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L. E. Vorobjev,
M. Ya. Vinnichenko,
D. A. Firsov,
V. L. Zerova,
V. Yu. Panevin,
A. N. Sofronov,
P. Thumrongsilapa,
V. M. Ustinov,
A. E. Zhukov,
A. P. Vasiljev,
L. Shterengas,
G. Kipshidze,
T. Hosoda, G. Belenky
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ABSTRACT: Carrier heating in GaAs/AlGaAs quantum wells (QWs) under optical interband pumping in the spontaneous-emission mode has been
studied. The electron temperature was determined as a function of the pumping intensity. The effect of the electric field
on the photoluminescence spectrum was examined. The change in the carrier concentration with the drive current in the spontaneous-
and stimulated-emission modes in InGaAsSb/InAlGaAsSb QWs was determined from electroluminescence spectra. The rise in the
temperature of hot carriers, which results in the increase in the carrier concentration with the drive current, was roughly
estimated.
Semiconductors 05/2012; 44(11):1402-1405. · 0.63 Impact Factor
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Journal of Applied Physics 08/2011; 110:043720. · 2.17 Impact Factor
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ABSTRACT: High-power 2.2-μm diode lasers and their arrays were designed and fabricated. Laser heterostructures were grown using solid-source molecular beam epitaxy on GaSb substrates. The device active regions contained two 1.5% compressively strained GaInAsSb quantum wells. Heavy compressive strain in the active region ensured strong carrier confinement and high differential gain. A broadened waveguide design approach was utilized to obtain an internal optical loss below 4 cm<sup>-1</sup> and a threshold current density below 100 A/cm<sup>2</sup>. Individual high-power lasers produced 1.6 W of continuous-wave (CW) multimode power at room temperature from a single 100-μm-wide aperture. Linear laser arrays generated more than 25 W of quasi-continuous wave output power. The device power conversion efficiencies were better than 20% in peak and above 10% at maximum output power level.
IEEE Photonics Technology Letters 06/2011; · 2.19 Impact Factor
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ABSTRACT: GaSb-based type I InGaAsSb quantum well mid-infrared (mid-IR) light-emitting diodes (LEDs) operated at wavelengths up to 3.66 µm are demonstrated. The application of quinternary AlGaInAsSb barriers improved hole confinement in the quantum wells and enabled an LED radiant excitance of 1.3 W cm−2 (λ = 3.66 µm) at 100 K which corresponds to the emittance of a blackbody at 1350 K. High-contrast individually addressed 512 × 512 LED arrays were designed and fabricated using wet etching. An accurate characterization technique for mid-IR LEDs has been developed.
Semiconductor Science and Technology 05/2011; 26(8):085022. · 1.72 Impact Factor
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ABSTRACT: Metamorphic virtual substrates with lattice constants 0.9% larger than those of GaSb were developed by solid-source molecular beam epitaxy. The mismatch between the parent GaSb and the virtual substrate was accommodated by a network of misfit dislocations formed in GaInSb buffer layers with linearly graded indium and gallium compositions. Arsenic-free laser heterostructures emitting at 2.2 μm at room temperature were grown on virtual substrates. The antimony was the only group V element used in growth. These novel diode lasers operate at room temperature and generate above 1.4 W of continuous-wave (CW) power.
IEEE Photonics Technology Letters 04/2011; · 2.19 Impact Factor
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ABSTRACT: A continuous-wave, room temperature operation of type-I quantum well diode lasers was extended above 3.4 μm. The laser heterostructure, optimised for minimum threshold carrier concentration, was pseudomorphically grown by solid source molecular beam epitaxy on GaSb. Multimode lasers generate 29 mW of output power at 17°C.
Electronics Letters 11/2010; · 0.96 Impact Factor
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ABSTRACT: Type-I quantum-well (QW) diode lasers based on AlInGaAsSb-InGaAsSb-AlInGaAsSb heterostructure active region with narrow waveguide and high indium content in the barrier were fabricated. Room-temperature continuous-wave output power of 190, 165, and 50 mW for devices emitting 3.1, 3.2, and 3.3 μm correspondingly were demonstrated. Experiment shows that improvement of the hole confinement in QWs by use of 32% indium in AlGaInAsSb barrier is a promising way of further enhancement of the device performance.
IEEE Photonics Technology Letters 06/2010; · 2.19 Impact Factor
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ABSTRACT: Ridge waveguide type-I quantum-well GaSb-based diode lasers operating at room temperatures in the spectral region near 3.15 m have been designed and fabricated. The laser active region comprises three InGaAsSb quantum-wells embedded into quinary AlInGaAsSb barrier material to promote carrier confinement. Lasers generate 9 mW of continuous-wave output power at 3.16 m in a diffraction limited beam at 20°C. Devices operate in continuous-wave regime up to 40°C producing above 1 mW of power at wavelength above 3.2 m.
Electronics Letters 04/2010; · 0.96 Impact Factor
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ABSTRACT: GaSb-based diode lasers with type-I quantum-well active region located either in the center of quinary AlInGaAsSb broadened waveguide or shifted to the p-cladding side were fabricated and characterized. Devices with narrower 'p-side waveguide' demonstrate better performance. We explain the phenomenon by reduced hole concentration in the waveguide region of the device. At 12 °C, lasers with optimized design generate above 65 mW of continuous wave output power at 3.2 µm.
Semiconductor Science and Technology 10/2009; 24(11):115013. · 1.72 Impact Factor
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ABSTRACT: Type-I double-quantum-well GaSb-based diode lasers operating at 3 mum with room-temperature continuous-wave output power above 300 mW and peak power-conversion efficiency near 8 were designed and fabricated. Laser heterostructure comprised quinary AlGaInAsSb alloy as barrier and waveguide material. Use of quinary alloy resulted in adequate hole confinement. The waveguide thickness was chosen to maximise modal differential gain. Continuous-wave threshold current density about 100 A/cm<sup>2</sup> per quantum-well and slope efficiency of 100 mW/A were demonstrated at 17degC.
Electronics Letters 09/2009; · 0.96 Impact Factor
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ABSTRACT: A stable 3-microm-wavelength, GaSb-based diode operated at room temperature has been investigated as a potential laser source for cryogenic target layering at the Omega Laser Facility for inertial confinement fusion (ICF) experiments. More than 50 mW of output power has been achieved at 14 degrees C with high spectral and output-power stability.
Optics Express 09/2009; 17(18):15760-5. · 3.59 Impact Factor
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ABSTRACT: Type I GaSb-based light-emitting diodes (LEDs) have been demonstrated while operating at room temperature at wavelengths up to 3.66 mum with approximately 200 muW of quasi- continuous-wave optical power. A mid-infrared 6 times 6 addressable array of Type I LEDs was also demonstrated.
IEEE Photonics Technology Letters 09/2009; · 2.19 Impact Factor
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ABSTRACT: Type-I double-quantum-well (QW) GaSb-based diode lasers operating at 2.7 mum with room-temperature continuous-wave (CW) output power of 600 mW and peak power-conversion efficiency of 10% were designed and fabricated. The devices employed 470-nm-wide AlGaInAsSb waveguide optimized for improved device differential gain. CW threshold current density about 100 A/cm<sup>2</sup> per QW and slope efficiency of 150 mW/A were demonstrated at 16degC.
IEEE Photonics Technology Letters 09/2009; · 2.19 Impact Factor
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ABSTRACT: Dilute-nitride GaNSb bulk materials with up to 1.4% nitrogen were grown by molecular beam epitaxy on GaSb substrates. Hall measurements indicate residual hole concentrations of nearly 10<sup>19</sup> cm <sup>-3</sup> at room temperature, but a decrease to below 10<sup>16</sup> cm <sup>-3</sup> and a hole mobility of 1300 cm <sup>2</sup>/ V s at 4.5 K for a sample with 0.6% nitrogen. Photoluminescence (PL) and optical absorption measurements demonstrate a bandgap reduction by up to 300 meV with increasing nitrogen incorporation. The experimental absorption spectra are well fit by a functional dependence corresponding to direct allowed optical transitions, and the PL spectra are also consistent with that interpretation. Room temperature carrier relaxation times in the picosecond range are measured using an ultrafast PL upconversion technique.
Journal of Applied Physics 02/2009; · 2.17 Impact Factor
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ABSTRACT: InGaAsSb/AlGaAsSb quantum well (QW) diode laser structures with either 1% or 1.5% compressively strained QWs were grown on GaSb substrates by molecular beam epitaxy. Wide-stripe lasers fabricated from structures of both types have room-temperature operating wavelengths near 2.3 microns. The room-temperature threshold current density of 1-mm-long uncoated devices with 1.5% strained QWs was lower than threshold current density of the 1.0% strained QW devices by nearly a factor of two (120 A/cm<sup>2</sup> versus 230 A/cm<sup>2</sup> ). Experiment shows that the reduction in threshold current density with increasing QW strain is related to the increase in differential gain and decrease in transparency current density. Optical gain calculations prove that improvement of the QW hole confinement reduces the threshold carrier concentration in laser structures with heavily strained low arsenic content quantum wells.
IEEE Journal of Quantum Electronics 01/2009; · 1.88 Impact Factor
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ABSTRACT: GaSb-based type-I quantum-well diode lasers emitting at 3.36 μm at 12 °C with 15 mW of continuous wave output power are reported. Devices with two or four InGaAsSb compressively strained quantum wells and AlInGaAsSb quinternary barriers were fabricated and characterized. It was shown that increase in the quantum-well number led to improved laser differential gain and reduced threshold current.
Applied Physics Letters 07/2008; 93(1):011103-011103-3. · 3.84 Impact Factor
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ABSTRACT: A segmented contact method for the measurement of optical gain is developed for the case of strong current spreading. A simple model of current spreading in a ridge laser with a segmented contact is proposed and analyzed. We show that current spreading effects should be taken into account in lasers with low threshold current densities and high ldquoopeningrdquo voltages. When applied to interband cascade lasers, the method gives an internal optical loss of ~ 10-17 cm<sup>-1</sup> and a differential gain of ~ 2.9 cm/A at 80 K, which agrees well with previously reported Hakki-Paoli data. The limitations of the technique are discussed.
IEEE Journal of Quantum Electronics 07/2008; · 1.88 Impact Factor
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ABSTRACT: High-power diode lasers with heavily strained In(Al)GaAsSb type-I quantum-well active regions emitting at 3.1 μm at room temperature are reported. The devices produce continuous-wave output powers above 200 mW at 250 K and 80 mW at 285 K.
Applied Physics Letters 04/2008; 92(17):171111-171111-3. · 3.84 Impact Factor
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ABSTRACT: Experimental studies of the electron and hole concentration dynamics in the barrier of GaSb-based type-II quantum-well (QW) heterostructures were performed. Capture of electrons and holes was studied separately in specially designed and grown laser heterostructures with QWs only for electrons or only for holes. The difference between electron and hole relaxation rates is explained by corresponding QW carrier confinement energies.
Applied Physics Letters 09/2007; 91(10):101106-101106-3. · 3.84 Impact Factor
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ABSTRACT: Carrier lifetime of 2 ns was measured in GaSb-based type-I quantum-well high power laser heterostructures at threshold carrier concentration. Increased carrier capture rate was observed in laser heterostructures with reduced waveguide thickness.
Lasers and Electro-Optics, 2007. CLEO 2007. Conference on; 06/2007
