Epitaxial type-I and type-II InAs-AlAsSb core–shell nanowires on silicon

Giudice, Fabio; Fust, Sergej; Schmiedeke, Paul; Pantle, Johannes; Döblinger, Markus; Ajay, Akhil; Meder, Steffen; Riedl, Hubert; Finley, Jonathan J.; Koblmüller, Gregor

doi:10.1063/5.0065867

Cited by 7 publications

(14 citation statements)

References 49 publications

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“…25,26 Passivated NWs under the respective AlAs 0.18 Sb 0.82 shell composition suggest a type-I band alignment at the core−shell interface, as inferred from recent μ-PL measurements. 26 As a first way to describe the presence of hot-carrier effects in these NWs, we illustrate excitation energy-and power-dependent μ-PL experiments performed on a passivated core−shell NW at room temperature. Details about the μ-PL setup are described in Section S3 of the Supporting Information and elsewhere.…”

Section: Experimental Methods and Resultssupporting

confidence: 55%

“…26 The respective NWs exhibit a wurtzite-dominated crystal phase and a high density of stacking faults, as defined by the NW core. 25,26 Passivated NWs under the respective AlAs 0.18 Sb 0.82 shell composition suggest a type-I band alignment at the core−shell interface, as inferred from recent μ-PL measurements. 26 As a first way to describe the presence of hot-carrier effects in these NWs, we illustrate excitation energy-and power-dependent μ-PL experiments performed on a passivated core−shell NW at room temperature.…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%

“…Details about the μ-PL setup are described in Section S3 of the Supporting Information and elsewhere. 26 In general, the PL of NWs allows for the characterization of photoexcited charge carriers in equilibrium. Hereby, the carrier temperature (T C ) is commonly extracted by a full fit of the following function with the absorption function α(ℏω) and the T C .…”

Section: Experimental Methods and Resultsmentioning

confidence: 99%

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Hot Electron Dynamics in InAs–AlAsSb Core–Shell Nanowires

Sandner,

Esmaielpour,

Giudice

et al. 2023

ACS Appl. Energy Mater.

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Semiconductor nanowires (NWs) have shown evidence of robust hot-carrier effects due to their small dimensions, making them attractive for advanced photoenergy conversion concepts. Especially, indium arsenide (InAs) NWs are promising candidates for harvesting hot carriers due to their high absorption coefficient, high carrier mobility, and large effective electron-to-hole mass difference. Here, we investigate the cooling and recombination dynamics of photoexcited hot carriers in pure and passivated InAs NWs by using ultrafast near-infrared pump−probe spectroscopy. We observe reduced Auger recombination in pure InAs NWs compared to that in passivated ones and associate this with charge-carrier separation by surface band bending. Similarly, faster carrier cooling by electron−hole scattering is observed in passivated InAs−AlAsSb NWs at high carrier densities in excess of 10 18 cm −3 , where hot electron lifetimes in this regime increase substantially with the pump fluence due to Auger heating. These results emphasize the importance of type-II alignment for charge-carrier separation in hot-carrier devices to suppress carriermediated cooling channels. In addition, a separate charge-carrier population lasting up to several nanoseconds is observed for photoexcitation of the NW shell. Despite the high conduction band offset, carrier migration is not observed in the range of 40 ps to 2 ns. This observation may open avenues for core−shell NW multijunction solar cells.

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Section: Experimental Methods and Resultssupporting

confidence: 55%

Section: Experimental Methods and Resultsmentioning

confidence: 99%

Section: Experimental Methods and Resultsmentioning

confidence: 99%

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Hot Electron Dynamics in InAs–AlAsSb Core–Shell Nanowires

Sandner,

Esmaielpour,

Giudice

et al. 2023

ACS Appl. Energy Mater.

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“…To realize site-selective growth, the Si (111) substrates were prepatterned by nanoimprint lithography (NIL) or electron beam lithography (EBL) to create mask patterns with different pitches 8 . For InAs-AlAsSb core-shell NWs, InAs cores were overgrown for 30 min with an AlAsSb shell at growth temperature of 425 °C and for another 10 min with a GaSb cap layer to prevent oxidation of the AlAsSb 9 . The arsenic content of the shell was 16 % to provide lattice matching between core and shell.…”

Section: Sample Preparationmentioning

confidence: 99%

Time resolved infrared spectroscopy for hot carrier dynamics in InAs-AlAsSb core-shell nanowires

Daniel¹,

Esmaielpour²,

Giudice³

et al. 2023

Physics, Simulation, and Photonic Engineering of Photovoltaic Devices XII

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Semiconductor nanowires (NWs) have shown robust hot carrier effects due to their small dimensions. Here, we study the cooling mechanisms of hot electrons in the time domain via transient absorption spectroscopy. Probe energies below the bandgap are used to determine the evolution of the carrier effective mass while probe energies above the bandgap track the conduction band occupation. From excitation intensity dependent measurements, we confirm that electron-hole interactions are a major cooling channel at large carrier density, given the high ratio of mh/me of InAs. Our experiments indicate that this cooling channel is amplified in passivated core-shell NWs. We associate this effect with spatial carrier separation caused by Fermi-level pinning in unpassivated NWs. In core-shell NWs, bands are considerably more flat which increases radiative recombination and electron-hole scattering with the latter cooling the hot electron population. Our results highlight the advantages of carrier separation if high carrier densities are to be used for hot phonon bottlenecks.

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“…Detailed faceting growth of GaSb in SAG and the formation of GaSb-related CS NWs have not been examined significantly because of the complex surface diffusion and surfactant effects of Sb adatoms. Selective-area molecular beam epitaxy grown InAs/AlInSb CS NWs have been investigated as passivation layers for core InAs NWs on Si, but shell roughness issues remain. Pyramidal GaSb structures surrounded with {1̅10} and {100} facets were formed via selective-area metalorganic vapor-phase epitaxy; however, excess Sb interrupted the nucleation process on a (111)B-oriented surface .…”

Section: Introductionmentioning

confidence: 99%

Selective-Area Growth of Vertical InGaAs/GaSb Core–Shell Nanowires on Silicon and Dual Switching Properties

Gamo,

Lian,

Motohisa

et al. 2023

ACS Nano

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The epitaxy of the Sb-related quantum well structure has been extensively investigated. However, the GaSb facet growth in selective-area growth (SAG) and GaSb nanostructures has not been investigated because of the surface diffusion complexity and surfactant effect of Sb adatoms. Here, the growth morphology of GaSb structures in SAG was characterized via InGaAs nanowires (NWs) monolithically grown on a Si template. SAG of GaSb using NWs included four growth processes: lateral-over growth along the ⟨1̅ 10⟩ directions, axial growth along the vertical ⟨111⟩ B direction, downward step-flow growth, and desorption of Sb adatoms from the NW sidewalls. The dominant processes could be controlled by the GaSb growth temperature and could form smooth GaSb shell layers. The vertical diode of InGaAs/GaSb core−shell NWs on Si exhibited moderate rectifying properties because of the InGaAs/GaSb heterojunction band alignment. In the vertical transistor application, specific dual-carrier modulation behaviors, such as p-channel field-effect transistor and n-channel tunnel field-effect transistor modes, occurred in the same transistor architecture. This was because the carrier transport changed with respect to the bias polarity. This specific transistor behavior in the InGaAs/GaSb core−shell NW on Si would expand possibilities for integrated circuit technologies using only a single transistor structure.

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Epitaxial type-I and type-II InAs-AlAsSb core–shell nanowires on silicon

Cited by 7 publications

References 49 publications

Hot Electron Dynamics in InAs–AlAsSb Core–Shell Nanowires

Hot Electron Dynamics in InAs–AlAsSb Core–Shell Nanowires

Time resolved infrared spectroscopy for hot carrier dynamics in InAs-AlAsSb core-shell nanowires

Selective-Area Growth of Vertical InGaAs/GaSb Core–Shell Nanowires on Silicon and Dual Switching Properties

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