Influence of Bi on embedded nanocrystal formation and thermoelectric properties of GaAs

Warren, Michael V.; Canniff, J. C.; Chi, Hang; Naab, F.; Stoica, Vladimir; Clarke, Roy; Uher, Ctirad; Goldman, R. S.

doi:10.1063/1.4906992

Cited by 3 publications

(1 citation statement)

References 24 publications

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“…On the other hand, we observe a hemispherical shape at the top of GaAsBi/GaAs NWs, which may stem from the introduction of Bi during growth . This characteristic surface morphology is considered to be related to the strain effect induced by the introduction of Bi. , Furthermore, the surface diffusion and the droplet formation of the Bi atoms at the growth front can modify the resulting wire shape. − This growth mechanism will be discussed further below through TEM investigations.…”

Section: Resultsmentioning

confidence: 78%

Metamorphic GaAs/GaAsBi Heterostructured Nanowires

et al. 2015

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GaAs/GaAsBi coaxial multishell nanowires were grown by molecular beam epitaxy. Introducing Bi results in a characteristic nanowire surface morphology with strong roughening. Elemental mappings clearly show the formation of the GaAsBi shell with inhomogeneous Bi distributions within the layer surrounded by the outermost GaAs, having a strong structural disorder at the wire surface. The nanowire exhibits a predominantly ZB structure from the bottom to the middle part. The polytipic WZ structure creates denser twin defects in the upper part than in the bottom and middle parts of the nanowire. We observe room temperature cathodoluminescence from the GaAsBi nanowires with a broad spectral line shape between 1.1 and 1.5 eV, accompanied by multiple peaks. A distinct energy peak at 1.24 eV agrees well with the energy of the reduced GaAsBi alloy band gap by the introduction of 2% Bi. The existence of localized states energetically and spatially dispersed throughout the NW are indicated from the low temperature cathodoluminescence spectra and images, resulting in the observed luminescence spectra characterized by large line widths at low temperatures as well as by the appearance of multiple peaks at high temperatures and for high excitation powers.

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Section: Resultsmentioning

confidence: 78%

Metamorphic GaAs/GaAsBi Heterostructured Nanowires

et al. 2015

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Enhancement of thermoelectric cooling by hot-end electroluminescence

Yang

et al. 2022

Energy Conversion and Management

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Thermoelectric properties of semiconductor-metal composites produced by particle blending

et al. 2016

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In the quest for more efficient thermoelectric material able to convert thermal to electrical energy and vice versa, composites that combine a semiconductor host having a large Seebeck coefficient with metal nanodomains that provide phonon scattering and free charge carriers are particularly appealing. Here, we present our experimental results on the thermal and electrical transport properties of PbS-metal composites produced by a versatile particle blending procedure, and where the metal work function allows injecting electrons to the intrinsic PbS host. We compare the thermoelectric performance of composites with microcrystalline or nanocrystalline structures. The electrical conductivity of the microcrystalline host can be increased several orders of magnitude with the metal inclusion, while relatively high Seebeck coefficient can be simultaneously conserved. On the other hand, in nanostructured materials, the host crystallites are not able to sustain a band bending at its interface with the metal, becoming flooded with electrons. This translates into even higher electrical conductivities than the microcrystalline material, but at the expense of lower Seebeck coefficient values.Peer ReviewedPostprint (published version

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Influence of Bi on embedded nanocrystal formation and thermoelectric properties of GaAs

Cited by 3 publications

References 24 publications

Metamorphic GaAs/GaAsBi Heterostructured Nanowires

Metamorphic GaAs/GaAsBi Heterostructured Nanowires

Enhancement of thermoelectric cooling by hot-end electroluminescence

Thermoelectric properties of semiconductor-metal composites produced by particle blending

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