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  • 1
    Electronic Resource
    Electronic Resource
    Theoretical performance limits of 2.1–4.1 μm InAs/InGaSb, HgCdTe, and InGaAsSb lasers (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 4552-4559 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Ideal threshold current densities of 2.1–4.1 μm IR lasers are calculated for active layers composed of InAs/InGaSb superlattices, InGaAsSb quantum well quaternaries, InAsSb bulk ternaries, and HgCdTe superlattices. The fully K-dependent band structure and momentum matrix elements, obtained from a superlattice K⋅p calculation, are used to calculate the limiting Auger and radiative recombination rates and the threshold current density. InGaAsSb quantum wells and InAs/InGaSb superlattices are found to be more promising laser candidates than HgCdTe superlattices and InAsSb bulk ternaries. The calculated threshold current densities of InAs/InGaSb superlattices are similar to those of InGaAsSb active layers at 2.1 μm, but are significantly lower at longer wavelengths. Comparison with experiment indicates that the threshold current densities of InGaAsSb-based devices are about three times greater than those calculated for 25 cm−1 gain. The threshold current densities of present InAs/InGaSb superlattices are about 100 times above their theoretical limit. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359798
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  • 2
    Electronic Resource
    Electronic Resource
    Long wavelength InAs/InGaSb infrared detectors: Optimization of carrier lifetimes (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 7143-7152 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The performance characteristics of type-II InAs/InxGa1−xSb superlattices for long and very long-wave infrared detection are discussed. This system promises benefits in this wavelength range over conventional technology based on Hg1−xCdxTe, in part because of suppressed band-to-band Auger recombination rates which lead to improved values of detectivity. The formalism for calculating Auger rates in superlattices is developed and the physical origin of Auger suppression in these systems is discussed. Accurate K⋅p band structures are used to obtain radiative, electron–electron, hole–hole, and band-to-band Auger rules, as well as shallow trap level assisted Auger recombination rates for photodiodes. Theoretical limits for high temperature operation of ideal photovoltaic detectors are presented and compared with HgCdTe. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360422
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  • 3
    Electronic Resource
    Electronic Resource
    Reply to "Comment on ‘Temperature limits on infrared detectivities of InAs/InxGa1−xSb superlattices and bulk Hg1−xCdxTe' '' [J. Appl. Phys. 80, 2542 (1996)] (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 2545-2546 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Despite the preceding Comment's assertions, the maximum theoretical detectivities of LWIR InAs/InGaSb superlattices are greater than those of HgCdTe provided the comparison involves the same base layer thicknesses (greater than the minority carrier diffusion length). The higher optimal doping of the superlattices relative to HgCdTe results in noise suppression. It is desirable because Auger recombination is substantially depressed. Shockley–Van Roosbroeck optical recombination and hence photon recycling is of little consequence in realistic device structures. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363044
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  • 4
    Electronic Resource
    Electronic Resource
    Reply to "Comment on ‘Temperature limits on infrared detectivities of InAs/InxGa1−xSb superlattices and bulk Hg1−xCdxTe' '' [J. Appl. Phys. 74, 4774 (1993)] (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 4156-4158 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Our calculations of the relative performance of ideal superlattice and HgCdTe (MCT) photovoltaic long wave infrared detectors, criticized in the previous Comment, do include radiative lifetimes. They also find the Auger-7 lifetime to be shorter than the radiative lifetime for p doping levels of 1017 cm−3. This agrees with other calculations and with the majority of experiments. The issue of detector thickness raised in the comment is not relevant since neither MCT nor the superlattices has an intrinsic advantage in this respect. The superlattices are further favored relative to MCT by lower tunneling currents, higher uniformity, and materials processing advantages. We suggest the superlattice system to be promising for the eventual realization of high-performance detectors. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359528
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  • 5
    Electronic Resource
    Electronic Resource
    Theoretical performance of InAs/ InxGa1−xSb superlattice-based midwave infrared lasers (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 1940-1942 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We show that for appropriate layer widths the performance of ideal InAs/InxGa1−xSb superlattice-based midwave injection lasers can be limited by radiative rather than Auger recombination. The threshold carrier densities and lifetimes are calculated over the 77–300 K temperature range at 3.5 μm. Lifetimes are obtained from detailed calculations of band-to-band Auger and radiative recombination rates based on realistic nonparabolic band structures. This system is therefore a promising new laser candidate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357682
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  • 6
    Electronic Resource
    Electronic Resource
    Phonon dispersion effects and the thermal conductivity reduction in GaAs/AlAs superlattices (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1498-1503 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The experimentally observed order-of-magnitude reduction in the thermal conductivity along the growth axis of (GaAs)n/(AlAs)n (or n×n) superlattices is investigated theoretically for (2×2), (3×3) and (6×6) structures using an accurate model of the lattice dynamics. The modification of the phonon dispersion relation due to the superlattice geometry leads to flattening of the phonon branches and hence to lower phonon velocities. This effect is shown to account for a factor-of-three reduction in the thermal conductivity with respect to bulk GaAs along the growth direction; the remainder is attributable to a reduction in the phonon lifetime. The dispersion-related reduction is relatively insensitive to temperature (100〈T〈300 K) and n. The phonon lifetime reduction is largest for the 2×2 structures and consistent with greater interface scattering. The thermal conductivity reduction is shown to be appreciably more sensitive to GaAs/AlAs force constant differences than to those associated with molecular masses. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373845
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  • 7
    Electronic Resource
    Electronic Resource
    Thermal conductivity reduction in HgTe/CdTe superlattices (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 2033-2036 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The techniques used previously to calculate the threefold thermal conductivity reduction due to phonon dispersion in GaAs/AlAs superlattices (SLs) are applied to HgTe/CdTe SLs. The reduction factor is approximately the same, indicating that this SL may be applicable both as a photodetector and a thermoelectric cooler. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1432473
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  • 8
    Electronic Resource
    Electronic Resource
    Multilayer thermoelectric refrigeration in Hg1−xCdxTe superlattices (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 3195-3198 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The thermoelectric figure of merit ZT of Hg1−xCdxTe superlattices (SLs) having currents along the growth axis is computed using a realistic SL band structure and the multisubband Boltzmann equation. For a narrow well and wide barrier, a heavy C1 and higher-lying light C2 subband combine to form a (nonoptimal) carrier-energy filter, enhancing the thermopower. The multilayer thermionic emission model accounts for this effect qualitatively but not quantitatively. However, for a narrow well and narrow-barrier system, ZT is 20% larger than that in the wide-barrier structure, indicating that devices based on carrier-energy filter/thermionic processes are not necessarily advantageous. ZT is almost three times larger than that in Bi2Te3 and is four times larger than that in an alloy with the average composition of the SL. This effect is associated with reduced lattice thermal conductivity in the SL rather than improved electronic transport. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371188
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  • 9
    Electronic Resource
    Electronic Resource
    Induced electric fields in anisotropic thermoelectric materials (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 5065-5069 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Transport in an anisotropic material can create potentially large induced transverse fields which reduce the measured electric and thermal conductivities relative to those computed without the induced fields. These affect the thermoelectric figure of merit ZT modestly. The induced electric field in n-type Bi2Te3 is predicted to be as much as 76% of the external one and can lower the measured electrical conductivity by up to 60%. In Hg1−xCdxTe superlattices, the anisotropy may be increased by varying the composition and width of the barrier and well to give induced fields much larger than the applied one. These effects should be easily observable. The present work utilizes general results applied to a microscopic model relevant for multivalleyed materials within the effective-mass and relaxation-time approximations. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371480
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  • 10
    Electronic Resource
    Electronic Resource
    Temperature limits on infrared detectivities of InAs/InxGa1−xSb superlattices and bulk HgxCd1−xTe (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 4774-4776 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Detailed theoretical calculations of Auger and radiative recombination rates for an optimized InAs/InxGa1−xSb superlattice (SL) and bulk HgxCd1−xTe (MCT) show that 300 K background limited operation for a 60° field of view can be theoretically achieved up to 130 K for the 11 μm SL and up to 185 K for 5 μm MCT. The SL structure is theoretically superior to MCT for 11 μm operation. The converse is true at 5 μm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354348
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