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  • 1
    Electronic Resource
    Electronic Resource
    Effects of interdiffusion on the sub-band-edge structure of In0.53Ga0.47As/InP single quantum wells (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 73 (1993), S. 7524-7532 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The disordering of In0.53Ga0.47As/InP single quantum wells has been studied using an error function distribution to model the compositional profile after interdiffusion. When considering interdiffusion on the group-III sublattice only, a large strain buildup results during the early stages of disordering. Details are presented showing how this interdiffusion and the effects of strain lead to an interesting carrier confinement profile which differs from that of disordered AlGaAs/GaAs and InGaAs/GaAs quantum-well structures. An abrupt confinement profile is maintained even after significant interdiffusion, with a well width equal to that of the as-grown quantum well. The combined effects of strain with the unstrained band-gap profile results in a potential buildup in the barrier near the interface, while it gives rise to two "miniwells'' inside the potential wells. The sub-band-edge structure shows that the potential buildup can result in quasibound subband states, while the heavy-hole well can support the ground state within the miniwells. In contrast, when identical interdiffusion on both group-III and group-V sublattices is considered, the structure remains lattice matched, the confinement profile changes to that of a graded profile, and the ground-state transition energy shifts to shorter wavelengths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354095
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  • 2
    Electronic Resource
    Electronic Resource
    The optical properties of AlGaAs/GaAs hyperbolic quantum-well structures (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 1054-1056 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical properties of a nonsquare quantum well with a hyperbolic potential profile have been analyzed. The quantized energy levels for the confined carriers are determined analytically using the effective mass approximation. The absorption coefficients for an undoped AlGaAs/GaAs hyperbolic quantum-well structure have been calculated based on the one electron density matrix formulation, taking into account broadening effect due to intraband relaxation by carrier–carrier scattering. The results show that the absorption edge as well as its peak value are more sensitive to well shape than well width.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349694
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  • 3
    Electronic Resource
    Electronic Resource
    Erratum: "Modeling the optical constants of HgxCd1−xTe alloys in the 1.5–6.0 eV range" [J. Appl. Phys. 85, 2854 (1999)] (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 4713-4713 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371526
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  • 4
    Electronic Resource
    Electronic Resource
    Vacancy-enhanced intermixing in highly strained InGaAs/GaAs multiple quantum well photodetector (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 3402-3407 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Impurity-free vacancy disordering techniques using rapid thermal annealing with electron-beam evaporated SiO2 encapsulant was utilized to study its effect on the optical and electrical properties of the highly strained InGaAs/GaAs quantum well infrared photodetector. The photoluminescence peak is blueshifted and its line width does not increase much, indicating the compositional disordering of the quantum well structure and there is no strain relaxation or minimal deterioration of the heterostructure quality. Both transverse electric and transverse magnetic infrared intersubband transitions are retained and observed after intermixing. The absorption peak wavelength is redshifted from the as grown 10.2 μm to the interdiffused 10.5 and 11.2 μm, for 5 and 10 s annealing at 850 °C, respectively, without appreciable degradation in absorption strength. Theoretical calculations of the absorption spectra are in good agreement with the experimental data. Annealed responsivity spectra of both 0° and 90° polarization are of comparable amplitude but with narrower spectra line width. Dark current of the annealed devices is found to be an order of magnitude larger than the as-grown one at 77 K. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371220
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  • 5
    Electronic Resource
    Electronic Resource
    Modeling the optical properties of hexagonal GaN (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 73 (1998), S. 868-870 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An adjustable broadening function instead of the conventional Lorentzian one is incorporated in the dielectric function model for hexagonal GaN. One-electron contributions at E1 critical points and higher-state (m〉1) exciton terms, which were incorrectly disregarded in the previous study, are taken into account. Model parameters were determined using the acceptance-probability-controlled simulated annealing. As a result, excellent agreement with experimental data for both real and imaginary parts in the range from 1.5 to 10 eV is obtained. Average discrepancy between experimental and calculated data for the real part of the index of refraction equals 2.75×10−4, and for the imaginary part is 1.66×10−3. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121970
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  • 6
    Electronic Resource
    Electronic Resource
    Refractive index of InGaN/GaN quantum well (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 6312-6317 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this article, the optical properties of the InxGa1−xN/GaN quantum well (QW) are investigated. The refractive index spectrum of a QW is essential to the design and implementation of optoelectronic devices. Yet, the refractive index of the InGaN/GaN QW system over a wide spectral range has been unavailable so far. This article presents a comprehensive model, which includes the exciton effect and most of the major critical points, to calculate the complex index of refraction of the InGaN/GaN QW at room temperature. The calculations have been performed for QW's with various alloy compositions and well widths in the spectral range from 1 to 9 eV. The model presented here fully considers transitions near the band edge and above barrier gap contributions. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368954
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  • 7
    Electronic Resource
    Electronic Resource
    Electro-absorptive properties of interdiffused InGaAsP/InP quantum wells (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 3861-3869 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of Group III and Group V interdiffusions with a varied as-grown well width and P concentration in the quaternary InGaAsP quantum well material have been theoretically studied. Interesting features of multiple mini-well profiles, generated by interdiffusion induced compressive and tensile strains, have been obtained and varying envelope overlapping of the electron-hole wave functions has been observed. The results show that the interdiffusion of the Group III elements with a well width of 10 nm offers a wide adjustability of the operation wavelength, enhances Stark shift, and reduces absorption loss, although they bear the shortcomings of low electro-absorption and contrast ratio. Several methods are proposed here to recover the contrast ratio with a maximum improvement of 66%. For the Group V interdiffusion of a 10-nm-wide as-grown well, a low absorption loss and a large Stark shift will result, while that of a narrowed well can widen the band-edge wavelength adjustability with a large electro-absorption. These results are important for the development of electro-absorptive InGaAsP/InP diffused quantum well modulators. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365752
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  • 8
    Electronic Resource
    Electronic Resource
    Refractive index of interdiffused AlGaAs/GaAs quantum well (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 6251-6258 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A model is developed for the polarization dependent refractive index of interdiffused AlGaAs/GaAs quantum well at room temperature for wavelengths ranging from 0.6 to 2 μm. The present model is based on a semianalytic and semiempirical method through the Kramers–Krönig transformation. The multi-quantum-well structures, including the exciton effect and above barrier gap contributions, are fully considered in this model. The distinct structures at energies of the E0,E0+Δ0,E1, and E2 critical points are revealed. Moreover, the birefringence at room temperature is also analyzed in the wavelength range varying from 0.7 to 1.0 μm. The calculated refractive index results are in satisfactory agreement with the experimental measurements over the quantum well band edge, i.e., 0.8–0.9 μm. The effect of interdiffusion on the change of refractive index is discussed. The polarization dependent absorption coefficients are also calculated with all the bound excitons, and results agree well with experiments. These results are important, since refraction index in a particular wavelength region of interest, where experimental data are not available, can be determined and thus are very useful in the design of devices. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366512
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  • 9
    Electronic Resource
    Electronic Resource
    Dielectric function models for describing the optical properties of hexagonal GaN (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 273-282 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Several different models have been employed for modeling the dielectric function of hexagonal GaN in the range from 1 to 10 eV. Models are compared in terms of number of parameters required, intricacy of model equations, and possibility of accurate estimation of important physical parameters, such as energies of critical points and exciton binding energies. Shortcomings and advantages of each model are discussed in detail. Excellent agreement with the experimental data for GaN has been achieved with three of the investigated models. It has also been shown that an assumption of adjustable broadening instead of a purely Lorentzian one improves the agreement with the experimental data and enables elimination of excessive absorption below the gap which is inherent to the models with Lorentzian broadening. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1331069
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of interdiffusion on the polarization dependent refractive index of a strained InGaAs/GaAs quantum well (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 3164-3166 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The polarization dependent refractive index of disordered, strained InGaAs/GaAs single quantum wells is calculated using the complex dielectric function, taking into consideration the contributions from the Γ, X, and L Brillouin zones. At longer wavelengths the refractive index decreases as the extent of disordering increases, resulting in a positive refractive index step when the lateral confining regions are more extensively disordered. The structure also exhibits birefringence in the quantum well band edge to barrier band-edge wavelength range which decreases with interdiffusion. The refractive index is polarization independent outside this wavelength range. Interdiffusion extends this zero birefringence to shorter wavelengths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109116
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