Vertically Aligned Hybrid Core/Shell Semiconductor Nanowires for Photonics Applications

Macías-Montero, Manuel; Filippin, A. Nicolas; Saghi, Zineb; Aparicio, Francisco J.; Barranco, Ángel; Espinós, J.P.; Frutos, F.; González‐Elipe, Agustín R.; Borrás, Ana

doi:10.1002/adfm.201301120

Cited by 37 publications

(79 citation statements)

References 58 publications

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“…12,36−39 In this article, we take advantage of a recently developed method consisting of the alignment of the ONWs driven by electrostatic interaction with the plasma-sheath electric field. 19,21,28 The protocol involves the formation of an inorganic shell that acts as a scaffold that maintains the vertical orientation of the ONWs once the plasma is switched off. In practice, the FePcCl and FePc ONWs reach vertical alignment by growing by PECVD 40 a SiO 2 conformal shell.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Self-Assembly of the Nonplanar Fe(III) Phthalocyanine Small-Molecule: Unraveling the Impact on the Magnetic Properties of Organic Nanowires

et al. 2018

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In this article we show for the first time the formation of magnetic supported organic nanowires (ONWs) driven by self-assembly of a nonplanar Fe(III) phthalocyanine chloride (FePcCl) molecule. The ONWs grow by a crystallization mechanism on roughness-tailored substrates. The growth methodology consists of a vapor deposition under low vacuum and mild temperature conditions. The structure, microstructure, and chemical composition of the FePcCl NWs are thoroughly elucidated and compared with those of Fe(II) phthalocyanine NWs by a consistent and complementary combination of advanced electron microscopies and X-ray spectroscopies. In a further step, we vertically align the NWs by conformal deposition of a SiO 2 shell. Such orientation is critical to analyze the magnetic properties of the FePcCl and FePc supported NWs. A ferromagnetic behavior below 30 K with an easy axis perpendicular to the phthalocyanine plane was observed in the two cases with the FePcCl nanowires presenting a wider hysteresis. These results open the path to the fabrication of nanostructured one-dimensional small-molecule spintronic devices. T ailoring material structure at the nanoscale has prompted research on new and exciting properties over the last two decades. This is particularly true for one-dimensional (1D) nanostructures (nanotubes, nanowires, nanorods, or nanobelts) with longitudinal sizes orders of magnitude larger than the cross-sectional sizes.1 Among them, organic nanowires (ONWs) form a family of nanostructures with remarkable optic, electronic, sensing, and wetting properties.2−12 In addition, the development of ONW devices offers potential for low cost and flexible devices and versatility through the molecular design of their building blocks. The methods for the synthesis of these 1D systems generally rely on three approaches including template procedures, solution-phase deposition, and vapor transport. [2][3][4]6,10,13 Condensation from the vapor phase at low pressure (or simply physical vapor deposition, PVD) counts within the last group and presents interesting features such as (i) direct formation of single crystal nanowires with controlled morphology on different substrates; (ii) high adaptability to a large amount of different π-conjugated small molecules; (iii) high growth rate and controlled density of nanowires with appropriated homogeneity; (iv) solventless and one-step synthesis; and (v) straightforward compatibility with other vacuum deposition and processing methods. 2,14−18 The method consists of the low-pressure sublimation of purely organic or metalorganic small-molecules from the bulk crystals counterpart and their condensation on the surface of diverse supports. These molecules self-assemble into supported single-crystal nanowires tens of nanometers in width and several micrometers in length.14,15,18 Such a heterogeneous crystallization process can be enhanced by including nucleation centers at the substrate to trigger the preferential condensation of molecules on those spots.14,15 Formation of ONWs...

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Section: ■ Results and Discussionmentioning

confidence: 99%

Self-Assembly of the Nonplanar Fe(III) Phthalocyanine Small-Molecule: Unraveling the Impact on the Magnetic Properties of Organic Nanowires

et al. 2018

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“…To this end, our group has developed different plasma approaches for the deposition of nanofibers, nanorods and nanowires made of inorganic semiconductors (TiO 2 and ZnO) [568], small-molecules [569] and hybrid and heterostructured nanostructures (metal@metal-oxide [186][187][188]563] and organic@inorganic core@shell nanowires [570]) that can be activated by light illumination. Furthermore, by tailoring the density, morphology and chemical characteristics of these 1D nanostructures, we have been able to fabricate ultrahydrophobic surfaces; i.e., surfaces with an apparent WCA of 180° [242,569].…”

Section: Light-controlled Surface Wettabilitymentioning

confidence: 99%

Perspectives on oblique angle deposition of thin films: From fundamentals to devices

Barranco

Borrás

González‐Elipe

et al. 2016

Progress in Materials Science

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583

436

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a b s t r a c tThe oblique angle configuration has emerged as an invaluable tool for the deposition of nanostructured thin films. This review develops an up to date description of its principles, including the atomistic mechanisms governing film growth and nanostructuration possibilities, as well as a comprehensive description of the applications benefiting from its incorporation in actual devices. In contrast with other reviews on the subject, the electron beam assisted evaporation technique is analyzed along with other methods operating at oblique angles, including, among others, magnetron sputtering and pulsed laser or ion beam-assisted deposition techniques. To account for the existing differences between deposition in vacuum or in the presence of a plasma, mechanistic simulations are critically revised, discussing well-established paradigms such as the tangent or cosine rules, and proposing new models that explain the growth of tilted porous nanostructures. In the second part, we present an extensive description of applications wherein oblique-angle-deposited thin films are of relevance. From there, we proceed by considering the requirements of a large number of functional devices in which these films are currently being utilized (e.g., solar cells, Li batteries, electrochromic glasses, biomaterials, sensors, etc.), and subsequently describe how and why these nanostructured materials meet with these needs.

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“…Then, a ZnO shell is grown at room temperature using plasma-enhanced chemical vapour deposition in a remote configuration. The properties of CoPc/ZnO NWs depend strongly on the integrity of the organic core after the plasma deposition of the shell [26,27]. This property, along with the detailed morphology of the ZnO shell along the full NW, was investigated here by HAADF-STEM tomography.…”

Section: Methodsmentioning

confidence: 99%

Reduced-dose and high-speed acquisition strategies for multi-dimensional electron microscopy

Saghi

Benning

Leary

et al. 2015

Adv Struct Chem Imag

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Multi-dimensional electron microscopy has recently gained considerable interest thanks to the advent of microscopes with unprecedented analytical and in situ capabilities. These information-rich imaging modes, though, are often subject to long acquisition times and large data generation. In this paper, we explore novel acquisition strategies and reconstruction algorithms to retrieve reliable reconstructions from datasets that are limited in terms of both per image and tilt series angular sampling. We show that inpainting techniques are capable of restoring scanning transmission electron microscopy images in which a very restricted number of pixels are scanned, while compressed sensing tomographic reconstruction is capable of minimising artefacts due to angular subsampling. An example of robust reconstruction from data constituting a dose reduction of 10× is presented, using an organic/inorganic core-shell nanowire as a test sample. The combination of these novel acquisition schemes and image recovery strategies provides new avenues to reduced-dose and high-speed imaging.

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Vertically Aligned Hybrid Core/Shell Semiconductor Nanowires for Photonics Applications

Cited by 37 publications

References 58 publications

Self-Assembly of the Nonplanar Fe(III) Phthalocyanine Small-Molecule: Unraveling the Impact on the Magnetic Properties of Organic Nanowires

Self-Assembly of the Nonplanar Fe(III) Phthalocyanine Small-Molecule: Unraveling the Impact on the Magnetic Properties of Organic Nanowires

Perspectives on oblique angle deposition of thin films: From fundamentals to devices

Reduced-dose and high-speed acquisition strategies for multi-dimensional electron microscopy

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