Center for Quantum Devices - Most Downloaded Journal Articles

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12.	Miniaturization: enabling technology for the new millennium M. Razeghi and H. Mohseni SPIE International Conference on Solid State Crystals, Zakopane, Poland, -- April 1, 2001 ...[Visit Journal] The history of semiconductor devices has been characterized by a constant drive toward lower dimensions in order to increase integration density, system functionality and performance. However, this is still far from being comparable with the performance of natural systems such as human brain. The challenges facing semiconductor technologies in the millennium will be to move toward miniaturization. The influence of this trend on the quantum sensing of infrared radiation is one example that is elaborated here. A new generation of infrared detectors has been developed by growing layers of different semiconductors with nanometer thicknesses. The resulted badgap engineered semiconductor has superior performance compared to the bulk material. To enhance this technology further, we plan to move from quantum wells to quantum wire and quantum dots. [reprint (PDF)]
12.	High-performance, continuous-wave operation of λ ~ 4.6 μm quantum-cascade lasers above room temperature J.S. Yu, S. Slivken, A. Evans and M. Razeghi IEEE Journal of Quantum Electronics, Vol. 44, No. 8, p. 747-754-- August 1, 2008 ...[Visit Journal] We report the high-performance continuous-wave (CW) operation of 10-μm-wide quantum-cascade lasers (QCLs) emitting at λ ~ 4.6 μm, based on the GaInAs–AlInAs material without regrowth, in epilayer-up and -down bonding configurations. The operational characteristics of QCLs such as the maximum average power, peak output power, CW output power, and maximum CW operating temperature are investigated, depending on cavity length. Also, important device parameters, i.e., the waveguide loss, the transparency current density, the modal gain, and the internal quantum efficiency, are calculated from length-dependent results. For a high-reflectivity (HR) coated 4-mm-long cavity with epilayer-up bonding, the highest maximum average output power of 633 mW is measured at 65% duty cycle, with 469 mW still observed at 100%. The laser exhibits the maximum wall-plug efficiencies of 8.6% and 3.1% at 298 K, in pulsed and CW operatons, respectively. From 298 to 393 K, the temperature dependent threshold current density in pulsed operation shows a high characteristic temperature of 200 K. The use of an epilayer-down bonding further improves the device performance. A CW output power of 685 mW at 288 K is achieved for the 4-micron-long cavity. At 298 K, the output power of 590 mW, threshold current density of 1.52 kA / cm2, and maximum wall-plug efficiency of 3.73% are obtained under CW mode, operating up to 363 K (90 °C). For HR coated 3-micron-long cavities, laser characteristics across the same processed wafer show a good uniformity across the area of 2 x 1 cm², giving similar output powers, threshold current densities, and emission wavelengths. The CW beam full-width at half-maximum of far-field patterns are 25 degree and 46 degree for the parallel and the perpendicular directions, respectively. [reprint (PDF)]
12.	Stranski-Krastanov growth of InGaN quantum dots emitting in green spectra C. Bayram and M. Razeghi Applied Physics A: Materials Science and Processing, Vol. 96, No. 2, p. 403-408-- August 1, 2009 ...[Visit Journal] Self-assembled InGaN quantum dots (QDs) were grown on GaN templates by metalorganic chemical vapor deposition. 2D–3D growth mode transition through Stranski–Krastanov mode was observed via atomic force microscopy. The critical thickness for In_0.67Ga_0.33N QDs was determined to be four monolayers. The effects of growth temperature, deposition thickness, and V/III ratio on QD formation were examined. The capping of InGaN QDs with GaN was analyzed. Optimized InGaN quantum dots emitted in green spectra at room temperature. [reprint (PDF)]
12.	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)]
12.	Noise analysis in type-II InAs/GaSb focal plane arrays P.Y. Delaunay and M. Razeghi Journal of Applied Physics, Vol. 106, Issue 6, p. 063110-- September 15, 2009 ...[Visit Journal] A long wavelength infrared focal plane array based on type-II InAs/GaSb superlattices was fabricated and characterized at 80 K. The noise equivalent temperature difference in the array was measured as low as 23 mK for an integration time of 0.129 ms. The noise behavior of the detectors was properly described by a model based on thermal, shot, read out integrated circuit, and photon noises. The noise of the imager was dominated by photon noise for photon fluxes higher than 1.8×10¹⁵ ph·s⁻¹·cm⁻². At lower irradiance, the imager was limited by the shot noise generated by the dark current or the noise of the testing system. The superlattice detector did not create 1/f noise for frequencies above 4 mHz. As a result, the focal plane array did not require frequent calibrations. [reprint (PDF)]
12.	The new oxide paradigm for solid state ultraviolet photodetectors D. J. Rogers, P. Bove, X. Arrateig, V. E. Sandana, F. H. Teherani, M. Razeghi, R. McClintock, E. Frisch, S. Harel, Proceedings Volume 10533, Oxide-based Materials and Devices IX; 105331P-- March 22, 2018 ...[Visit Journal] The bandgap of wurzite ZnO layers grown on 2 inch diameter c-Al₂O₃ substrates by pulsed laser deposition was engineered from 3.7 to 4.8 eV by alloying with Mg. Above this Mg content the layers transformed from single phase hcp to mixed hcp/fcc phase before becoming single phase fcc above a bandgap of about 5.5 eV. Metal-Semiconductor-Metal (MSM) photodetectors based on gold Inter-Digitated-Transducer structures were fabricated from the single phase hcp layers by single step negative photolithography and then packaged in TO5 cans. The devices gave over 6 orders of magnitude of separation between dark and light signal with solar rejection ratios (I270 : I350) of over 3 x 10⁵ and dark signals of 300 pA (at a bias of −5V). Spectral responsivities were engineered to fit the “Deutscher Verein des Gas- und Wasserfaches” industry standard form and gave over two decade higher responsivities (14 A/W, peaked at 270 nm) than commercial SiC based devices. Homogeneous Ga₂O₃ layers were also grown on 2 inch diameter c-Al₂O₃ substrates by PLD. Optical transmission spectra were coherent with a bandgap that increased from 4.9 to 5.4 eV when film thickness was decreased from 825 to 145 nm. X-ray diffraction revealed that the films were of the β-Ga₂O₃ (monoclinic) polytype with strong (−201) orientation. β-Ga₂O₃ MSM photodetectors gave over 4 orders of magnitude of separation between dark and light signal (at −5V bias) with dark currents of 250 pA and spectral responsivities of up to 40 A/W (at -0.75V bias). It was found that the spectral responsivity peak position could be decreased from 250 to 230 nm by reducing film thickness from 825 to 145 nm. This shift in peak responsivity wavelength with film thickness (a) was coherent with the apparent bandgap shift that was observed in transmission spectroscopy for the same layers and (b) conveniently provides a coverage of the spectral region in which MgZnO layers show fcc/hcp phase mixing. [reprint (PDF)]
12.	Reliability of strain-balanced Ga_0.331In_0.669As/Al_0.659In_0.341As/InP quantum-cascade lasers under continuous-wave room-temperature operation A. Evans and M. Razeghi Applied Physics Letters, 88 (26)-- June 26, 2006 ...[Visit Journal] Constant current aging is reported for two randomly selected high-reflectivity-coated QCLs with an output power over 100 mW. QCLs are tested under continuous-wave operation at a heat sink temperature of 298 K(25 °C) corresponding to an internal temperature of 378 K (105 °C). Over 4000 h of continuous testing is reported without any decrease in output power. [reprint (PDF)]
12.	Minority electron unipolar photodetectors based on Type-II InAs/GaSb/AlSb superlattices for very long wavelength infrared detection B.M. Nguyen, S. Bogdanov, S. Abdollahi Pour, and M. Razeghi Applied Physics Letters, Vol. 95, No. 18, p. 183502-- November 2, 2009 ...[Visit Journal] We present a hybrid photodetector design that inherits the advantages of traditional photoconductive and photovoltaic devices. The structure consists of a barrier layer blocking the transport of majority holes in a p-type semiconductor, resulting in an electrical transport due to minority carriers with low current density. By using the M-structure superlattice as a barrier region, the band alignments can be experimentally controlled, allowing for the efficient extraction of the photosignal with less than 50 mV bias. At 77 K, a 14 µm cutoff detector exhibits a dark current 3.3 mA·cm⁻², a photoresponsivity of 1.4 A/W, and the associated shot noise detectivity of 4×10¹⁰ Jones. [reprint (PDF)]
12.	Progress in monolithic, broadband, widely tunable midinfrared quantum cascade lasers Manijeh Razeghi Wenjia Zhou Ryan McClintock Donghai Wu Steven Slivken Optical Engineering 57(1), 011018-- December 1, 2017 ...[Visit Journal] We present recent progress on the development of monolithic, broadband, widely tunable midinfrared quantum cascade lasers. First, we show a broadband midinfrared laser gain realized by a heterogeneous quantum cascade laser based on a strain balanced composite well design of Al_0.63In_0.37As∕Ga_0.35In_0.65As∕ Ga_0.47In_0.53As. Single mode emission between 5.9 and 10.9 μm under pulsed mode operation was realized from a distributed feedback laser array, which exhibited a flat current threshold across the spectral range. Using the broadband wafer, a monolithic tuning between 6.2 and 9.1 μm was demonstrated from a beam combined sampled grating distributed feedback laser array. The tunable laser was utilized for a fast sensing of methane under pulsed operation. Transmission spectra were obtained without any moving parts, which showed excellent agreement to a standard measurement made by a Fourier transform infrared spectrometer. [reprint (PDF)]
12.	High‐quality GaAs/Ga0.49In0.51P superlattices grown on GaAs and silicon substrates by low‐pressure metalorganic chemical vapor deposition Available M. Razeghi; Ph. Maurel; F. Omnes; M. Defour; C. Boothroyd; W. M. Stobbs; M. Kelly J. Appl. Phys. 63, 4511–4514 (1988) -- May 1, 1988 ...[Visit Journal] We report the successful growth of Ga0.49 Iuo.5 ! P-GaAs superlattices on GaAs and Si substrates by low-pressure metalorganic chemical vapor deposition. The high quality of the structure grown on GaAs and silicon substrates has been evidenced by transmission electron microscopy photographs, that show very sharp interfaces between GaAs wells and Gao.49InO.51 P barriers, with perfect control of thicknesses and compositions. Classical Hall measurements performed on the sample further demonstrated the presence of a twodimensional electron ga.<; with a mobility at T = 4 K , fL (4 K) = 50000 cm2 1V Is, and a carrier concentration n _ (4 K) = 2,9 X 1011 em -2. GaAs/Gao.49 InO. 51 P superlattices have been used, as well as buffer layer in order to grow GaAs on silicon substrates. Mirrorlike single-crystal GaAs has thus been obtained. A GaInP IGaAs heterostructure with electron HaH mobility as high as 6000 cm2 /V Is at 300 K and 80000 cm2 /V Is at 4 K has been grown, which is the highest mobility that has yet been reported for these materials, [reprint (PDF)]
12.	Characterization and Analysis of Single-Mode High-Power CW Quantum-Cascade Laser W.W. Bewley, I. Vurgaftman, C.S. Kim, J.R. Meyer, J. Nguyen, A. Evans, J.S. Yu, S.R. Darvish, S. Slivken, and M. Razeghi Journal of Applied Physics 98-- October 15, 2005 ...[Visit Journal] We measured and modeled the performance characteristics of a distributed-feedback quantum-cascade laser exhibiting high-power continuous-wave (CW) operation in a single spectral mode at λ~4.8 µm and temperatures up to 333 K. The sidemode suppression ratio exceeds 25 dB, and the emission remains robustly single mode at all currents and temperatures tested. CW output powers of 99 mW at 298 K and 357 mW at 200 K are obtained at currents well below the thermal rollover point. The slope efficiency and subthreshold amplified spontaneous emission spectra are shown to be consistent with a coupling coefficient of no more than κL ~ 4–5, which is substantially lower than the estimate of 9 based on the nominal grating fabrication parameters. [reprint (PDF)]
12.	Gain-length scaling in quantum dot/quantum well infrared photodetectors T. Yamanaka, B. Movaghar, S. Tsao, S. Kuboya, A. Myzaferi and M. Razeghi Applied Physics Letters, Vol. 95, No. 9-- August 31, 2009 ...[Visit Journal] The gain in quantum dot/quantum well infrared photodetectors is investigated. The scaling of the gain with device length has been analyzed, and the behavior agrees with the previously proposed model. We conclude that we understand the gain in the low bias region, but in the high field region, discrepancies remain. An extension of the gain model is presented to cover the very high electric field region. The high field data are compared to the extended model and discussed. [reprint (PDF)]
12.	AlGaN/AlN MOVPE heteroepitaxy: pulsed co-doping SiH4 and TMIn Ilkay Demir, Yusuf Koçak, A. Emre Kasapoğlu, Manijeh Razeghi, Emre Gür and Sezai Elagoz Semicond. Sci. Technol. 34 075028-- June 24, 2019 ...[Visit Journal] We report a new growth approach pulsed co-doping growth of Al_xGa_1−xN (x > 0.5) epilayers on AlN/Al₂O₃ templates by metal organic vapor phase epitaxy (MOVPE). Using this approach SiH₄ (silane) and TMIn (trimethylindium) supplied to the growth chamber alternately and pulsed during the growth of AlGaN epilayers. Structural and morphological quality of AlGaN epilayers were investigated by high resolution x-ray diffraction (HR-XRD), atomic force microscopy (AFM), Raman spectroscopy, and scanning electron microscopy (SEM) techniques. It has shown that higher crystalline quality with low full width at half maximum (FWHM) and smoother surface morphology with reduced hexagonal hillock density has been obtained by the pulsed co-doping growth approach. Volcano like hillock structures has been confirmed by Raman mapping. [reprint (PDF)]
12.	Stable single mode terahertz semiconductor sources at room temperature M. Razeghi 2011 International Semiconductor Device Research Symposium, ISDRS [6135180] (2011).-- December 7, 2011 ...[Visit Journal] Terahertz (THz) range is an area of the electromagnetic spectra which has lots of applications but it suffers from the lack of simple working devices which can emit THz radiation, such as the high performance mid-infrared (mid-IR) quantum cascade lasers (QCLs) based on InP technology. The applications for the THz can be found in astronomy and space research, biology imaging, security, industrial inspection, etc. Unlike THz QCLs based on the fundamental oscillators, which are limited to cryogenic operations, semiconductor THz sources based on nonlinear effects of mid-IR QCLs do not suffer from operating temperature limitations, because mid-IR QCLs can operate well above room temperature. THz sources based on difference frequency generation (DFG) utilize nonlinear properties of asymmetric quantum structures, such as QCL structures. [reprint (PDF)]
12.	Ultraviolet avalanche photodiodes Ryan McClintock ; Manijeh Razeghi Proc. SPIE 9555, Optical Sensing, Imaging, and Photon Counting: Nanostructured Devices and Applications, 95550B -- August 28, 2015 ...[Visit Journal] The III-Nitride material system is rapidly maturing; having proved itself as a material for LEDs and laser, and now finding use in the area of UV photodetectors. However, many UV applications are still dominated by the use of photomultiplier tubes (PMT). PMTs are capable of obtaining very high sensitivity using internal electron multiplication gain (typically ~106). It is highly desirable to develop a compact semiconductor-based photodetector capable of realizing this level of sensitivity. In principle, this can be obtained in III-Nitrides by taking advantage of avalanche multiplication under high electric fields – typically 2.7 MV/cm, which with proper design can correspond to an external reverse bias of less than 100 volts. In this talk, we review the current state-of-the-art in III-Nitride solar- and visible-blind APDs, and present our latest results on GaN APDs grown on both conventional sapphire and low dislocation density free-standing c- and m-plane GaN substrates. Leakage current, gain, and single photon detection efficiency (SPDE) of these APDs were compared. The spectral response and Geiger-mode photon counting performance of UV APDs are studied under low photon fluxes, with single photon detection capabilities as much as 30% being demonstrated in smaller devices. Geiger-mode operation conditions are optimized for enhanced SPDE. [reprint (PDF)]
12.	High-power InGaAsP/GaAs 0.8 μm laser diodes and peculiarities of operational characteristics J. Diaz, I. Eliashevich, X. He, H. Yi, L. Wang, E. Kolev, D. Garbuzov, and M. Razeghi Applied Physics Letters 65 (8)-- August 22, 1994 ...[Visit Journal] High-power operation of 3 W in pulse mode, 750 mW in quasi-continuous wave and 650 mW in continuous wave per uncoated facet from 100 μm aperture has been demonstrated for 1 mm long cavity InGaAsP/GaAs 808 nm laser diodes prepared by low-pressure metalorganic chemical vapor deposition. Threshold current density of 300 A/cm², differential efficiency of 1.1 W/A, T₀=155 °C, transverse beam divergence of 27°, and less than 2 nm linewidth at 808 nm have been measured. No degradation has been observed after 1000 h of operation in a quasi-continuous wave regime. [reprint (PDF)]
12.	MOCVD Growth of ZnO Nanostructures Using Au Droplets as Catalysts V.E. Sandana, D.J. Rogers, F.H. Teherani, R. McClintock, M. Razeghi, H.J. Drouhin, M.C. Clochard, V. Sallett, G. Garry and F. Fayoud SPIE Conference, January 20-25, 2008, San Jose, CA Proceedings – Zinc Oxide Materials and Devices III, Vol. 6895, p. 68950Z-1-6.-- February 1, 2008 ...[Visit Journal] ZnO nanostructures were synthesised by Metal Organic Chemical Vapor Deposition growth on Si (100) and c-Al₂O₃ substrates coated with a 5nm thick layer of Au. The Au coated substrates were annealed in air prior to deposition of ZnO so as to promote formation of Au nanodroplets. The development of the nanodroplets was studied as a function of annealing duration and temperature. Under optimised conditions, a relatively homogeneous distribution of regular Au nanodroplets was obtained. Using the Au nanodroplets as a catalyst, MOCVD growth of ZnO nanostructures was studied. Scanning electron microscopy revealed nanostructures with various forms including commonly observed structures such as nanorods, nanoneedles and nanotubes. Some novel nanostructures were also observed, however, which resembled twist pastries and bevelled-multifaceted table legs. [reprint (PDF)]
11.	Planar nBn type-II superlattice mid-wavelength infrared photodetectors using zinc ion-implantation Arash Dehzangi, Donghai Wu, Ryan McClintock, Jiakai Li, and Manijeh Razeghi Appl. Phys. Lett. 116, 221103 https://doi.org/10.1063/5.0010273-- June 2, 2020 ...[Visit Journal] In this Letter, we report the demonstration of zinc ion-implantation to realize planar mid-wavelength infrared photodetectors based on type-II InAs/InAs1−xSbx superlattices. At 77 K, the photodetectors exhibit a peak responsivity of 0.68 A/W at 3.35 μm, corresponding to a quantum efficiency of 23.5% under Vb = −80 mV, without anti-reflection coating; these photodetectors have a 100% cutoff wavelength of 4.28 μm. With an R0 × A value of 1.53 × 104 Ω cm2 and a dark current density of 1.23 × 10−6 A/cm2 under an applied bias of −80 mV at 77 K, the photodetectors exhibit a specific detectivity of 9.12 × 1011 cm·Hz1/2/W. [reprint (PDF)]
11.	High performance quantum cascade lasers (~11 μm) operating at high temperature (T>= 425K) A. Tahraoui, A. Matlis, S. Slivken, J. Diaz, and M. Razeghi Applied Physics Letters 78 (4)-- January 22, 2001 ...[Visit Journal] We report record-low threshold current density and high output power for λ ∼ 11 μm Al_0.48In_0.52As/Ga_0.47In_0.53As quantum cascade lasers operating up to 425 K. The threshold current density is 1.1, 3.83, and 7.08 kA/cm² at 80, 300, and 425 K, respectively, for 5 μs pulses at a 200 Hz repetition rate. The cavity length is 3 mm with a stripe width of 20 μm. The maximum peak output power per facet is 1 W at 80 K, 0.5 W at 300 K, and more than 75 mW at 425 K. The characteristic temperature of these lasers is 174 K between 80 and 300 K and 218 K in the range of 300–425 K. [reprint (PDF)]
11.	Top-emission ultraviolet light-emitting diodes with peak emission at 280 nm A. Yasan, R. McClintock, K. Mayes, S.R. Darvish, P. Kung, and M. Razeghi Virtual Journal of Nanoscale Science & Technology, 5-- August 5, 2002 ...[Visit Journal][reprint (PDF)]
11.	High-performance, continuous-wave quantum-cascade lasers operating up to 85° C at λ ~ 8.8 μm J.S. Yu, S. Slivken, A. Evans, and M. Razeghi Applied Physics A: Materials Science & Processing, Vo. 93, No. 2, p. 405-408-- November 1, 2008 ...[Visit Journal] High-temperature, high-power, and continuous-wave (CW) operation of quantum-cascade lasers with 35 active/injector stages at λ∼8.85 μm above room temperature is achieved without using a buried heterostructure. At this long wavelength, the use of a wider ridge waveguide in an epilayer-down bonding scheme leads to a superior performance of the laser. For a high-reflectivity-coated 21 μm×3 mm laser, the output power of 237 mW and the threshold current density of 1.44 kA·cm^-2 at 298 K under CW mode are obtained with a maximum wall-plug efficiency of 1.7%. Further improvements were observed by using a 4-mm-long cavity. The device exhibits 294 mW of output power at 298 K and it operates at a high temperature, even up to 358 K (85°C). The full widths at half-maximum of the laser beam in CW operation for the parallel and the perpendicular far-field patterns are 25°and 63°, respectively. [reprint (PDF)]
11.	High quality LEO growth and characterization of GaN films on Al₂O₃ and Si substrates M. Razeghi, P. Kung, D. Walker, M. Hamilton, and J. Diaz SPIE International Conference on Solid State Crystals, Zakopane, Poland; Proceedings 3725-- October 12, 1998 ...[Visit Journal] We report the lateral epitaxial overgrowth (LEO) of GaN films on (00.1) Al₂O₃ and (111) Si substrates by metalorganic chemical vapor deposition. The LEO on Si substrates was possible after achieving quasi monocrystalline GaN template films on (111) Si substrates. X-ray diffraction, photoluminescence, scanning electron microscopy and atomic force microscopy were used to assess the quality of the LEO films. Lateral growth rates more than 5 times as high as vertical growth rates were achieved for both LEO growths of GaN on sapphire and silicon substrates. [reprint (PDF)]
11.	Geiger-mode operation of back-illuminated GaN avalanche photodiodes J. L. Pau, R. McClintock, K. Minder, C. Bayram, P. Kung, M. Razeghi, E. Muñoz, and D. Silversmith Applied Physics Letters, Vol. 91, No. 04, p. 041104 -1-- July 23, 2007 ...[Visit Journal] We report the Geiger-mode operation of back-illuminated GaN avalanche photodiodes fabricated on transparent AlN templates specifically for back illumination in order to enhance hole-initiated multiplication. The spectral response in Geiger-mode operation was analyzed under low photon fluxes. Single photon detection capabilities were demonstrated in devices with areas ranging from 225 to 14,063 µm². Single photon detection efficiency of 20% and dark count rate < 10 kHz were achieved in the smallest devices. [reprint (PDF)]
11.	Gain and recombination dynamics of quantum-dot infrared photodetecto H. Lim, B. Movaghar, S. Tsao, M. Taguchi, W. Zhang, A.A. Quivy, and M. Razeghi Virtual Journal of Nanoscale Science & Technology-- December 4, 2006 ...[Visit Journal][reprint (PDF)]
11.	Stability of far fields in double heterostructure and multiple quantum well InAsSb/InPAsSb/InAs midinfrared lasers H. Yi, A. Rybaltowski, J. Diaz, D. Wu, B. Lane, Y. Xiao, and M. Razeghi Applied Physics Letters 70 (24)-- June 16, 1997 ...[Visit Journal] Far fields in perpendicular direction to the junction are investigated in double heterostructure (DH) and multiple quantum well (MQW) midwave-infrared InAsSb/InPAsSb/InAs lasers (λ = 3.2–3.6 μm). Strong broadening of the far fields in the DH lasers was observed with increases in temperature and/or current. On the contrary, MQW lasers with otherwise identical structure exhibit very stable far fields as narrow as 23° for all the operating conditions investigated. Our experiment and theoretical modeling suggest that these different behaviors of far fields in DH and MQW lasers are attributed to the refractive index fluctuation in the InAsSb laser active region. [reprint (PDF)]

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