Atomic structure and bonding of the interfacial bilayer between Au nanoparticles and epitaxially regrown MgAl2O4 substrates

Zhu, Guo‐zhen; Majdi, Tahereh; Shao, Yang; Bugnet, Matthieu; Preston, J. S.; Botton, Gianluigi A.

doi:10.1063/1.4902939

Cited by 16 publications

(11 citation statements)

References 26 publications

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“…Nanowires are usually with rectangular pyramid bases elongated along [001] rutile . These bases, similar to those in other gold-oxide systems, [25][26][27][28] grow before the nanowires.…”

Section: Titanium Dioxidesupporting

confidence: 70%

Kinetically Favorable Vapor–Adsorbate–Solid Growth of Rutile Nanowires

et al. 2019

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The vapor‐based synthesis of nanowires, particularly vapor–liquid–solid growth and its variants, is an undoubtedly promising method for fabricating high‐quality silicon‐based and group III–V semiconductors. However, the assembly of oxide nanowires has limited success while adopting these methods. Herein, a simple and scalable approach is developed to synthesize single‐crystal oxide nanowires with controllable morphology. Using titanium oxide as the model system for validation, this approach emphasizes the essential role of the surface characteristic of the seed for the space‐confined growth of nanowires. The shape and growth directions of nanowires can be additionally tailored by using bimetallic seeds, with compositional segregations and dissimilar surface characteristics. Since the source material has the same thermodynamic conditions as the produced nanowires within a closed vessel, the results suggest that the growth of nanowires can be dominated by the kinetic enrichment at seed surfaces or referred to as kinetically favorable vapor–adsorbate–solid growth. While identifying the key thermodynamic and kinetic parameters during growth, this approach is applicable for a wide range of materials.

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“…Nanowires are usually with rectangular pyramid bases elongated along [001] rutile . These bases, similar to those in other gold-oxide systems, [25][26][27][28] grow before the nanowires.…”

Section: Titanium Dioxidesupporting

confidence: 70%

Kinetically Favorable Vapor–Adsorbate–Solid Growth of Rutile Nanowires

et al. 2019

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“…Gold nanoparticles supported on MgAl 2 O 4 single crystals were prepared by a thermal dewetting method. When the thin film is heated up to >900 °C, the in-plane orientation of gold nanoparticles shows a preferred orientation [10] These distributed gold nanoparticles [14] have a 〈111〉 fiber texture, i.e., {111} Au parallel to the substrate surfaces.…”

Section: Doi: 101002/admi201701664mentioning

confidence: 99%

“…[9] Besides, atomic reconstruction of interfacial structure has been experimentally observed in a lattice-matched system of Au/ MgAl 2 O 4 . [10,11] The thermally stable interface consists of sparsely arranged gold atoms with a well-defined periodicity. Such interface reconstruction could be ascribed to phase-like behaviors, referring to structure transitioning as a function of temperature and composition, because Au/MgAl 2 O 4 interface displays distinctive atomic arrangement under particular thermodynamic conditions.…”

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confidence: 99%

Temperature‐Induced Atomic Reconstruction At Au/MgAl₂O₄ Interfaces

Liu

Xie

Bugnet

et al. 2018

Adv Materials Inter

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e.g., Co/Al 2 O 3 or Co/SrTiO 3 ) [4] and the switching polarity (e.g., Pt/TiO 2 [5] ) for memory and other electronic applications. Despite a variety of excellent properties associated with metal-oxide interfaces, the microscopic nature of metal-oxide interfaces is still a matter of debate.The structural mismatch across nonreactive metal-oxide interfaces often results in the formation of steps, [7] misfit dislocations, [8] and periodic structural units [9] in the interface. For example, misfit dislocation networks are observed in the Nb/Al 2 O 3 interface [8] and the termination Ni layer is periodically buckled in the Ni/Al 2 O 3 interface. [9] Besides, atomic reconstruction of interfacial structure has been experimentally observed in a lattice-matched system of Au/ MgAl 2 O 4 . [10,11] The thermally stable interface consists of sparsely arranged gold atoms with a well-defined periodicity. Such interface reconstruction could be ascribed to phase-like behaviors, referring to structure transitioning as a function of temperature and composition, because Au/MgAl 2 O 4 interface displays distinctive atomic arrangement under particular thermodynamic conditions. Such phase-like characters have been intensively studied in the case of segregated grain boundaries in doped metals [12] and oxides [13] for their broad applications in comprehending microstructure evolution and materials properties.Here, we studied the structural characters of heat-treated Au-MgAl 2 O 4 interfaces. Gold nanoparticles supported on MgAl 2 O 4 single crystals were prepared by a thermal dewetting method. 10 nm thick gold films were deposited on (111) MgAl2O4 surfaces, heated to 600-1100 °C for 10-90 min with a heating rate of 10 °C min −1 , and then rapidly cooled to freeze their high-temperature states in 5 min or slowly cooled down to room temperatures within 5 h. During the heat treatment, continuous gold films break into gold nanoparticles (see details in the Supporting Information). These distributed gold nanoparticles [14] have a 〈111〉 fiber texture, i.e., {111} Au parallel to the substrate surfaces. X-ray diffraction analysis shows that the in-plane orientation of gold nanoparticles is random [11] for a thin film heated up to a temperature lower than 900 °C. When the thin film is heated up to >900 °C, the in-plane orientation of gold nanoparticles shows a preferred orientation [10] {111} Au ||{111} MgAl2O4 and 〈 〉 110 Au ||〈 〉 110 MgAl2O4 and its twins. In this work, we aim to understand interface structures associated with the formation of the in-plane orientation {111} Au ||{111} MgAl2O4 and 〈 〉 110 Au ||〈 〉 110 MgAl2O4 . We observed three different Au/MgAl 2 O 4 interfacesThe metal-oxide interaction, associated with intermingling delocalization of bonding electrons in metals and ionic bonds in oxides, may cause reconstruction of interface structure and accordingly affect physical properties of heterogeneous materials. This Communication reports reconstructions of (111) interface between gold and magnesium aluminate spinel according to ...

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“…Atomic reconstructions at interfaces have been experimentally observed in a lattice-matched system of Au/MgAl 2 O 4 (spinel, (111)-oriented). [5][6][7] The gold lattice aligns with oxide substrates after the heat treatment at high temperatures. As shown in Fig.1, three different interfaces, including the one with direct adhesion of Au and Al(O) layer of MgAl 2 O 4 , monolayer, and two-layer interfaces, form over a temperature range up to the melting point of gold, according to experimental observation and theoretical prediction.…”

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confidence: 99%