Thermal transport in twinning superlattice and mixed-phase GaAs nanowires

Ghukasyan, Ara; LaPierre, Ray

doi:10.1039/d2nr00720g

Cited by 5 publications

(5 citation statements)

References 39 publications

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“…It is interesting to compare these results with those recently reported by Ghukasyan and LaPierre. 57 They studied fully twinned GaAs TSL, like those we considered in Figure 7 , though they explicitly accounted for the NW geometry, studying systems with diameters of at most 10 nm. They observe a deep and well-defined minimum at small periods, while we see a saturation.…”

Section: Resultsmentioning

confidence: 99%

Phonon Transport in GaAs and InAs Twinning Superlattices

et al. 2022

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Crystal phase engineering gives access to new types of periodic nanostructures, such as the so-called twinning superlattices, where the motif of the superlattice is determined by a periodic rotation of the crystal. Here, by means of atomistic nonequilibrium molecular dynamics calculations, we study to what extent these periodic systems can be used to alter phonon transport in a controlled way, similar to what has been predicted and observed in conventional superlattices based on heterointerfaces. We focus on twinning superlattices in GaAs and InAs and highlight the existence of two different transport regimes: in one, each interface behaves like an independent scatterer; in the other, a segment with a sufficiently large number of closely spaced interfaces is seen by propagating phonons as a metamaterial with its own thermal properties. In this second scenario, we distinguish the case where the phonon mean free path is smaller or larger than the superlattice segment, pointing out a different dependence of the thermal resistance with the number of interfaces.

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Section: Resultsmentioning

confidence: 99%

Phonon Transport in GaAs and InAs Twinning Superlattices

et al. 2022

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“…The decrease in NW radius is attributed to the suppression of surface diffusion of Ga adatoms on the NW sidewalls by the Te dopant atoms and the radius oscillations to the existence of two stable orientations of the narrowing and widening sidewall facets. These results may have applications in thermoelectrics , and crystal phase quantum dots − where ultrathin NWs are desired. Ultrathin nanoantenna may also have photonic applications, for example, as short-wavelength absorbers in NW-based photodetectors …”

Section: Introductionmentioning

confidence: 95%

Ultrathin Te-Doped GaP Nanoantenna with Crystal Phase Transitions

Diak

Thomas

Dubrovskiı̆

et al. 2023

Crystal Growth & Design

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We report Te-doped GaP nanowires (NWs) with positive tapering and radii measuring as low as 5 nm grown by the self-assisted vapor–liquid–solid mechanism using selective-area molecular beam epitaxy. The occurrence of the ultrathin nanoantenna showed a dependence on pattern pitch (separation between NWs) with a predominance at 600 nm pitch, and exhibited radius oscillations that correlate with polytypic zincblende/wurtzite segments. A growth model explains the positive tapering of the NW leading to an ultrathin tip from the suppression of surface diffusion of Ga adatoms on the NW sidewalls by Te dopant flux. The model also provides a relationship between the radius modulations and the oscillations of the droplet contact angle, predicting the quasi-periodic radius oscillations and corresponding crystal phase transitions. These results establish a link between dopants and the ability to control NW morphology and crystal phase with possible applications in thermoelectrics, quantum emitters, and photodetectors.

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“…This makes SL NWs an ideal platform to envisage and study phonon engineering at the nanoscale for controlled heat transport. In recent years, there has been an increase in both the theoretical and experimental studies of SL NWs with a focus on their thermal properties. ,− Most of the work done in NW SLs from the perspective of phonon engineering explores twinning or crystal phase SLs. In this work, we study the phononic properties of SL NWs made of two different constituent materials: GaAs and GaP.…”

Section: Introductionmentioning

confidence: 99%

GaAs/GaP Superlattice Nanowires for Tailoring Phononic Properties at the Nanoscale: Implications for Thermal Engineering

K. Sivan,

Abad,

Albrigi

et al. 2023

ACS Appl. Nano Mater.

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The possibility to tune the functional properties of nanomaterials is key to their technological applications. Superlattices, i.e., periodic repetitions of two or more materials in one or more dimensions, are being explored for their potential as materials with tailor-made properties. Meanwhile, nanowires offer a myriad of possibilities to engineer systems at the nanoscale, as well as to combine materials that cannot be put together in conventional heterostructures due to the lattice mismatch. In this work, we investigate GaAs/GaP superlattices embedded in GaP nanowires and demonstrate the tunability of their phononic and optoelectronic properties by inelastic light scattering experiments corroborated by ab initio calculations. We observe clear modifications in the dispersion relation for both acoustic and optical phonons in the superlattices nanowires. We find that by controlling the superlattice periodicity, we can achieve tunability of the phonon frequencies. We also performed wavelength-dependent Raman microscopy on GaAs/GaP superlattice nanowires, and our results indicate a reduction in the electronic bandgap in the superlattice compared to the bulk counterpart. All of our experimental results are rationalized with the help of ab initio density functional perturbation theory (DFPT) calculations. This work sheds fresh insights into how material engineering at the nanoscale can tailor phonon dispersion and open pathways for thermal engineering.

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Thermal transport in twinning superlattice and mixed-phase GaAs nanowires

Abstract: With continuing advances in semiconductor nanowire (NW) growth technologies, synthesis of tailored crystal structures is gradually becoming a reality. Mixtures of the bulk zincblende (ZB) and wurtzite (WZ) phase can...

Cited by 5 publications

References 39 publications

Phonon Transport in GaAs and InAs Twinning Superlattices

Phonon Transport in GaAs and InAs Twinning Superlattices

Ultrathin Te-Doped GaP Nanoantenna with Crystal Phase Transitions

GaAs/GaP Superlattice Nanowires for Tailoring Phononic Properties at the Nanoscale: Implications for Thermal Engineering

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