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  • 1
    Electronic Resource
    Electronic Resource
    Time and frequency-resolved photoluminescence up conversion using broadly tuneable picosecond infrared pulses (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 1943-1948 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A simultaneous time and frequency-resolved photoluminescence setup based upon the concept of sum-frequency generation has been developed using the parallel collection capabilities of a liquid nitrogen cooled, high quantum efficiency charge coupled device (CCD) detector. This up conversion system can provide excellent time resolution (down to ∼100 fs), when the detector is used in the single channel mode, with large dynamic range. When the CCD detector is used in its full capacity (1024 channels), wide spectral range as well as temporal information are obtained simultaneously from the up-converted signal, thus providing important information on the dynamics of various emission peaks which can occur simultaneously. Together with this, an efficient method for generation of high repetition rate, low energy infrared light between 1.44 and 1.62 μm is described. The technique uses difference frequency mixing of the fundamental wavelength of a mode-locked Nd:yttrium aluminum garnet laser and the output of a synchronously pumped Rhodamine 640 dye laser in a 10 mm long lithium triborate crystal. This source was then used to performed cw and time-resolved up-conversion photoluminescence measurements on a 1.54 μm emitting InGaAsP epitaxial layer. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148877
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  • 2
    Electronic Resource
    Electronic Resource
    Quantum-well intermixing for optoelectronic integration using high energy ion implantation (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 3697-3705 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The technique of ion-induced quantum-well (QW) intermixing using broad area, high energy (2–8 MeV As4+) ion implantation has been studied in a graded-index separate confinement heterostructure InGaAs/GaAs QW laser. This approach offers the prospect of a powerful and relatively simple fabrication technique for integrating optoelectronic devices. Parameters controlling the ion-induced QW intermixing, such as ion doses, fluxes, and energies, post-implantation annealing time, and temperature are investigated and optimized using optical characterization techniques such as photoluminescence, photoluminescence excitation, and absorption spectroscopy. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359948
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  • 3
    Electronic Resource
    Electronic Resource
    Defect diffusion in ion implanted AlGaAs and InP: Consequences for quantum well intermixing (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 2367-2371 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: InGaAs/GaAs/AlGaAs and InGaAs/InGaAsP/InP laser structures, with InGaAs quantum wells approximately 1.85 μm beneath the surface, were implanted with ions having energies up to 8.6 MeV. Intermixing of the quantum wells, after rapid thermal annealing, was monitored through changes in the energy, linewidth, and intensity of the photoluminescence peak from the quantum wells. Where the defects had to diffuse primarily through Al0.71Ga0.29As, these quantities correlate strongly, for short anneal times, with calculated vacancy generation and ion deposition at the depth of the quantum well prior to annealing. This suggests that the defect diffusion length in the AlGaAs and/or GaAs is quite low. For diffusion primarily through InP, the photoluminescence data correlated well with the calculated total number of vacancies created in the sample, suggesting that defect diffusion is very efficient in InP. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360157
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  • 4
    Electronic Resource
    Electronic Resource
    Study of quantum well intermixing caused by grown-in defects (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 3090-3092 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We show that the degree of thermally induced quantum well intermixing is dependent on the growth quality of epitaxial layer structures. Two different undoped quantum well/barrier structures are studied: an InGaAs/InGaAsP 1.5 μm laser-like structure, and an InGaAs/InP structure. In both cases, the temperature of growth of one or more layers is altered and results compared with a control wafer. Wafers with material grown at the lower temperature display blueshifts of up to 80 meV in the QW emission energy during the early stages of rapid thermal annealing. Wafers grown at temperatures that are more standard exhibit excellent stability. We examine shifts of both the heavy hole and light hole transitions as a function of intermixing via transmission measurements, and conclude that interdiffusion occurs primarily on the group V sublattice. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1287406
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  • 5
    Electronic Resource
    Electronic Resource
    Phonons in strained In1−xGaxAs/InP epilayers (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 6423-6428 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Raman spectroscopy has been used to assess the concentration dependence of optical phonons in In1−xGaxAs epilayers grown by chemical beam epitaxy on InP(100). The alloy composition was varied from x=0.325 to x=0.55 to cover the technologically important and physically interesting range where the strain changes sign at x=0.468 from negative to positive. The Raman spectra were curve resolved to reveal the GaAs-like longitudinal optic (LO), disorder induced, InAs-like LO, and InAs-like transverse optic phonons. An examination of the concentration dependence of the phonon frequencies showed that the GaAs-like LO mode varied as ω(cm−1)=252.77+58.643x−50.108x2 for 0.325≤x≤0.55. A comparison of these results with previous infrared and Raman work on In1−xGaxAs has revealed that the concentration dependence of the optical phonon frequencies in the unstrained system is still not accurately known. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1324698
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  • 6
    Electronic Resource
    Electronic Resource
    Enhanced compositional disordering of quantum wells in GaAs/AlGaAs and InGaAs/GaAs using focused Ga+ ion beams (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 621-623 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Spatially selective compositional disordering induced by focused Ga+ ion beam implantation in GaAs/AlGaAs and strained InGaAs/GaAs quantum well structures has been studied using photoluminescence. We find that beyond a certain implantation dosage, the degree of intermixing imparted to a given quantum well saturates and may eventually decline as a result of damage to the semiconductor surface. We overcome this limitation by thermally annealing the sample after implantation to repair the crystalline surface. We show that multiple successive implants interspersed with rapid thermal anneals (RTAs) are successful in locally shifting the optical band gap of quantum wells by many times that attributed to a single implant and RTA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.112983
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  • 7
    Electronic Resource
    Electronic Resource
    New all-optical reflection modulator based on a doubly resonant hetero-nipi saturable Bragg reflection (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 60 (1992), S. 1126-1128 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Very large fractional reflectivity changes (30%) under optical pump densities of ≈3 mW/cm2 are found in a novel GaAs/Al0.35Ga0.65As hetero-nipi structure grown by MBE. This high sensitivity originates in the interaction between the n=1 heavy-hole excitonic resonances in the hetero-nipi and an optical Bragg resonance, designed into the structure through its optical periodicity. The dynamics of the nonlinearity are shown to be dominated by the "giant ambipolar diffusion'' mechanism for in-plane carrier transport, and the implications of this for device applications are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.107454
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  • 8
    Electronic Resource
    Electronic Resource
    Threshold dose for ion-induced intermixing in InGaAs/GaAs quantum wells (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 2412-2414 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have determined the threshold dose for 8 MeV Bi+ ions to induce intermixing of GaAs quantum wells in AlGaAs and InGaAs quantum wells in GaAs after rapid thermal annealing at 850 °C. Our measured threshold for the GaAs/AlGaAs system agrees well with previous work. The threshold for the InGaAs/GaAs system is much lower and explains, at least in part, earlier difficulties in the lateral patterning of nanostructures by focused-ion-beam lithography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.111584
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  • 9
    Electronic Resource
    Electronic Resource
    Band-gap tuning of InGaAs/InGaAsP/InP laser using high energy ion implantation (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 2954-2956 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The technique of ion-induced quantum well intermixing using broad area, high energy (1 MeV P+) ion implantation has been used to tune the emission wavelength of an InGaAs/InGaAsP/InP multiple quantum well (MQW) laser operating at 1.5 μm. The optical quality of the band-gap shifted material is assessed using low-temperature photoluminescence (PL). The band-gap tuned lasers are characterized in terms of threshold current density and external quantum efficiency and exhibit blue shifts in the lasing spectra of up to 63 nm. This approach offers the prospect of a powerful and relatively simple fabrication technique for integrating active as well as passive optoelectronic devices. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114823
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  • 10
    Electronic Resource
    Electronic Resource
    Polarization insensitive InGaAs/InGaAsP/InP amplifiers using quantum well intermixing (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 562-564 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A polarization insensitive optical amplifier based on a lattice matched InGaAs/InGaAsP/InP multiple quantum well (MQW) laser structure operating at 1.5 μm has been fabricated through vacancy enhanced quantum well intermixing using broad area, high energy (1 MeV P+) ion implantation. A simple model shows that if the interdiffusion rate of the anions is larger than that of the cations, the blue shift in the ground state heavy hole transition energy after implantation and annealing is greater than the light hole state blue shift, bringing the two bands together. Current–voltage measurements indicate that junction characteristics are well maintained after implantation. This simple technique for fabricating polarization insensitive optical amplifiers is readily extended to the monolithical integration of such devices along with other passive and active optoelectronic devices and opens the door to practical photonic integrated circuits. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117787
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