Facet-Related Non-uniform Photoluminescence in Passivated GaAs Nanowires

The semiconductor nanowire architecture provides opportunities for non-planar electronics and optoelectronics arising from its unique geometry. This structure gives rise to a large surface area-to-volume ratio and therefore understanding the effect of nanowire surfaces on nanowire optoelectronic properties is necessary for engineering related devices. We present a systematic study of the non-uniform optical properties of Au-catalyzed GaAs/AlGaAs core–shell nanowires introduced by changes in the sidewall faceting. Significant variation in intra-wire photoluminescence (PL) intensity and PL lifetime (τPL) was observed along the nanowire axis, which was strongly correlated with the variation of sidewall facets from {112} to {110} from base to tip. Faster recombination occurred in the vicinity of {112}-oriented GaAs/AlGaAs interfaces. An alternative nanowire heterostructure, the radial quantum well tube consisting of a GaAs layer sandwiched between two AlGaAs barrier layers, is proposed and demonstrates superior uniformity of PL emission along the entire length of nanowires. The results emphasize the significance of nanowire facets and provide important insights for nanowire device design.

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Multiband model of the valence-band electronic structure in cylindrical GaAs nanowires

Hemijska industrija ◽

10.2298/hemind091221028c ◽

2010 ◽

Vol 64 (3) ◽

pp. 165-170

Author(s):

Nemanja Cukaric ◽

Milan Tadic

Keyword(s):

Energy Levels ◽

Outer Radius ◽

Dispersion Relations ◽

Core Shell ◽

Type I ◽

Free Standing ◽

Gaas Nanowires ◽

Multiband Model ◽

Shell Nanowires

We compute the hole states in the GaAs free-standing nanowires, and in the GaAs/(Al,Ga)As core-shell nanowires of type I-s, which are grown along the [100] direction. The hole states are extracted from the 4-band Luttinger-Kohn Hamiltonian, which explicitly takes into account mixing between the light and heavy holes. The axial aproximation is adopted, which allowed classification of states according to the total angular monentum (fz when expressed in units of the Planck constant). The envelope functions are expanded in Bessel functions of the first kind. The dispersion relations of the subbands E(kz) obtained by the devised method do not resemble parabolas, which is otherwise a feature of the dispersion relations of the conduction subbands. Furthermore, the energy levels of holes whose total orbital momentum is fz=1/2 are shown to cross for a free-standing wire. The low energy fz=1/2 states are found to anticross, but these anticrossings turn into crossings when the ratio of the inner and outer radius of the core-shell wire takes a certain value. The influence of the geometric parameters on the dispersion relations is considered for both free standing and core-shell nanowires.

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Unexpected benefits of stacking faults on the electronic structure and optical emission in wurtzite GaAs/GaInP core/shell nanowires

Nanoscale ◽

10.1039/c9nr01213c ◽

2019 ◽

Vol 11 (18) ◽

pp. 9207-9215 ◽

Cited By ~ 9

Author(s):

Xiaoming Yuan ◽

Lin Li ◽

Ziyuan Li ◽

Fan Wang ◽

Naiyin Wang ◽

...

Keyword(s):

Electronic Structure ◽

Stacking Faults ◽

Optical Emission ◽

Carrier Dynamics ◽

Core Shell ◽

Gaas Nanowires ◽

Shell Nanowires

Superior passivation of GaInP shell and the revealed carrier dynamics in WZ polytype GaAs nanowires.

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

MRS Proceedings ◽

10.1557/proc-1206-m11-36 ◽

2009 ◽

Vol 1206 ◽

Author(s):

Paola Prete ◽

Nico Lovergine ◽

Ilio Miccoli ◽

Fabio Marzo ◽

Joan S. Burger ◽

...

Keyword(s):

Space Charge ◽

Space Charge Region ◽

Growth Conditions ◽

Molar Ratio ◽

Core Shell ◽

The Core ◽

Movpe Growth ◽

Gaas Nanowire ◽

Pl Emission ◽

Shell Nanowires

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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Effects of Growth Parameters on SiC/SiO2 Core/Shell Nanowires Radial Structures

Materials Science Forum ◽

10.4028/www.scientific.net/msf.740-742.494 ◽

2013 ◽

Vol 740-742 ◽

pp. 494-497 ◽

Cited By ~ 8

Author(s):

Sathish Chander Dhanabalan ◽

Marco Negri ◽

Francesca Rossi ◽

Giovanni Attolini ◽

Marco Campanini ◽

...

Keyword(s):

Growth Parameters ◽

Ionic Surfactant ◽

Core Shell ◽

Catalytic Layer ◽

Strongly Correlated ◽

Core Diameter ◽

The Core ◽

Nanowires Growth ◽

Cubic Silicon Carbide ◽

Shell Nanowires

Cubic silicon carbide - silicon dioxide core-shell nanowires have been synthesized in a thermal CVD system from carbon monoxide on silicon substrate. Using a non-ionic surfactant during the coating process of the substrate by the catalyst, the uniformity of the catalytic layer was improved, resulting in a more uniform nanowires growth. It is demonstrated that the core diameter is strongly correlated with the precursor concentration.

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Improved light emission of MoS2 monolayers by constructing AlN/MoS2 core–shell nanowires

Journal of Materials Chemistry C ◽

10.1039/c7tc03231e ◽

2017 ◽

Vol 5 (39) ◽

pp. 10225-10230 ◽

Cited By ~ 6

Author(s):

Fei Chen ◽

Ting Wang ◽

Lei Wang ◽

Xiaohong Ji ◽

Qinyuan Zhang

Keyword(s):

Charge Transfer ◽

Light Emission ◽

Hybrid Structure ◽

Core Shell ◽

One Dimensional ◽

Pl Emission ◽

Mos2 Monolayers ◽

Shell Nanowires

Hybrid structure of one-dimensional AlN/1L-MoS2 core–shell nanowires exhibited enhanced PL emission due to the charge transfer across the interface of the heterostructure.

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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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