Electron-hole interactions in coupled InAs-GaSb quantum dots based on nanowire crystal phase templates

Nilsson, Magnus; Namazi, Luna; Lehmann, Sebastian; Leijnse, Martin; Dick, Kimberly A.; Thelander, Claes

doi:10.1103/physrevb.94.115313

Cited by 19 publications

(22 citation statements)

References 28 publications

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“…In order to investigate the electrical characteristics, nanowires both with and without the outer InAs shell were transferred to measurement substrate where metal contacts were fabricated in a similar manner as described in ref. . Here, the substrate is used as a global back gate and the distance between source and drain contacts are 800 nm.…”

Section: Methodsmentioning

confidence: 99%

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Realization of Wurtzite GaSb Using InAs Nanowire Templates

Namazi

Gren

Nilsson

et al. 2018

Adv Funct Materials

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The crystal structure of a material has a large impact on the electronic and material properties such as band alignment, bandgap energy, and surface energies. Au-seeded III-V nanowires are promising structures for exploring these effects, since for most III-V materials they readily grow in either wurtzite or zinc blende crystal structure. In III-Sb nanowires however, wurtzite crystal structure growth has proven difficult. Therefore, other methods must be developed to achieve wurtzite antimonides. For GaSb, theoretical predictions of the band structure diverge significantly, but the absence of wurtzite GaSb material has prevented any experimental verification of the properties. Having access to this material is a critical step toward clearing the uncertainty in the electronic properties, improving the theoretical band structure models and potentially opening doors toward application of this material. This work demonstrates the use of InAs wurtzite nano wires as templates for realizing GaSb wurtzite shell layers with varying thicknesses. The properties of the axial and radial heterointerfaces are studied at the atomic scale by means of aberration-corrected scanning transmission electron microscopy, revealing their sharpness and structural quality. The transport characterizations point toward a positive offset in the valence band edge of wurtzite compared to zinc blende.

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Section: Methodsmentioning

confidence: 99%

“…The InAs–GaSb heterostructure system is particularly suitable for various tunneling‐based device applications such as tunneling field effect transistors (TFETs) and diodes due to the broken bandgap alignment it exhibits . This material combination has been previously investigated in detail in the axial and radial configurations …”

Section: Introductionmentioning

confidence: 99%

Realization of Wurtzite GaSb Using InAs Nanowire Templates

Namazi

Gren

Nilsson

et al. 2018

Adv Funct Materials

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“…In addition to the QWs, InAs/GaSb core-shell nanowires (NWs) have been investigated both experimentally and theoretically. [5][6][7][8][9][10][11][12][13][14][15] Core-shell NWs with one shell are grown by several groups today, [8][9][10][11][12][13][14][15][16] and NWs with two shells can be grown, 16 e.g., for the reason of a passivating outer layer on InAs. 14 In this work we study core-shell-shell NWs, where an insulator core is radially overgrown with one InAs and one GaSb layer, see Fig.…”

Section: Introductionmentioning

confidence: 99%

Band structure and end states in InAs/GaSb core-shell-shell nanowires

et al. 2020

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Quantum wells in InAs/GaSb heterostructures can be tuned to a topological regime associated with the quantum spin Hall effect, which arises due to an inverted band gap and hybridized electron and hole states. Here, we investigate electron-hole hybridization and the fate of the quantum spin Hall effect in a quasi one-dimensional geometry, realized in a core-shell-shell nanowire with an insulator core and InAs and GaSb shells. We calculate the band structure for an infinitely long nanowire using k • p theory within the Kane model and the envelope function approximation, then map the result onto a BHZ model which is used to investigate finite-length wires. Clearly, quantum spin Hall edge states cannot appear in the core-shell-shell nanowires which lack onedimensional edges, but in the inverted band-gap regime we find that the finite-length wires instead host localized states at the wire ends. These end states are not topologically protected, they are four-fold degenerate and split into two Kramers pairs in the presence of potential disorder along the axial direction. However, there is some remnant of the topological protection of the quantum spin Hall edge states in the sense that the end states are fully robust to (time-reversal preserving) angular disorder, as long as the bulk band gap is not closed.

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“…Significant progress has been made in the synthesis and bandstructure engineering of III-V semiconductors. For example, quantum dots (QDs) can be embedded into radial [11,12] and axial [13,14,15] NW heterostructures, directly grown complex multiple NW geometries such as crosses [16,17,18] or networks [19] have become feasible, as well as in situ grown expitaxial superconducting shells [20] for superconducting hybrid devices [21,22].…”

Section: Introductionmentioning

confidence: 99%

Highly symmetric and tunable tunnel couplings in InAs/InP nanowire heterostructure quantum dots

Thomas,

Baumgartner,

Gubser

et al. 2019

Preprint

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We present a comprehensive electrical characterization of an InAs/InP nanowire heterostructure, comprising two InP barriers forming a quantum dot (QD), two adjacent lead segments (LSs) and two metallic contacts, and demonstrate how to extract valuable quantitative information of the QD. The QD shows very regular Coulomb blockade (CB) resonances over a large gate voltage range. By analyzing the resonance line shapes, we map the evolution of the tunnel couplings from the few to the many electron regime, with electrically tunable tunnel couplings from <1 µeV to >600 µeV, and a transition from the temperature to the lifetime broadened regime. The InP segments form tunnel barriers with almost fully symmetric tunnel couplings and a barrier height of ∼ 350 meV. All of these findings can be understood in great detail based on the deterministic material composition and geometry. Our results demonstrate that integrated InAs/InP QDs provide a promising platform for electron tunneling spectroscopy in InAs nanowires, which can readily be contacted by a variety of superconducting materials to investigate subgap states in proximitized NW regions, or be used to characterize thermoelectric nanoscale devices in the quantum regime.

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Electron-hole interactions in coupled InAs-GaSb quantum dots based on nanowire crystal phase templates

Cited by 19 publications

References 28 publications

Realization of Wurtzite GaSb Using InAs Nanowire Templates

Realization of Wurtzite GaSb Using InAs Nanowire Templates

Band structure and end states in InAs/GaSb core-shell-shell nanowires

Highly symmetric and tunable tunnel couplings in InAs/InP nanowire heterostructure quantum dots

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