On the Luminescence of VLS-grown GaAs-AlGaAs Core-Shell Nanowires and its Dependence on MOVPE Growth Conditions

AbstractWe report on the photoluminescence (PL) of GaAs-Al0.32Ga0.68As core-shell nanowires grown by MOVPE, and their dependence on the precursors V:III molar ratio utilised in the vapor during growth. It is shown that the PL emission of the GaAs nanowire core red-shifts with decreasing the V:III ratio from 30:1 to 4:1, an effect tentatively ascribed to the build-up of a space-charge region at the core-shell hetero-interface, the latter associated to the unintentional incorporation of impurities, namely C in GaAs and Si in AlGaAs.

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Bi Incorporation and Segregation in the MBE-Grown GaAs-(Ga,Al)As-Ga(As,Bi) Core-Shell Nanowires

10.21203/rs.3.rs-985481/v1 ◽

2021 ◽

Author(s):

Janusz Sadowski ◽

Anna Kaleta ◽

Serhii Kryvyi ◽

Dorota Janaszko ◽

Bogusława Kurowska ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Molecular Beam ◽

Flux Ratio ◽

Growth Conditions ◽

Nanowire Growth ◽

Core Shell ◽

Zinc Blende ◽

Transmission Electron ◽

Shell Nanowires

Abstract Incorporation of Bi into GaAs-(Ga,Al)As-Ga(As,Bi) core-shell nanowires grown by molecular beam epitaxy is studied with transmission electron microscopy. Nanowires are grown on GaAs(100) substrates with Au-droplet assisted mode. Bi-doped shells are grown at low temperature (300 °C) with a close to stoichiometric Ga/As flux ratio. At low Bi fluxes, the Ga(As,Bi) shells are smooth, with Bi completely incorporated into the shells. Higher Bi fluxes (Bi/As flux ratio ~ 4%) led to partial segregation of Bi as droplets on the nanowires sidewalls, preferentially located at the nanowire segments with wurtzite structure. We demonstrate that such Bi droplets on the sidewalls act as catalysts for the growth of branches perpendicular to the GaAs trunks. Due to the tunability between zinc-blende and wurtzite polytypes by changing the nanowire growth conditions, this effect enables fabrication of branched nanowire architectures with branches generated from selected (wurtzite) nanowire segments.

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MOVPE growth of GaP/GaPN core–shell nanowires: N incorporation, morphology and crystal structure

Nanotechnology ◽

10.1088/1361-6528/aaf607 ◽

2019 ◽

Vol 30 (10) ◽

pp. 104002 ◽

Cited By ~ 6

Author(s):

Matthias Steidl ◽

Klaus Schwarzburg ◽

Beatriz Galiana ◽

Thomas Kups ◽

Oliver Supplie ◽

...

Keyword(s):

Crystal Structure ◽

Core Shell ◽

Movpe Growth ◽

N Incorporation ◽

Shell Nanowires

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The influence of MOVPE growth conditions on the shell of core-shell GaN microrod structures

Journal of Crystal Growth ◽

10.1016/j.jcrysgro.2017.02.035 ◽

2017 ◽

Vol 465 ◽

pp. 34-42 ◽

Cited By ~ 6

Author(s):

Tilman Schimpke ◽

Adrian Avramescu ◽

Andreas Koller ◽

Amalia Fernando-Saavedra ◽

Jana Hartmann ◽

...

Keyword(s):

Growth Conditions ◽

Core Shell ◽

Movpe Growth

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One-Dimensional TiO2@GaON Core-Shell Nanowires with Controlled Shell Thickness from Atomic Layer Deposition for Stable and Efficient Photoelectrochemical Water Splitting

10.26434/chemrxiv.9199796 ◽

2019 ◽

Author(s):

Jiajia Tao ◽

Hong-Ping Ma ◽

Kaiping Yuan ◽

Yang Gu ◽

Jianwei Lian ◽

...

Keyword(s):

Atomic Layer Deposition ◽

Band Gap ◽

Water Splitting ◽

Atomic Layer ◽

Photoelectrochemical Water Splitting ◽

Core Shell ◽

Photoelectrochemical Performance ◽

Highly Efficient ◽

Layer Deposition ◽

Shell Nanowires

<div>As a promising oxygen evolution reaction semiconductor, TiO2 has been extensively investigated for solar photoelectrochemical water splitting. Here, a highly efficient and stable strategy for rationally preparing GaON cocatalysts on TiO2 by atomic layer deposition is demonstrated, which we show significantly enhances the</div><div>photoelectrochemical performance compared to TiO2-based photoanodes. For TiO2@20 nm-GaON core-shell nanowires a photocurrent density up to 1.10 mA cm-2 (1.23 V vs RHE) under AM 1.5 G irradiation (100 mW cm-2) has been achieved, which is 14 times higher than that of TiO2 NWs. Furthermore, the oxygen vacancy formation on GaON as well as the band gap matching with TiO2 not only provides more active sites for water oxidation but also enhances light absorption to promote interfacial charge separation and migration. Density functional theory studies of model systems of GaON-modified TiO2 confirm the band gap reduction, high reducibility and ability to activate water. The highly efficient and stable systems of TiO2@GaON core-shell nanowires provide a deeper understanding and universal strategy for enhancing photoelectrochemical performance of photoanodes now available. </div>

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