Amorphous silica nanowires: Intensive blue light emitters

Yu, Dapeng; Hang, Qingling; Ding, Yu; Zhang, Hongzhou; Bai, Z. G.; Wang, Jing Jing; Zou, Yinghua; Qian, Wenliang; Xiong, Gengyan; Feng, Sun

doi:10.1063/1.122677

Cited by 520 publications

(350 citation statements)

References 16 publications

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“…In all these cases, however, the connected four-ring columnar skeleton is maintained, which still appears to be the energetically favored structural route to obtain the lowest energy for this size range. The stability of nanoscale columnar SiO 2 N clusters possessing reactive defective ends naturally provides a route to linear coalescence, perhaps linked to the high temperature synthesis of silica nanowires [20].…”

Section: -2mentioning

confidence: 99%

Columnar-to-Disk Structural Transition in Nanoscale(SiO2)NClusters

Bromley

Flikkema

2005

Phys. Rev. Lett.

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Extensive large-scale global optimizations refined by ab initio calculations are used to propose SiO 2 N N 14-27 ground states. For N < 23 clusters are columnar and show N-odd-N-even stability, energetically and electronically. At N 23 a columnar-to-disk structural transition occurs reminiscent of that observed for Si N . These transitions differ in nature but have the same basis, linking the nanostructural behavior of an element (Si) and its oxide (SiO 2 ). Considering the impact of devices based on the nanoscale manipulation of Si=SiO 2 the result is of potential technological importance. DOI: 10.1103/PhysRevLett.95.185505 PACS numbers: 61.46.+w, 36.40.Ei, 36.40.Mr, 68.65.2k The technological importance of nanoscale silica (SiO 2 ) can hardly be overstated considering its established utilization in microelectronics, catalysis, and composite materials and its promise in the emerging field of photonics. Although much experimental and theoretical work has focused upon the stabilities and structures of the many silica bulk polymorphs and their surfaces, the low energy structures and potential energy surface (PES) of nanoscale SiO 2 clusters is relatively unknown. In this Letter we provide the beginnings of an energetic baseline of the complex PES of nanoscale SiO 2 by finding the lowest energy forms of silica for SiO 2 N N 14-27 providing new limits on the stability of this centrally important material in the physical, chemical, and geophysical sciences. The clusters we study all have at least one dimension between 1 and 2.5 nm and are all substantially lower in energy than any previously reported. Our results strongly indicate that one-dimensional columnar structures are energetically favored up to a length scale of at least 2 nm where upon a transition to two-dimensional trigonal disklike structures occurs at N 23. The transition is characterized by sharp changes in measures of the structural form, electronic structure, and bonding topology of the cluster series, but appears smooth with respect to cluster energies. The structural transition in SiO 2 N clusters is compared to that known for clusters of its parent element Si N [1]. In both cases for N 23-25 a structural transition from elongated to more compact forms appears to occur in the thermodynamically preferred clusters [2]. Usually oxides and their parent elements display different but complementary physical and chemical properties and typically bear little structural relation to one another. Our finding that, at the nanoscale, the size-dependent structural behavior of SiO 2 and its parent element follow a similar general pattern is at once relatively unexpected and fundamentally suggests an inherent link between the two materials. Because of the immense dependence on the combined structural and physical properties of both nanoscale Si and SiO 2 in electronic and optical devices, our demonstration of such a connection is of potential significant technological importance.Although relatively small, M 20 homogeneous clusters of low atomic weight atoms are...

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Section: -2mentioning

confidence: 99%

Columnar-to-Disk Structural Transition in Nanoscale(SiO2)NClusters

Bromley

Flikkema

2005

Phys. Rev. Lett.

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“…17 Recently, SiO 2 nanowires have shown a great promise as functional and structural nanobuilding blocks in nanoelectronics. Various methods, such as chemical vapor deposition ͑CVD͒, 18,[23][24][25] laser ablation, 26 sol-gel, 27 and thermal evaporation methods, 28 have been used to produce SiO 2 nanowires on a large scale, from well-aligned to nanoflower morphology. 18,19 In order to integrate these nanowires into functional nanodevices, a precise measurement of the mechanical properties is of significant importance, because mechanical failure of these nanobuilding blocks may lead to the malfunction or even fatal failure of the entire devices.…”

mentioning

confidence: 99%

Elastic modulus of amorphous SiO2 nanowires

Gao

2006

Applied Physics Letters

144

106

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Amorphous SiO2 nanowires with diameter ranging from 50 to 100 nm were synthesized using chemical vapor deposition (CVD) under an argon atmosphere at atmospheric pressure. Nanoscale three-point bending tests were performed directly on individual amorphous SiO2 nanowires using an atomic force microscope (AFM). Elastic modulus of the amorphous SiO2 nanowires was measured to be 76.6±7.2GPa, which is close to the reported value of the bulk SiO2 and thermally grown SiO2 thin films, but lower than that of plasma-enhanced CVD SiO2 thin films. The amorphous SiO2 nanowires exhibit brittle fracture failure in bending.

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“…3). We can therefore conclude that the growth mechanism of the silica nanowires does not follow a regular VLS model 1) arising, for example, from unintentional metal contamination. However, for all four types of Ge nanostructure, a high temperature anneal over 850°C is required to grow the nanowires.…”

Section: Discussionmentioning

confidence: 99%

“…Silica nanowires have potential applications in Si-based optoelectronics, where for example they could be used as on-chip optical interconnects or light emitters. 1) Interest in this latter application has been fuelled by the discovery of stable and strong blue light emission from silica nanowires. 1) Intensive research has been carried out on the growth of silica nanowires using techniques such as pulsed laser ablation, 2) catalytic chemical vapor deposition (CVD), 3) and carbothermal reduction.…”

Section: Introductionmentioning

confidence: 99%

“…1) Intensive research has been carried out on the growth of silica nanowires using techniques such as pulsed laser ablation, 2) catalytic chemical vapor deposition (CVD), 3) and carbothermal reduction. 4) At the same time, the growth mechanism has been investigated and several growth models have been proposed, such as the vapor-liquid-solid (VLS) model, 1,5) the vapor-solid (VS) model, 6) and the solid-liquid-solid (SLS) model. 7) However the growth mechanism is still poorly understood.…”

Section: Introductionmentioning

confidence: 99%

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Metal-Catalyst-Free Growth of Silica Nanowires and Carbon Nanotubes Using Ge Nanostructures

Uchino

Hutchison

Ayre

et al. 2011

Jpn. J. Appl. Phys.

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The use of Ge nanostructures is investigated for the metal-catalyst-free growth of silica nanowires and carbon nanotubes (CNTs). Silica nanowires with diameters of 10-50 nm and lengths of ≤ 1 µm were grown from SiGe islands, Ge dots, and Ge nanoparticles. High-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS) reveal that the nanowires grow from oxide nanoparticles on the sample surface. We propose that the growth mechanism is thermal diffusion of oxide through the GeO 2 nanostructures. CNTs with diameters 0.6-2.5 nm and lengths of less than a few µm were similarly grown by chemical vapor deposition from different types of Ge nanostructures. Raman measurements show the presence of radial breathing mode peaks and the absence of the disorder induced D-band, indicating single walled CNTs with a low defect density. HRTEM images reveal that the CNTs also grow from oxide nanoparticles, comprising a mixture of GeO 2 and SiO 2

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Amorphous silica nanowires: Intensive blue light emitters

Cited by 520 publications

References 16 publications

Columnar-to-Disk Structural Transition in Nanoscale(SiO2)NClusters

Columnar-to-Disk Structural Transition in Nanoscale(SiO2)NClusters

Elastic modulus of amorphous SiO2 nanowires

Metal-Catalyst-Free Growth of Silica Nanowires and Carbon Nanotubes Using Ge Nanostructures

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