Center for Quantum Devices - Most Downloaded Journal Articles

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13.	Negative luminescence of long-wavelength InAs/GaSb superlattice photodiodes D. Hoffman, A. Hood, Y. Wei, A. Gin, F. Fuchs, and M. Razeghi Applied Physics Letters 87 (20)-- November 14, 2005 ...[Visit Journal] The electrically pumped emission behavior of binary type-II InAs/GaSb superlattice photodiodes has been studied in the spectral range between 8 µm and 13 µm. With a radiometric calibration of the experimental setup, the internal and external quantum efficiency has been determined in the temperature range between 80 K and 300 K for both, the negative and positive luminescence. The negative luminescence efficiency approaches values as high as 35% without antireflection coating. The temperature dependence of the internal quantum efficiency near zero-bias voltage allows for the determination of the electron-hole-electron Auger recombination coefficient of Γ_n=1×10²⁴ cm⁶ s^–1. [reprint (PDF)]
13.	Two‐dimensional electron gases in quantum well and superlattices of Ga0.25In0.75As0.50P0.50/InP heterostructures grown by low pressure metalorganic chemical vapor deposition M. Razeghi; J. P. Duchemin; J. C. Portal Appl. Phys. Lett. 46 (1): 46–48 (1985)-- January 1, 1985 ...[Visit Journal] We report the first observation of a two‐dimensional electron gas from Shubnikov–de Haas experiments, in a Ga0.25In0.75As0.50P0.50‐InP heterojunction, multi‐quantum well, and superlattices grown by metalorganic chemical vapor deposition at reduced pressure. [reprint (PDF)]
13.	Quantum dot in a well infrared photodetectors for high operating temperature focal plane arrays S. Tsao, T. Yamanaka, S. Abdollahi Pour, I-K Park, B. Movaghar and M. Razeghi SPIE Proceedings, San Jose, CA Volume 7234-0V-- January 25, 2009 ...[Visit Journal] InAs quantum dots embedded in InGaAs quantum wells with InAlAs barriers on InP substrate grown by metalorganic chemical vapor deposition are utilized for high operating temperature detectors and focal plane arrays in the middle wavelength infrared. This dot-well combination is unique because the small band offset between the InAs dots and the InGaAs well leads to weak dot confinement of carriers. As a result, the device behavior differs significantly from that in the more common dot systems that have stronger confinement. Here, we present energy level modeling of our QD-QW system and apply these results to interpret the detector behavior. Detectors showed high performance with D* over 10¹⁰ cm·Hz^1/2W^-1 at 150 K operating temperature and with high quantum efficiency over 50%. Focal plane arrays have been demonstrated operating at high temperature due to the low dark current observed in these devices. [reprint (PDF)]
13.	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)]
13.	Room-temperature, high-power and continuous-wave operation of distributed-feedback quantum-cascade lasers at λ ~ 9.6 µm S.R. Darvish, S. Slivken, A. Evans, J.S. Yu, and M. Razeghi Applied Physics Letters, 88 (20)-- May 15, 2006 ...[Visit Journal] High-power continuous-wave (cw) operation of distributed-feedback quantum-cascade lasers is reported. Continuous-wave output powers of 100 mW at 25 °C and 20 mW at 50 °C are obtained. The device exhibits a cw threshold current density of 1.34 kA/cm², a maximum cw wall-plug efficiency of 1% at 25 °C, and a characteristic temperature of ~190 K in pulsed mode. Single-mode emission near 9.6 μm with a side-mode suppression ratio of ≥ 30 dB and a tuning range of 2.89 cm^–1 from 15 to 50 °C is obtained. [reprint (PDF)]
13.	Pressure-induced depopulation of the first excited subband in GaInAs/InP heterojunctions D Gauthier, J C Portal and M Razeghi D Gauthier et al 1989 Semicond. Sci. Technol. 4 218-- December 8, 1988 ...[Visit Journal] Following our previous work on (GalnAs)/(lnP) heterojunctions under hydrostatic pressure we present recent experimental results where the evidence for the total depopulation of the first excited electric subband with pressure is demonstrated. The total electron concentration decreases at a rate of 2.7% kbar”, much higher than in previous experiments. The experimental situation can be fitted with the triangular-well approximation if we both assume the change with pressure of the conduction band discontinuity AE, and the deepening of a deep impurity level with activation energy of the order 160 meV at zero pressure. [reprint (PDF)]
13.	High Power 3-12 μm Infrared Lasers: Recent Improvements and Future Trends M. Razeghi, S. Slivken, A. Tahraoui, A. Matlis, and Y.S. Park Advanced Research Workshop on Semiconductor Nanostructures, Queenstown, New Zealand; Proceedings -- February 5, 2003 ...[Visit Journal] In this paper, we discuss the progress of quantum cascade lasers (QCLs) grown by gas-source molecular beam epitaxy. Room temperature QCL operation has been reported for lasers emitting between 5-11 μm, with 9-11 μm lasers operating up to 425 K. Laser technology for the 3-5 μm range takes advantage of a strain-balanced active layer design. We also demonstrate record room temperature peak output powers at 9 and 11 μm (2.5 and 1 W, respectively) as well as record low 80K threshold current densities (250 A/cm²) for some laser designs. Preliminary distributed feedback (DFB) results are also presented and exhibit single mode operation for 9 μm lasers at room temperature. [reprint (PDF)]
13.	Room temperature continuous wave operation of quantum cascade lasers with watt-level optical power Y. Bai, S.R. Darvish, S. Slivken, W. Zhang, A. Evans, J. Nguyen and M. Razeghi Applied Physics Letters, Vol. 92, No. 10, p. 101105-1-- March 10, 2008 ...[Visit Journal] We demonstrate quantum cascade lasers at an emitting wavelength of 4.6 µm, which are capable of room temperature, high power continuous wave (cw) operation. Buried ridge geometry with a width of 9.8 µm was utilized. A device with a 3 mm cavity length that was epilayer-down bonded on a diamond submount exhibited a maximum output power of 1.3 W at room temperature in cw operation. The maximum output power at 80 K was measured to be 4 W, with a wall plug efficiency of 27%. [reprint (PDF)]
13.	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)]
13.	Spatial Noise and Correctability of Type-II InAs/GaSb Focal Plane Arrays P.Y. Delaunay and M. Razeghi IEEE Journal of Quanutm Electronics, April 2010, Vol. 46, No. 4, p. 584-588-- April 1, 2010 ...[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 of the array was measured as low as 23 mK (f# = 2), for an integration time of 0.129 ms. The spatial noise of the array was dominated by the nonuniformity of the illumination through the circular aperture. A standard two-point nonuniformity correction improved the inhomogeneity equivalent temperature difference to 16 mK. The correctability just after calibration was 0.6. The long-term stability time was superior to 25 hours. [reprint (PDF)]
13.	InAsSb/InAsP strained-layer superlattice injection lasers operating at 4.0 μm grown by metal-organic chemical vapor deposition B. Lane, Z. Wu, A. Stein, J. Diaz, and M. Razeghi Applied Physics Letters 74 (23)-- June 7, 1999 ...[Visit Journal] We report high power mid-infrared electrical injection operation of laser diodes based on InAsSb/InAsP strained-layer superlattices grown on InAs substrate by metal-organic chemical vapor deposition. The broad-area laser diodes with 100 μm aperture and 1800 μm cavity length demonstrate peak output powers of 546 and 94 mW in pulsed and cw operation respectively at 100 K with a threshold current density as low as 100 A/cm². [reprint (PDF)]
13.	First room‐temperature cw operation of a GaInAsP/InP light‐emitting diode on a silicon substrate M. Razeghi; R. Blondeau; M. Defour; F. Omnes; P. Maurel; F. Brillouet Appl. Phys. Lett. 53, 854–855 (1988)-- July 4, 1988 ...[Visit Journal] We report in this letter the first successful fabrication of an InP-GalnAsP light-emitting diode, emitting at 1.15 pm grown by low-pressure metalorganic chemical vapor deposition on a silicon substrate. The device has been operated under continuous wave operation at room temperature for 24 h (with an injection current of 200 rnA), and showed no degradation. [reprint (PDF)]
13.	Study on the effects of minority carrier leakage in InAsSb/InPAsSb double heterostructure B. Lane, D. Wu, H.J. Yi, J. Diaz, A. Rybaltowski, S. Kim, M. Erdtmann, H. Jeon and M. Razeghi Applied Physics Letters 70 (11)-- April 17, 1997 ...[Visit Journal] InAs_xSb_1−x/InP_1−x−yAs_xSb_y double heterostructures have been grown on InAs substrates by metal-organic chemical vapor deposition. The minority carrier leakage to the cladding layers was studied with photoluminescence measurements on the InAsSb/InPAsSb double heterostructures. A carrier leakage model is used to extract parameters related to the leakage current (diffusion-coefficient and length) from experimental results. Using the obtained parameters, the temperature dependence of the threshold current density of InAsSb/InPAsSb double heterostructure lasers is predicted and compared with experimental results. [reprint (PDF)]
13.	Modeling the electronic band-structure of strained long-wavelength Type-II superlattices using the scattering matrix method Abbas Haddadi，Gail Brown，Manijeh Razeghi J Infrared Millim W 44 (3), 346 (2025) ...[Visit Journal] This study introduces a comprehensive theoretical framework for accurately calculating the electronic band-structure of strained long-wavelength InAs/GaSb type-II superlattices. Utilizing an eight-band k ⋅ p Hamilto⁃ nian in conjunction with a scattering matrix method， the model effectively incorporates quantum confinement， strain effects， and interface states. This robust and numerically stable approach achieves exceptional agreement with experimental data， offering a reliable tool for analyzing and engineering the band structure of complex multi⁃ layer systems [reprint (PDF)]
13.	On the Description of the Collision Terms in Three-Valley Hydrodynamic Models for GaAs Device Modeling C. Besikci and M. Razeghi IEEE Transactions on Electron Devices 41 (8)-- August 1, 1994 ...[Visit Journal] A reduced set of transport parameters is proposed for the collision terms of the three-valley hydrodynamic model which is a faster alternative to ensemble Monte Carlo simulations. The predictions of the proposed model have been found to be in excellent agreement with transient ensemble Monte Carlo data. The reduction in the number of the transport parameters makes the model relatively easy to implement with substantial accuracy. The transport parameters which are of interest in semiclassical device modeling are presented as a function of electron energy. [reprint (PDF)]
13.	High performance terahertz quantum cascade laser sources based on intracavity difference frequency generation Q.Y. Lu, N. Bandyopadhyay, S. Slivken, Y. Bai and M. Razeghi Optics Express, Vol. 21, No. 1, p. 968-- January 14, 2013 ...[Visit Journal] We demonstrate high power, room temperature, single-mode THz emissions based on intracavity difference frequency generation from mid-infrared quantum cascade lasers. Dual active regions both featuring giant nonlinear susceptibilities are used to enhance the THz power and conversion efficiency. The THz frequency is lithographically tuned by integrated dual-period distributed feedback gratings with different grating periods. Single mode emissions from 3.3 to 4.6 THz with side-mode suppression ratio and output power up to 40 dB and 65 µW are obtained, with a narrow linewidth of 5 GHz. [reprint (PDF)]
13.	Mid-infrared quantum cascade lasers with high wall plug efficiency Y. Bai, B. Gokden, S. Slivken, S.R. Darvish, S.A. Pour, and M. Razeghi SPIE Proceedings, San Jose, CA Volume 7222-0O-- January 26, 2009 ...[Visit Journal] We demonstrate optimization of continuous wave (cw) operation of 4.6 µm quantum cascade lasers (QCLs). A 19.7 µm by 5 mm, double channel processed device exhibits 33% cw WPE at 80 K. Room temperature cw WPE as high as 12.5% is obtained from a 10.6 µm by 4.8 mm device, epilayer-down bonded on a diamond submount. With the semi-insulating regrowth in a buried ridge geometry, 15% WPE is obtained with 2.8 W total output power in cw mode at room temperature. This accomplishment is achieved by systematically decreasing the parasitic voltage drop, reducing the waveguide loss and improving the thermal management. [reprint (PDF)]
13.	Demonstration of mid-infrared type-II InAs/GaSb superlattice photodiodes grown on GaAs substrate B.M. Nguyen, D. Hoffman, E.K. Huang, S. Bogdanov, P.Y. Delaunay, M. Razeghi and M.Z. Tidrow Applied Physics Letters, Vol. 94, No. 22-- June 8, 2009 ...[Visit Journal] We report the growth and characterization of type-II InAs/GaSb superlattice photodiodes grown on a GaAs substrate. Through a low nucleation temperature and a reduced growth rate, a smooth GaSb surface was obtained on the GaAs substrate with clear atomic steps and low roughness morphology. On the top of the GaSb buffer, a p⁺-i-n⁺ type-II InAs/GaSb superlattice photodiode was grown with a designed cutoff wavelength of 4 μm. The detector exhibited a differential resistance at zero bias (R₀A)in excess of 1600 Ω·cm² and a quantum efficiency of 36.4% at 77 K, providing a specific detectivity of 6 X 10¹¹ cm·Hz^½/W and a background limited operating temperature of 100 K with a 300 K background. Uncooled detectors showed similar performance to those grown on GaSb substrates with a carrier lifetime of 110 ns and a detectivity of 6 X 10⁸ cm·Hz^½/W. [reprint (PDF)]
13.	Ridge-Width Dependence on High-Temperature Continuous-Wave Quantum-Cascade Laser Operation S. Slivken, J.S. Yu, A. Evans, L. Doris, J. David, and M. Razeghi IEEE Photonics Technology Letters, 16 (3)-- March 1, 2004 ...[Visit Journal] We report continuous-wave (CW) operation of quantum-cascade lasers (λ=6 μm) up to a temperature of 313 K (40°C). The maximum CW optical output powers range from 212 mW at 288 K to 22 mW at 313 K and are achieved with threshold current densities of 2.21 and 3.11 kA/cm2, respectively, for a high-reflectivity-coated 12-μm-wide and 2-mm-long laser. At room temperature (298 K), the power output is 145 mW at 0.87 A, corresponding to a power conversion efficiency of 1.68%. The maximum CW operating temperature of double-channel ridge waveguide lasers mounted epilayer-up on copper heatsinks is analyzed in terms of the ridge width, which is varied between 12 and 40 μm. A clear trend of improved performance is observed as the ridge narrows. [reprint (PDF)]
13.	ZnO Thin Film Templates for GaN-based Devices D.J. Rogers, F. Hosseini Teherani, A. Yasan, R. McClintock, K. Mayes, S.R. Darvish, P. Kung, M. Razeghi and G. Garry SPIE Conference, Jose, CA, Vol. 5732, pp. 412-- January 22, 2005 ...[Visit Journal] GaN-based optoelectronic devices are plagued by a tendency to non-radiative transitions linked to defects in the active layers. ZnO is promising as a substrate material for GaN because it has the same wurtzite structure and a relatively small lattice mismatch (~1.8%). In this paper, we discuss use of ZnO thin films as templates for GaN based LED. [reprint (PDF)]
13.	Characterization of InTlSb/InSb Grown by Low Pressure Metalorganic Chemical Vapor Deposition on GaAs Substrat Y.H. Choi, P. Staveteig, E. Bigan, and M. Razeghi Journal of Applied Physics 75 (6)-- March 15, 1994 ...[Visit Journal] Optical properties of InTlSb, a new long wavelength infrared material, are investigated. InTlSb/InSb epilayers grown by low‐pressure metal‐organic chemical vapor deposition on semi‐insulating GaAs substrates were characterized using Auger electron spectroscopy and Fourier transform infrared spectroscopy. Auger electron spectra confirm the presence of thallium. Transmission measurements at 77 K indicate an absorption shift from 5.5 μm for InSb up to 8 μm for InTlSb that is confirmed by photoconductivity measurements. [reprint (PDF)]
13.	Broadband, Tunable, and Monolithic Quantum Cascade Lasers M. Razeghi, Q. Y. Lu, N. Bandyopadhyay, W. Zhou, D. Heydari, Y. Bai, and S. Slivken. Semiconductor lasers; (140.3600) Lasers, tunable-- May 19, 2017 ...[Visit Journal] This article describes the state of research and recent developments related to broadband quantum cascade lasers. Monolithic tuning and system development is also discussed. [reprint (PDF)]
13.	High-power laser diodes based on InGaAsP alloys M. Razeghi Nature, Vol.369, p.631-633-- June 23, 1994 ...[Visit Journal] HIGH-POWER, high-coherence solid-state lasers, based on dielectric materials such as ruby or Nd:YAG (yttrium aluminium garnet), have many civilian and military applications. The active media in these lasers are insulating, and must therefore be excited (or ‘pumped’) by optical, rather than electrical, means. Conventional gas-discharge lamps can be used as the pumping source, but semiconductor diode lasers are more efficient, as their wavelength can be tailored to match the absorption properties of the lasing material. Semiconducting AlGaAs alloys are widely used for this purpose, but oxidation of the aluminium and the spreading of defects during device operation limit the lifetime of the diodes3, and hence the reliability of the system as a whole. Aluminium-free InGaAsP compounds, on the other hand, do not have these lifetime-limiting properties. We report here the fabrication of high-power lasers based on InGaAsP (lattice-matched to GaAs substrates), which operate over the same wavelength range as conventional AlGaAs laser diodes and show significantly improved reliability. The other optical and electrical properties of these diodes are either comparable or superior to those of the AlGaAs system. [reprint (PDF)]
13.	Extended electrical tuning of quantum cascade lasers with digital concatenated gratings S. Slivken, N. Bandyopadhyay, Y. Bai, Q. Y. Lu, and M. Razeghi Appl. Phys. Lett. 103, 231110 (2013)-- December 6, 2013 ...[Visit Journal] In this report, the sampled grating distributed feedback laser architecture is modified with digital concatenated gratings to partially compensate for the wavelength dependence of optical gain in a standard high efficiency quantum cascade laser core. This allows equalization of laser threshold over a wide wavelength range and demonstration of wide electrical tuning. With only two control currents, a full tuning range of 500 nm (236 cm⁻¹) has been demonstrated. Emission is single mode, with a side mode suppression of >20 dB. [reprint (PDF)]
13.	Very Long Wavelength Infrared Type-II Detectors Operating at 80K H. Mohseni, A. Tahraoui, J. Wojkowski, M. Razeghi, G.J. Brown, W.C. Mitchel, and Y.S. Park Applied Physics Letters 77 (11)-- September 11, 2000 ...[Visit Journal] We report a demonstration of very long wavelength infrared detectors based on InAs/GaSb superlattices operating at T = 80 K. Detector structures with excellent material quality were grown on an optimized GaSb buffer layer on GaAs semi-insulating substrates. Photoconductive devices with 50% cutoff wavelength of λ_c = 17 μm showed a peak responsivity of about 100 mA/W at T = 80 K. Devices with 50% cutoff wavelengths up to λ_c = 22 μm were demonstrated at this temperature. Good uniformity was obtained over large areas even for the devices with very long cutoff wavelengths. [reprint (PDF)]

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