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  1. Sb-induced strain fluctuations in a strained layer superlattice of InAs/InAsSb

    Here, we show that Sb substitution for As in a MBE grown InAs/InAsSb strained layer superlattice (SLS) is accompanied by significant strain fluctuations. The SLS was observed using scanning transmission electron microscopy along the [100] zone axis where the cation and anion atomic columns are separately resolved. Strain analysis based on atomic column positions reveals asymmetrical transitions in the strain profile across the SLS interfaces. The averaged strain profile is quantitatively fitted to the segregation model, which yields a distribution of Sb in agreement with our scanning tunneling microscopy result. The subtraction of the calculated strain reveals an increase inmore » strain fluctuations with the Sb concentration, as well as isolated regions with large strain deviations extending spatially over ~1 nm, which suggest the presence of point defects.« less
  2. An InGaSb p-channel FinFET.

    Abstract not provided.
  3. Analysis of MWIR nBn Devices Built with III-V Superlattices for Strategic Applications on STAMPEDE.

    Abstract not provided.
  4. Next-Generation Infrared Focal Plane Arrays for High-Efficiency Low-Noise Applications.

    Abstract not provided.
  5. Next-Generation Infrared Focal Plane Arrays for High-Responsivity Low-Noise Applications.

    Abstract not provided.
  6. Evidence for an Excitonic Insulator Phase in a Zero-Gap InAs/GaSb Bilayer.

    Abstract not provided.
  7. Low Dimensional Plasmonic Spectroscopy through Inversion of the Far Infrared Detection Problem.

    Abstract not provided.
  8. Raman Scattering Study of Lattice Vibrations in the Type-II Superlattice InAs / InAs 1 - x Sb x

    The InAs/InAs 1-xSb x superlattice system distinctly differs from two well-studied superlattice systems GaAs / AlAs and InAs/GaSb in terms of electronic band alignment, common elements at the interface, and phonon spectrum overlapping of the constituents. This fact leads to the unique electronic and vibrational properties of the InAs/InAs 1-xSb x system when compared to the other two systems. Here, we report a polarized Raman study of the vibrational properties of the InAs/InAs 1-xSb x superlattices (SLs) as well as selected InAs 1-xSb x alloys, all grown on GaSb substrates by either MBE or metalorganic chemical vapor deposition (MOCVD) frommore » both the growth surface and cleaved edge. In the SL, from the (001) backscattering geometry, an InAs-like longitudinal optical (LO) mode is observed as the primary feature, and its intensity is found to increase with increasing Sb composition. From the (110) cleaved-edge backscattering geometry, an InAs-like transverse optical (TO) mode is observed as the main feature in two cross-polarization configurations, but an additional InAs-like “forbidden” LO mode is observed in two parallel-polarization configurations. The InAs 1-xSb x alloys lattice matched to the substrate (x Sb ~ 0.09) grown by MBE are also found to exhibit the forbidden LO mode, implying the existence of some unexpected [001] modulation. However, the strained samples (x Sb ~ 0.35) grown by MOCVD are found to behave like a disordered alloy. The primary conclusions are (1) the InAs-like LO or TO mode can be either a confined or quasiconfined mode in the InAs layers of the SL or extended mode of the whole structure depending on the Sb composition. (2) InAs/InAs 1-xSb x and InAs/GaSb SLs exhibit significantly different behaviors in the cleaved-edge geometry but qualitatively similar in the (001) geometry. (3) The appearance of the forbidden LO-like mode is a universal signature for SLs and bulk systems resulting from the mixing of phonon modes due to structural modulation or symmetry reduction.« less
  9. Temperature dependent carrier lifetimes of InAs/InAsSb type-2 superlattices.

    Abstract not provided.
  10. Intensity and temperature dependent carrier recombination in InAs/InAsSb type-II superlattices.

    Abstract not provided.

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"Hawkins, Samuel D."

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