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  • 1
    Electronic Resource
    Electronic Resource
    Optically pumped laser action and photoluminescence in HgCdTe layer grown on (211) CdTe by metalorganic chemical vapor deposition (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 7102-7107 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photopumped laser action and photoluminescence (PL) in HgCdTe layers grown by metalorganic chemical vapor deposition on (211) oriented CdTe substrates were studied as a function of temperature in the wavelength range 2.5–3.3 μm. Lasing was observed up to 160 K. External quantum efficiency of 5% and single-mirror peak power of 14 mW were measured at 12 K for a 500-μm-long device. The external quantum efficiency was measured for different laser cavity lengths and the results were used to derive the internal efficiency and the laser loss. HgCdTe layers covered with a CdTe cap layer exhibited a lower PL intensity and laser devices with higher threshold.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352378
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  • 2
    Electronic Resource
    Electronic Resource
    Photoluminescence and laser action of Hg1−xCdxTe (x≈0.5) layer grown by liquid-phase epitaxy (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 4260-4269 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence spectra, carrier lifetime, and laser action of Hg1−xCdxTe (x=0.5) layers grown by liquid-phase epitaxy on a CdZnTe substrate were studied as a function of temperature. The minority-carrier lifetime was measured from the recovery of the luminescence signal following pulsed photoexcitation. Photoluminescence spectra of the annealed sample exhibited two lines, 15 meV apart, whereas in an as-grown film one broad line was observed. The transition mechanisms determining the temperature variation of the peak energy and the linewidth are discussed. The luminescence intensity increased rapidly from 300 to 50 K, but leveled off at low temperatures suggesting carrier freezeout in accord with resistivity measurements. Lasing was observed from a cleaved stripe of the wafer using photopumping with a pulsed GaAs laser. The nominal threshold power density increased from 37 W/cm2 μm at 12 K to 380 W/cm2 μm at 130 K, in agreement with threshold calculations. Far-field pattern widths perpendicular and parallel to the film plane of 3.2° and 2.8°, respectively, were measured. Lateral guiding in this device is discussed. The laser wavelength decreased slowly with the photopumping power, suggesting gain pinning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344940
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  • 3
    Electronic Resource
    Electronic Resource
    Optically pumped laser action in double-heterostructure HgCdTe grown by metalorganic chemical vapor deposition on a CdTe substrate (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 15-19 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photopumped laser action in a HgCdTe double-heterostructure grown by metalorganic chemical vapor deposition on a CdTe substrate containing (311)- and (211)-oriented grains was studied. The (311)-oriented device exhibited laser action around λ=4 μm with a threshold power increasing exponentially from 56 mW at T=12 K to 2.8 W at the highest lasing temperature of 90 K. The (211)-oriented laser device emitted around 2.5 μm. The threshold power of the (211) device was much higher than that of the (311) one (1.5 W at 12 K) and increased with temperature at a lower rate to 4.8 W at the highest lasing temperature of 110 K. Front illumination photoluminescence from both active and cladding layers of the (311)-oriented heterostructure was studied as a function of temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354133
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  • 4
    Electronic Resource
    Electronic Resource
    Laser action and photoluminescence in an indium-doped n-type Hg1−xCdxTe (x=0.375) layer grown by liquid phase epitaxy (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 3979-3987 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence, carrier lifetime, and laser oscillation in an indium-doped n-type Hg1−xCdxTe (x=0.375) layer grown by liquid phase epitaxy on CdZnTe were studied. A single-line photoluminescence spectrum was observed up to room temperature. The temperature-dependence of the photoluminescence peak energy and linewidth agrees with a model of band-to-band transitions obeying the k-conservation rule. The carrier lifetime derived from the observed photoluminescence intensity agrees with the observed photodecay lifetime in the temperature range 12–200 K. Laser action was observed in the temperature range 12–90 K at λ=3.6 μm. The laser threshold power increased exponentially with temperature, with a characteristic temperature of 17.5 K. The calculated equivalent threshold current density was found to closely follow the observed one, indicating a maximum threshold gain of 150 cm−1. The calculation shows that at low temperature the threshold power is determined by radiative recombination, while above 50 K Auger recombination becomes dominant. The high value of the threshold gain is attributed to the gain guiding mechanism governing this laser device operation. The observed differential quantum efficiency decreased from 15% at 12 K to 4% at 90 K. A possible mechanism giving rise to this decrease in the efficiency is discussed. The spectrum of the laser with a 3-μm-thick active layer exhibited at high pumping power up to three lines, which were attributed to index guided transverse modes. The 9-μm-thick active layer device exhibited a quasisingle mode spectrum most probably due to gain guiding in both the lateral and the transversal directions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352863
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  • 5
    Electronic Resource
    Electronic Resource
    Photoexcited escape probability, optical gain, and noise in quantum well infrared photodetectors (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4429-4443 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a detailed and thorough study of a wide variety of quantum well infrared photodetectors (QWIPs), which were chosen to have large differences in their optical and transport properties. Both n- and p-doped QWIPs, as well as intersubband transitions based on photoexcitation from bound-to-bound, bound-to-quasicontinuum, and bound-to-continuum quantum well states were investigated. The measurements and theoretical analysis included optical absorption, responsivity, dark current, current noise, optical gain, hot carrier mean free path, net quantum efficiency, quantum well escape probability, quantum well escape time, as well as detectivity. These results allow a better understanding of the optical and transport physics and thus a better optimization of the QWIP performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352210
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  • 6
    Electronic Resource
    Electronic Resource
    Carbon-doped long wavelength GaAs/AlxGa1−xAs quantum well infrared photodetectors grown by organometallic vapor phase epitaxy (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 3642-3644 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report p-doped long wavelength GaAs/AlxGa1−xAs quantum well infrared photodetectors (QWIP) grown by organometallic vapor phase epitaxy. The operation of these devices is based on the photocurrent induced through valence-band intersubband absorption by holes and, unlike n-doped QWIPs, can utilize normal incidence illumination. Carbon was used as the p-type dopant in a low-pressure (30 Torr) vertical-geometry reactor. The C-doped QWIPs consisted of fifty periods of 54-nm-thick undoped AlxGa1−xAs (x=0.36 or 0.30) and C-doped GaAs wells (Lz=4 or 5 nm). Using normal incidence illumination, the C-doped QWIP with shorter wavelength response (x=0.36, Lz=4 nm) exhibited a quantum efficiency of η=21.4% and a detectivity at the peak wavelength of Dλ=5.4×109 cm (square root of)Hz/W at 77 K. The peak and cutoff wavelengths were λp=8.1 μm and λco=8.9 μm, respectively. The C-doped QWIP with longer wavelength response (x=0.30, Lz=5 nm) exhibited a normal incidence η=22.1% and D*λ=3.5×108 cm (square root of)Hz/W for λp=10.5 μm (λco=11.7 μm). The detectivity of the C-doped QWIPs is about four times less than n-doped QWIPs for the same λp but have the advantage of utilizing normal incidence illumination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350899
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  • 7
    Electronic Resource
    Electronic Resource
    19 μm cutoff long-wavelength GaAs/AlxGa1−xAs quantum-well infrared photodetectors (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 5130-5135 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The longest-wavelength quantum-well infrared photodetector ever achieved, with a cutoff wavelength λc=19 μm, is demonstrated. Detailed measurements and an in-depth analysis of the noise, optical gain, detectivity, quantum efficiency, and quantum-well escape probability, are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350618
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  • 8
    Electronic Resource
    Electronic Resource
    Extended long-wavelength λ=11–15-μm GaAs/AlxGa1−xAs quantum-well infrared photodetectors (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 5101-5107 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Success has been achieved in extending the spectral wavelength of GaAs/AlxGa1−xAs quantum-well infrared photodetectors to significantly longer wavelengths, λ=11–15 μm. High responsivity Rp = 0.5 A/W, high quantum efficiency η=12%, and high detectivity D* = 3 × 1010 cm (square root of)Hz/W, as well as an excellent noise equivalent temperature difference NEΔT=4 mK have been achieved at T=50 K. High performance NEΔT=19 mK has also been achieved at an even higher temperature of T=60 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349019
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  • 9
    Electronic Resource
    Electronic Resource
    Photoluminescence study of HgZnTe alloys (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 3592-3597 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence spectra of Hg1−xZnxTe layers with compositions of x=0.226 and 0.248 grown by liquid phase epitaxy on CdZnTe substrates were studied between 12 and 250 K. The annealed x=0.248 sample exhibits two unresolved lines, 15 meV apart, attributed to band-to-band and band to-acceptor transitions. The temperature dependence of the photoluminescence peak energy and of the energy gap, based on infrared transmission measurements, are similar. The linewidth varies with temperature with a slope of 1.6–1.7 kB suggesting transitions obeying the k conservation rule. The measured carrier concentration versus temperature curve reveals a carrier freezeout at low temperatures. The carrier lifetime measured by the photoconductive recovery technique indicates the recombination by the Shockley–Read recombination mechanism. The observed total luminescence intensity exhibits a maximum in this temperature range. The temperature dependence of the quantum efficiency, evaluated from the calculated radiative and the observed total lifetime, was found to agree with that of the total luminescence intensity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.346319
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  • 10
    Electronic Resource
    Electronic Resource
    Efficient frequency doubling and locking of diode laser light in periodically segmented KTiOPO4 waveguide (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2205-2207 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Simultaneous frequency doubling and Bragg reflection locking of the light of a GaAlAs diode laser was obtained by two separate sections of a periodically segmented waveguide of KTiOPO4. A blue light power of 3.6 mW at 429 nm was generated. The blue light was emitted in a circular beam with a low divergence angle of 5.7°. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358802
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