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  • 1
    Electronic Resource
    Electronic Resource
    Temperature dependent photoluminescent properties of InAsxP1−x/InP strained-layer quantum wells (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 3041-3045 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thermal quenching of photoluminescence from InAsxP1−x/InP strained-layer quantum wells has been investigated over the temperature range of 20–295 K. Structures with compositions of x=0.67 and x=1.0 and quantum well thicknesses of 1–17 monolayers were evaluated using Fourier transform photoluminescence spectroscopy. For InAs/InP heterostructures, the activation energy for thermal quenching depended on well thickness. Luminescence quenching was attributed to thermalization of free excitons from the well, and subsequent nonradiative recombination. Addition of phosphorus to the wells alters the recombination process responsible for luminescence quenching.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351514
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  • 2
    Electronic Resource
    Electronic Resource
    Photoluminescence linewidths in metalorganic vapor phase epitaxially grown ordered and disordered InAlGaP alloys (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 5397-5400 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dependence of the photoluminescent properties of In0.48(AlyGa1−y)0.52P alloys (0≤y≤0.5) on growth temperature and substrate misorientation off GaAs(100) has been studied. Samples were grown using low-pressure metalorganic vapor phase epitaxy. By studying the dependence of ordering behavior in InGaP as a function of substrate misorientation and growth temperature simultaneously, a very large range in low-temperature photoluminescence emission energy—135 meV—has been obtained. The photoluminescence linewidth exhibits a strong, continuous dependence on the extent of atomic ordering (the emission energy) in the alloys. The results indicate that inhomogeneity in the microstructure of the material (i.e., between "ordered'' domains and the "disordered'' matrix) is the dominant photoluminescence broadening mechanism. This investigation has allowed a significant optimization of the optical properties of these materials, including the narrowest low-temperature photoluminescent linewidths reported for all of the In(AlyGa1−y)P alloys exhibiting direct band gaps (4.2 meV for InGaP).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352354
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  • 3
    Electronic Resource
    Electronic Resource
    Microstructures of (In,Ga)P alloys grown on GaAs by metalorganic vapor-phase epitaxy (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 3077-3087 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The microstructures of metalorganic vapor-phase epitaxy alloys of (In,Ga)P grown on GaAs substrates were examined using transmission electron microscopy. Alloys examined were grown at 600–775 °C on substrates at or near (001) or (113)A using growth rates of 0.69 and 0.17 nm/s. Two common semiconductor alloy phenomenon, ordering and phase separation, were studied over this range of growth conditions. The CuPt-type ordering reflections are sharpest for growth at 675 °C and more diffuse at 600 and 725 °C due to higher densities of antiphase boundaries. Order can be eliminated by growth at 750 °C or above to obtain the highest band gaps and optical emission energies. Detailed investigation of the microstructure for growth at 675 °C indicates that ordered domains are platelets consisting of thin (1–2 nm) lamella on (001) planes that alternate between the two {111}B ordering variants, in agreement with a model proposed by others. We have formed "unicompositional'' quantum wells with sharply defined ordered layers between disordered barrier layers by changing growth temperature, which demonstrates that ordering is determined to a great degree by the conditions during growth. Phase separation is seen for the entire range of growth parameters, independently of ordering; its contrast shows modulations with a variable spacing ranging from a few nanometers to ∼100 nm. Implications of the coexistence of phase separation and ordering for growth models describing these phenomena are discussed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358659
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  • 4
    Electronic Resource
    Electronic Resource
    Optical properties of InAs/InP strained single quantum wells grown by organometallic vapor-phase epitaxy (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 405-408 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical emission characteristics of highly strained InAs/InP single quantum wells prepared using atmospheric-pressure organometallic vapor-phase epitaxy have been studied. For well thicknesses of one to three monolayers (ML), the photoluminescence (PL) spectra exhibited intense emission in the energy range 1.15–1.3 eV, with typical full width at half maximum of 8–14 meV. The dependence of PL emission energy on well thickness for 1–5-ML-thick wells was compared with the results of a finite-well calculation, taking into account the effects of strain on the band structure. Good agreement between experiment and theory was obtained for a valence-band offset of 270 meV, consistent with recent reports for the InAs/InP system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350289
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  • 5
    Electronic Resource
    Electronic Resource
    Band gap of "completely disordered'' Ga0.52In0.48P (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 3185-3187 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The phenomenon of ordering in Ga0.52In0.48P is well known to reduce the optical band gap; the amount of band gap reduction is often used to measure the degree of ordering. For such measurements to be meaningful, the band gap of the random ("completely disordered'') binary alloy must be known. Values of this fundamental material parameter appearing in the literature vary by up to 40 meV, while the largest band gap reduction reported to date is only about 120 meV, i.e., within a factor of 3 of the uncertainty in one endpoint. We report here a low temperature band gap of 2.010±0.007 eV for material lattice matched to GaAs as deduced from a broad spectrum of samples believed for different reasons to contain minimal ordering. The corresponding value at 295 K is 1.910±0.008 eV. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113717
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  • 6
    Electronic Resource
    Electronic Resource
    Growth and characterization of GaInP unicompositional disorder-order-disorder quantum wells (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 587-589 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Metalorganic vapor phase epitaxy (MOVPE) is used to grow unicompositional quantum-well (QW) structures, in which the QW and barrier layers are composed of ordered and disordered GaInP, respectively. Transmission electron dark-field micrographs reveal abrupt interfaces between highly ordered QWs and disordered barriers, with no evidence of defect formation. Low-temperature photoluminescence from the structures exhibits relatively broad emission peaks, with emission energy increasing with decreasing QW thickness. The dependence of emission energy on well thickness can be described by a finite square well model only when a type-II band alignment is taken for the heterostructure, in which the conduction band edge of the ordered GaInP QW lies about 135–150 meV below that of the disordered barrier material. These results demonstrate a high degree of control over the ordering process in MOVPE, such that quantum size effects can be realized solely through disorder-order phenomena. Further, the data provide strong support for a type-II (spatially indirect) recombination transition between ordered and disordered GaInP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.112307
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  • 7
    Electronic Resource
    Electronic Resource
    Monolayer abruptness in highly strained InAsxP1−x/InP quantum well interfaces (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1142-1144 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: InAsxP1−x/InP strained quantum well structures have been prepared by atmospheric-pressure organometallic vapor phase epitaxy (OMVPE). Structures with compositions of x=0.40–0.67 and quantum well thicknesses of 0.8–16 nm were evaluated using photoluminescence spectroscopy. Strain in the pseudomorphic wells ranged from 1.3 to 2.1%. Doublets and multiplets are observed in the photoluminescence spectra and are attributed to luminescence from regions in the wells differing in thickness by a single monolayer, with atomically smooth interfaces over areas greater in lateral extent than the exciton diameter. Typical full widths at half maximum of the photoluminescence from the thinnest wells are 8–14 meV, comparable to the best reported values for thin lattice-matched quantum wells prepared from the InGaAs(P)/InP system using OMVPE.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100742
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  • 8
    Electronic Resource
    Electronic Resource
    Electric-field-dependent electroreflectance spectra of visible-band-gap (InAlGa)P quantum-well structures (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 1824-1826 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantum-well (MQW) structures. These structures, grown at 775 °C by metalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6° towards P(111〉〈111〉A, consist of nominally undoped MQWs surrounded by doped In0.49Al0.51P cladding layers to form p-i-n diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In0.49Ga0.51P/In0.49(Al0.5Ga0.5)0.51P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg doping profile, confirming the importance of Mg diffusion and unintentional background doping in these materials. Our results show that (InAlGa)P materials are promising for visible-wavelength electro-optic modulator applications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.111767
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  • 9
    Electronic Resource
    Electronic Resource
    Cavity design for improved electrical injection in InAlGaP/AlGaAs visible (639–661 nm) vertical-cavity surface-emitting laser diodes (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 917-919 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A novel optical cavity design for improved electrical injection in visible vertical-cavity surface-emitting laser (VCSEL) diodes employing an InGaP/InAlGaP strained quantum-well active optical cavity and AlAs/Al0.5Ga0.5As distributed Bragg reflectors (DBRs) is described. The cavity design was determined by measuring the lasing threshold current density of visible edge-emitting laser diodes with AlAs/Al0.5Ga0.5As DBR cladding layers. By inserting InAlP spacer layers between the active region and the DBR cladding, significant improvement in the performance of the edge-emitting lasers was achieved. This approach was then applied to the design of visible VCSEL diodes, and resulted in the first demonstration of room-temperature electrically injected lasing, over the wavelength range 639–661 nm. The visible VCSELs, with a diameter of 20 μm, exhibit pulsed output power of 3.4 mW at 650 nm, and continue to lase at a duty cycle of 40%. The threshold current was 30 mA, with a low threshold voltage (2.7 V) and low series resistance (〈15 Ω).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109844
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  • 10
    Electronic Resource
    Electronic Resource
    InAIP/InAlGaP distributed Bragg reflectors for visible vertical cavity surface-emitting lasers (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 2748-2750 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Distributed Bragg reflectors (DBRs) composed of In0.5Al0.5P/In0.5(AlyGa1−y)0.5P quarter-wave layers have been prepared using metalorganic vapor phase epitaxy. The structures were grown over a wide range of high-index layer composition (0≤y≤0.6) and peak reflectivity wavelength (720 nm≤λ≤565 nm, covering the spectrum from deep red to green). In all cases observed and calculated reflectance spectra were in excellent agreement. Using these DBRs, an undoped all-phosphide visible vertical cavity surface-emitting laser structure was grown. Under pulsed optical excitation at room temperature, lasing was obtained at a wavelength of λ∼670 nm, with a threshold power density comparable to that observed from similar structures prepared using AlAs/AlGaAs DBRs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109249
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