work developing III-nitride material growth. We then present a review of laser and light-emitting diode (LED) results covering everything from blue lasers to deep UV LEDs emitting at 250 nm. This is followed by a discussion of our UV photodetector research from early photoconductors all the way to current state of the art Geiger-mode UV single photon detectors. [reprint (PDF)]
2.	Hybrid green LEDs based on n-ZnO/(InGaN/GaN) multi-quantum-wells/p-GaN C. Bayram, F. Hosseini Teherani, D.J. Rogers and M. Razeghi SPIE Proceedings, San Jose, CA Volume 7217-0P-- January 26, 2009 ...[Visit Journal] Hybrid green light-emitting diodes (LEDs) comprised of n-ZnO/(InGaN/GaN) multi-quantum-wells/p-GaN were grown on semi-insulating AlN/sapphire using pulsed laser deposition for the n-ZnO and metal organic chemical vapor deposition for the other layers. X-ray diffraction revealed that high crystallographic quality was preserved after the n- ZnO growth. LEDs showed a turn-on voltage of 2.5 V and a room temperature electroluminescence (EL) centered at 510 nm. A blueshift and narrowing of the EL peak with increasing current was attributed to bandgap renormalization. The results indicate that hybrid LED structures could hold the prospect for the development of green LEDs with superior performance. [reprint (PDF)]
2.	Electrically pumped photonic crystal distributed feedback quantum cascade lasers Y. Bai, P. Sung, S.R. Darvish, W. Zhang, A. Evans, S. Slivken, and M. Razeghi SPIE Conference, January 20-25, 2008, San Jose, CA Proceedings – Quantum Sensing and Nanophotonic Devices V, Vol. 6900, p. 69000A-1-8.-- February 1, 2008 ...[Visit Journal] We demonstrate electrically pumped, room temperature, single mode operation of photonic crystal distributed feedback (PCDFB) quantum cascade lasers emitting at ~ 4.75 µm. Ridge waveguides of 50 µm and 100 µm width were fabricated with both PCDFB and Fabry-Perot feedback mechanisms. The Fabry-Perot device has a broad emitting spectrum and a broad far-field character. The PCDFB devices have primarily a single spectral mode and a diffraction limited far field characteristic with a full angular width at half-maximum of 4.8 degrees and 2.4 degrees for the 50 µm and 100 µm ridge widths, respectively. [reprint (PDF)]
2.	Use of ZnO thin films as sacrifical templates for metal organic vapor phase epitaxy and chemical lift-off of GaN D.J. Rogers, F. Hosseini Teherani, A. Ougazzaden, S. Gautier, L. Divay, A. Lusson, O. Durand, F. Wyczisk, G. Garry, T. Monteiro, M.R. Correira, M. Peres, A. Neves, D. McGrouther, J.N. Chapman, and M. Razeghi Applied Physics Letters, Vol. 91, No. 7, p. 071120-1-- August 13, 2007 ...[Visit Journal] Continued development of GaN-based light emitting diodes is being hampered by constraints imposed by current non-native substrates. ZnO is a promising alternative substrate but it decomposes under the conditions used in conventional GaN metal organic vapor phase epitaxy (MOVPE). In this work, GaN was grown on ZnO/c-Al₂O₃ using low temperature/pressure MOVPE with N₂ as a carrier and dimethylhydrazine as a N source. Characterization confirmed the epitaxial growth of GaN. The GaN was lifted-off the c-Al₂O₃ by chemically etching away the ZnO underlayer. This approach opens up the way for bonding of the GaN onto a support of choice. [reprint (PDF)]
2.	Quantum cascade laser: A tool for trace chemical detection Allan J. Evans; Manijeh Razeghi American Filtration and Separations Society - 20th Annual Conference and Exposition of the American Filtration and Separations Society 2:914-923 (2007)-- March 26, 2007 Laser-based trace chemical sensors are highly desired to enhance pollution filtering, health and safety monitoring, and filter efficiency monitoring for industrial processes. Limitations of current monitoring and sensing techniques are discussed and the benefits of mid-infrared spectroscopy using novel Quantum Cascade semiconductor Lasers (QCLs) are presented. These new techniques promise inexpensive, miniaturized sensors, capable of remote detection of trace chemicals in liquids, solids, and gasses with levels less than 1 part-per-billion. Applications of these techniques are discussed and the most recent developments of application-ready high power (> 100 mW), continuous-wave, mid-infrared QCLs operating above room temperature with lifetimes exceeding 12,000 hours are presented.
2.	Electroluminescence at 375 nm from a Zn0/GaN:Mg/c-Al₂O₃ heterojunction light emitting diodes D.J. Rogers, F.Hosseini Teherani, A. Yasan, K. Minder, P. Kung, and M. Razeghi Applied Physics Letters, 88 (14)-- April 13, 2006 ...[Visit Journal] n-ZnO/p-GaN:Mg heterojunction light emitting diode (LED) mesas were fabricated on c-Al₂O₃ substrates using pulsed laser deposition for the ZnO and metal organic chemical vapor deposition for the GaN:Mg. Room temperature (RT) photoluminescence (PL) showed an intense main peak at 375 nm and a negligibly low green emission indicative of a near band edge excitonic emission from a ZnO layer with low dislocation/defect density. The LEDs showed I-V characteristics confirming a rectifying diode behavior and a RT electroluminescence (EL) peaked at about 375 nm. [reprint (PDF)]
2.	GaInAs/InP nanopillar arrays for long wavelength infrared detection A. Gin, Y. Wei, A. Hood, D. Hoffman, M. Razeghi and G.J. Brown SPIE Conference, Jose, CA, Vol. 5732, pp. 350-- January 22, 2005 ...[Visit Journal] Nanopillar devices have been fabricated from GaInAs/InP QWIP material grown by MOCVD. Using electron beam lithography and reactive ion etching techniques, large, regular arrays of nanopillars with controllable diameters ranging from 150 nm to less than 40 nm have been reproducibly formed. Photoluminescence experiments demonstrate a strong peak wavelength blue shift for nanopillar structures compared to the as-grown quantum well material. Top and bottom metal contacts have been realized using a polyimide planarization and etchback procedure. I-V and noise measurements have been performed. Optical measurements indicate photoconductive response in selected nanopillar arrays. Device peak wavelength response occurs at about 8 µm with peak device responsivity of 420 mA/W. Peak detectivity of 3×10⁸ cm·Hz^½/W has been achieved at -1V bias and 30 K. [reprint (PDF)]
2.	Roadmap of Semiconductor Infrared Lasers and Detectors for the 21st Century M. Razeghi SPIE Conference, San Jose, CA, -- January 27, 1999 ...[Visit Journal] Since the first discovery, semiconductor infrared lasers and detectors have found many various applications in military, communications, medical, and industry sections. In this paper, the current status of semiconductor infrared lasers and detectors will be reviewed. Advantages and disadvantages of different methods and techniques is discussed later. Some basic physical limitations of current technology are studied and the direction to overcome these problems will be suggested. [reprint (PDF)]
2.	Intersubband hole absorption in GaAs-GaInP Quantum Wells grown by Gas Source Molecular Beam Epitaxy J. Hoff, C. Jelen, S. Slivken, E. Michel, O. Duchemin, E. Bigan, and M. Razeghi with G. Brown and S.M. Hegde (Wright Laboratory) Applied Physics Letters 65 (9)-- August 29, 1994 ...[Visit Journal] P-doped GaAs‐GaInP quantum wells have been grown on GaAs substrate by gas source molecular beam epitaxy. Structural quality has been evidenced by x-ray diffraction. A narrow low-temperature photoluminescence full width at half‐maximum has been measured. Strong hole intersubband absorption has been observed at 9 μm, and its dependence on light polarization has been investigated. [reprint (PDF)]
2.	Quantum Sensing Using Type-II InAs/GaSb Superlattice for Infrared Detection M. Razeghi, A. Gin, Y. Wei, J. Bae, and J. Nah Microelectronics Journal, 34 (5-8)-- May 1, 2003 ...[Visit Journal] Large, regular arrays of bulk GaSb and InAs/GaSb Type-II superlattice pillars have been fabricated by electron beam lithography and dry etching. A 2.5 keV electron beam lithography system and metal evaporation are used to form the Au mask on superlattice and bulk substrates. Dry etching of these materials has been developed with BCl3:Ar, CH4:H2:Ar and cyclic CH₄:H₂:Ar/O₂ plasmas. Etch temperatures were varied from 20 to 150 °C. The diameter of the superlattice pillars was below 50 nm with regular 200 nm spacing. Bulk GaSb pillars were etched with diameters below 20 nm. Areas of dense nanopillars as large as 500 μm×500 μm were fabricated. The best height/diameter aspect ratio was approximately 10:1. To date, these are the smallest diameter III–V superlattice pillar structures reported, and the first nanopillars in the InAs/GaSb material system. The basic theory of these devices and surface passivation with SiO₂ and Si₃N₄ thin films has also been discussed. [reprint (PDF)]
2.	Continuous wave, room temperature operation of λ ~ 3μm quantum cascade laser N. Bandyopadhyay, Y. Bai, S. Tsao, S. Nida, S. Slivken and M. Razeghi SPIE Proceedings, Vol. 8631, p. 86310M-1, Photonics West, San Francisco, CA-- February 3, 2013 ...[Visit Journal] Quantum Cascade Lasers (QCLs), operating in continuous wave (CW) at room temperature(RT) in 3-3.5 μm spectral range, which overlaps the spectral fingerprint region of many hydrocarbons, is essential in spectroscopic trace gas detection, environment monitoring, and pollution control. A 3 μm QCL, operating in CW at RT is demonstrated. This initial result makes it possible, for the most popular material system (AlInAs/GaInAs on InP) used in QCLs in mid-infrared and long-infrared, to cover the entire spectral range of mid-infrared atmospheric window (3-5 μm). In_0.79Ga_0.21As/In_0.11Al_0.89As strain balanced superlattice, which has a large conduction band offset, was grown. The strain was balanced with composite barriers (In_0.11Al_0.89As /In_0.4Al_0.6As) in the injector region, to eliminate the need of extremely high compressively strained GaInAs, whose pseudomorphic growth is very difficult. [reprint (PDF)]
2.	Tight-binding theory for the thermal evolution of optical band gaps in semiconductors and superlattices S. Abdollahi Pour, B. Movaghar, and M. Razeghi American Physical Review, Vol. 83, No. 11, p. 115331-1-- March 15, 2011 ...[Visit Journal] A method to handle the variation of the band gap with temperature in direct band-gap III–V semiconductors and superlattices using an empirical tight-binding method has been developed. The approach follows closely established procedures and allows parameter variations which give rise to perfect fits to the experimental data. We also apply the tight-binding method to the far more complex problem of band structures in Type-II infrared superlattices for which we have access to original experimental data recently acquired by our group. Given the close packing of bands in small band-gap Type-II designs, k·p methods become difficult to handle, and it turns out that the sp3s* tight-binding scheme is a practical and powerful asset. Other approaches to band-gap shrinkage explored in the past are discussed, scrutinized, and compared. This includes the lattice expansion term, the phonon softening mechanism, and the electron-phonon polaronic shifts calculated in perturbation theory. [reprint (PDF)]
2.	High performance quantum dot-quantum well infrared focal plane arrays S. Tsao, A. Myzaferi, and M. Razeghi SPIE Proceedings, San Francisco, CA (January 22-28, 2010), Vol. 7605, p. 76050J-1-- January 27, 2010 ...[Visit Journal] Quantum dot (QD) devices are a promising technology for high operating temperature detectors. We have studied InAs QDs embedded in an InGaAs/InAlAs quantum well structure on InP substrate for middle wavelength infrared detectors and focal plane arrays (FPAs). This combined dot-well structure has weak dot confinement of carriers, and as a result, the device behavior differs significantly from that in more common dot systems with stronger confinement. We report on our studies of the energy levels in the QDWIP devices and on QD-based detectors operating at high temperature with D* over 10¹⁰ cm·Hz^½/W at 150 K operating temperature and high quantum efficiency over 50%. FPAs have been demonstrated operating at up to 200 K. We also studied two methods of adapting the QDWIP device to better accommodate FPA readout circuit limitations. [reprint (PDF)]

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