scholarly journals Generation of Core–Sheath Polymer Nanofibers by Pressurised Gyration

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1709 ◽  
Author(s):  
Suntharavathanan Mahalingam ◽  
Suguo Huo ◽  
Shervanthi Homer-Vanniasinkam ◽  
Mohan Edirisinghe
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Scale Up ◽  
Single Step ◽  
Water Soluble ◽  
Solid Core ◽  
Polymer Nanofibers ◽  
Working Pressure ◽  
Rotating Speed ◽  
Fibre Size

The ability to generate core–sheath bicomponent polymer nanofibers in a single-step with scale-up possibilities is demonstrated using pressurised gyration manufacturing. This is the first time that nanofiber containing more than one polymer having a core–sheath configuration has been generated in this way. Water-soluble polymers polyethylene oxide (PEO) and polyvinyl pyrrolidone (PVP) are used as the core and sheath layers, respectively. Core–sheath nanofibers with a diameter in the range of 331 to 998 nm were spun using 15 wt % PEO and 15 wt % PVP polymer solutions. The forming parameters, working pressure and rotating speed, had a significant influence on the size, size distribution and the surface morphology of the nanofibers generated. Overall, fibre size decreased with increasing working pressure and rotating speed. The fibre size was normally distributed in all cases, with 0.2 MPa working pressure in particular showing narrower distribution. The fibre size distributions for 0.1 and 0.3 MPa working pressure were broader and a mean fibre size of 331 nm was obtained in the latter case. The fibre size was evenly distributed and narrower for rotating speeds of 2000 and 4000 RPMs. The distribution was broader for rotating speed of 6000 RPM with a mean value obtained at 430 nm. Continuous, smooth and bead-free fibre morphologies were obtained in each case. The fibre cross-section analysis using a focused ion beam machine showed a solid core surrounded by a sheath layer. Our findings demonstrate that the pressurised gyration could be used to produce core–sheath polymer nanofibers reliably and cost-effectively with scale-up possibilities (~4 kg h−1).

Focused Ion Beam Analysis of Low-K Dielectrics

2000 ◽  
Author(s):  
H. J. Bender ◽  
R. A. Donaton
Keyword(s):  
Electron Microscope ◽  
Cross Section ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Single Step ◽  
Specimen Preparation ◽  
Transmission Electron ◽  
Beam Analysis ◽  
Low K ◽  
Scanning Electron

Abstract The characteristics of an organic low-k dielectric during investigation by focused ion beam (FIB) are discussed for the different FIB application modes: cross-section imaging, specimen preparation for transmission electron microscopy, and via milling for device modification. It is shown that the material is more stable under the ion beam than under the electron beam in the scanning electron microscope (SEM) or in the transmission electron microscope (TEM). The milling of the material by H2O vapor assistance is strongly enhanced. Also by applying XeF2 etching an enhanced milling rate can be obtained so that both the polymer layer and the intermediate oxides can be etched in a single step.

scholarly journals Thickness-modulated tungsten–carbon superconducting nanostructures grown by focused ion beam induced deposition for vortex pinning up to high magnetic fields

2016 ◽  
Vol 7 ◽  
pp. 1698-1708 ◽  
Author(s):  
Ismael García Serrano ◽  
Javier Sesé ◽  
Isabel Guillamón ◽  
Hermann Suderow ◽  
Sebastián Vieira ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Focused Ion Beam ◽  
Vortex Lattice ◽  
Ion Beam ◽  
Electrical Current ◽  
Single Step ◽  
Vortex Pinning ◽  
High Magnetic Fields ◽  
Pinning Potential ◽  
External Stimuli

We report efficient vortex pinning in thickness-modulated tungsten–carbon-based (W–C) nanostructures grown by focused ion beam induced deposition (FIBID). By using FIBID, W–C superconducting films have been created with thickness modulation properties exhibiting periodicity from 60 to 140 nm, leading to a strong pinning potential for the vortex lattice. This produces local minima in the resistivity up to high magnetic fields (2.2 T) in a broad temperature range due to commensurability effects between the pinning potential and the vortex lattice. The results show that the combination of single-step FIBID fabrication of superconducting nanostructures with built-in artificial pinning landscapes and the small intrinsic random pinning potential of this material produces strong periodic pinning potentials, maximizing the opportunities for the investigation of fundamental aspects in vortex science under changing external stimuli (e.g., temperature, magnetic field, electrical current).

Instant Solid Immersion Lens Creation in Silicon with a Focused Ion Beam – Comparing Refractive and Diffractive Methods

2011 ◽  
Author(s):  
P. Scholz ◽  
U. Kerst ◽  
C. Boit ◽  
T. Kujawa ◽  
T. Lundquist
Keyword(s):  
Processing Time ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Numerical Aperture ◽  
Single Step ◽  
Sample Thickness ◽  
Similar Process ◽  
Solid Immersion Lens ◽  
General Aspects

Abstract The theoretical fundamentals of diffractive solid immersion lenses (dSILs) were revised and adapted to a new application: the direct single-step chemistry-assisted creation of binary dSILs in silicon with a focused ion beam (FIB). Current results were able to prove the general functionality of this technique, but also showed the limitations still present. These limitations were identified; the underlying problems were analyzed and were addressed by optimizing several aspects of the process. The presented dSIL has a diameter of 150 ìm and is created in 15 minutes of processing time. It is designed for a sample thickness of 70 µm, which can be well adjusted if needed. For this sample thickness, the theoretical numerical aperture is about 2.5, offering a significant improvement in resolution. Furthermore a comparison of diffractive and refractive solid immersion lenses is presented, both created in a similar process. Apart from general aspects of dSILs and rSILs (refractive SILs), details of the designs presented in this work are compared. This leads to the insight of which method (dSIL or rSIL) has its advantages for which type of application.

Single-Step 3D Nanofabrication of Kinoform Optics via Gray-Scale Focused Ion Beam Lithography for Efficient X-Ray Focusing

2015 ◽  
Vol 3 (6) ◽  
pp. 792-800 ◽  
Author(s):  
Kahraman Keskinbora ◽  
Corinne Grévent ◽  
Michael Hirscher ◽  
Markus Weigand ◽  
Gisela Schütz
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Single Step ◽  
Gray Scale ◽  
X Ray ◽  
Ion Beam Lithography

scholarly journals Critical current modulation induced by an electric field in superconducting tungsten-carbon nanowires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pablo Orús ◽  
Vladimir M. Fomin ◽  
José María De Teresa ◽  
Rosa Córdoba
Keyword(s):  
Critical Temperature ◽  
Electric Field ◽  
Critical Current ◽  
Gate Voltage ◽  
Focused Ion Beam ◽  
Landau Theory ◽  
Ion Beam ◽  
Electrical Characterization ◽  
Single Step ◽  
Ginzburg Landau

AbstractThe critical current of a superconducting nanostructure can be suppressed by applying an electric field in its vicinity. This phenomenon is investigated throughout the fabrication and electrical characterization of superconducting tungsten-carbon (W-C) nanostructures grown by Ga$$^+$$ + focused ion beam induced deposition (FIBID). In a 45 nm-wide, 2.7 $$\upmu $$ μ m-long W-C nanowire, an increasing side-gate voltage is found to progressively reduce the critical current of the device, down to a full suppression of the superconducting state below its critical temperature. This modulation is accounted for by the squeezing of the superconducting current by the electric field within a theoretical model based on the Ginzburg–Landau theory, in agreement with experimental data. Compared to electron beam lithography or sputtering, the single-step FIBID approach provides with enhanced patterning flexibility and yields nanodevices with figures of merit comparable to those retrieved in other superconducting materials, including Ti, Nb, and Al. Exhibiting a higher critical temperature than most of other superconductors, in which this phenomenon has been observed, as well as a reduced critical value of the gate voltage required to fully suppress superconductivity, W-C deposits are strong candidates for the fabrication of nanodevices based on the electric field-induced superconductivity modulation.

Fabrication of Cost-Effective Polymer-Based Nanofluidic Device for Single Molecular Analysis

2010 ◽  
Author(s):  
Jiahao Wu ◽  
Rattikan Chantiwas ◽  
Steven A. Soper ◽  
Sunggook Park
Keyword(s):  
Focused Ion Beam ◽  
Low Cost ◽  
Ion Beam ◽  
Cost Effective ◽  
Single Step ◽  
Molecular Sensor ◽  
Sensor Structure ◽  
Nanofluidic Devices ◽  
Nanofluidic Device ◽  
Hierarchical Multiscale

A nanochannel based single molecular sensor was fabricated in poly(methyl methacrylate) substrate by a single step imprinting process with a polymer stamp. The sensor structure consists of hierarchical multiscale patterns of an array of 90 nm (depth) × 190 nm (width) × 80 μm (length) nanochannels and microfluidic networks. In contrast to nanofluidic devices fabricated by high-end nanofabrication tools such as focused ion beam milling and electron beam lithography, this direct imprint process is more desirable for efficient and low cost fabrication. Moreover, due to the reduction of stress generated during imprinting, this polymer stamp imprinting process can also reduce the deformation (warping) in molded substrates, and prevent the damage of expensive nanostructured stamp as well.

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