scholarly journals Plasmonic nanostructures fabricated using nanosphere-lithography, soft-lithography and plasma etching

2011 ◽  
Vol 2 ◽  
pp. 448-458 ◽  
Author(s):  
Manuel R Gonçalves ◽  
Taron Makaryan ◽  
Fabian Enderle ◽  
Stefan Wiedemann ◽  
Alfred Plettl ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Soft Lithography ◽  
Low Cost ◽  
Nanosphere Lithography ◽  
Metal Films ◽  
Plasmonic Nanostructures ◽  
Gold Films ◽  
Spectral Position ◽  
Polystyrene Spheres ◽  
Plasmonic Structures

We present two routes for the fabrication of plasmonic structures based on nanosphere lithography templates. One route makes use of soft-lithography to obtain arrays of epoxy resin hemispheres, which, in a second step, can be coated by metal films. The second uses the hexagonal array of triangular structures, obtained by evaporation of a metal film on top of colloidal crystals, as a mask for reactive ion etching (RIE) of the substrate. In this way, the triangular patterns of the mask are transferred to the substrate through etched triangular pillars. Making an epoxy resin cast of the pillars, coated with metal films, allows us to invert the structure and obtain arrays of triangular holes within the metal. Both fabrication methods illustrate the preparation of large arrays of nanocavities within metal films at low cost. Gold films of different thicknesses were evaporated on top of hemispherical structures of epoxy resin with different radii, and the reflectance and transmittance were measured for optical wavelengths. Experimental results show that the reflectivity of coated hemispheres is lower than that of coated polystyrene spheres of the same size, for certain wavelength bands. The spectral position of these bands correlates with the size of the hemispheres. In contrast, etched structures on quartz coated with gold films exhibit low reflectance and transmittance values for all wavelengths measured. Low transmittance and reflectance indicate high absorbance, which can be utilized in experiments requiring light confinement.

Tailoring a periodic metal nanoantenna array using low cost template-assisted lithography

2019 ◽  
Vol 7 (44) ◽  
pp. 13818-13828 ◽  
Author(s):  
Adriano Colombelli ◽  
Daniela Lospinoso ◽  
Antonietta Taurino ◽  
Maria Grazia Manera
Keyword(s):  
Metal Nanoparticles ◽  
Low Cost ◽  
Nanosphere Lithography ◽  
Optical Response ◽  
Simple Approach ◽  
Plasmonic Nanostructures

Tailoring the optical response of metal nanoparticles by controlling their morphology is a key topic in the field of nano-optics. Here, a simple approach for the fabrication of tunable plasmonic nanostructures by nanosphere lithography is presented.

scholarly journals Synergic combination of the sol–gel method with dip coating for plasmonic devices

2015 ◽  
Vol 6 ◽  
pp. 500-507 ◽  
Author(s):  
Cristiana Figus ◽  
Maddalena Patrini ◽  
Francesco Floris ◽  
Lucia Fornasari ◽  
Paola Pellacani ◽  
...  
Keyword(s):  
Low Cost ◽  
Sol Gel ◽  
Silica Coating ◽  
Dip Coating ◽  
Fine Tuning ◽  
Plasmonic Nanostructures ◽  
Silica Layer ◽  
Surface Protection ◽  
Regeneration Time ◽  
Plasmonic Structures

Biosensing technologies based on plasmonic nanostructures have recently attracted significant attention due to their small dimensions, low-cost and high sensitivity but are often limited in terms of affinity, selectivity and stability. Consequently, several methods have been employed to functionalize plasmonic surfaces used for detection in order to increase their stability. Herein, a plasmonic surface was modified through a controlled, silica platform, which enables the improvement of the plasmonic-based sensor functionality. The key processing parameters that allow for the fine-tuning of the silica layer thickness on the plasmonic structure were studied. Control of the silica coating thickness was achieved through a combined approach involving sol–gel and dip-coating techniques. The silica films were characterized using spectroscopic ellipsometry, contact angle measurements, atomic force microscopy and dispersive spectroscopy. The effect of the use of silica layers on the optical properties of the plasmonic structures was evaluated. The obtained results show that the silica coating enables surface protection of the plasmonic structures, preserving their stability for an extended time and inducing a suitable reduction of the regeneration time of the chip.

scholarly journals Hole-mask colloidal nanolithography combined with tilted-angle-rotation evaporation: A versatile method for fabrication of low-cost and large-area complex plasmonic nanostructures and metamaterials

2014 ◽  
Vol 5 ◽  
pp. 577-586 ◽  
Author(s):  
Jun Zhao ◽  
Bettina Frank ◽  
Frank Neubrech ◽  
Chunjie Zhang ◽  
Paul V Braun ◽  
...  
Keyword(s):  
Composite Materials ◽  
Low Cost ◽  
Plasmonic Nanostructures ◽  
Large Area ◽  
Process Step ◽  
Plasmonic Structures ◽  
Chiral Structures ◽  
Angle Rotation ◽  
Optical Applications ◽  
Complex Nanostructures

Many nano-optical applications require a suitable nanofabrication technology. Hole-mask colloidal nanolithography has proven to be a low-cost and large-area alternative for the fabrication of complex plasmonic nanostructures as well as metamaterials. In this paper, we describe the fabrication process step by step. We manufacture a variety of different plasmonic structures ranging from simple nano-antennas over complex chiral structures to stacked composite materials for applications such as sensing. Additionally, we give details on the control of the nanostructure lateral density which allows for the multilayer-fabrication of complex nanostructures. In two accompanying movies, the fabrication strategy is explained and details are being demonstrated in the lab. The movies can be found at the website of Beilstein TV.

scholarly journals Interaction-tailored organization of large-area colloidal assemblies

2018 ◽  
Vol 9 ◽  
pp. 1582-1593 ◽  
Author(s):  
Silvia Rizzato ◽  
Elisabetta Primiceri ◽  
Anna Grazia Monteduro ◽  
Adriano Colombelli ◽  
Angelo Leo ◽  
...  
Keyword(s):  
Film Formation ◽  
Low Cost ◽  
Interparticle Distance ◽  
Particle Interactions ◽  
Polystyrene Spheres ◽  
Large Area ◽  
Nanoscale Patterning ◽  
Particle Solution ◽  
Number Of Particles ◽  
Deposition Conditions

Colloidal lithography is an innovative fabrication technique employing spherical, nanoscale crystals as a lithographic mask for the low cost realization of nanoscale patterning. The features of the resulting nanostructures are related to the particle size, deposition conditions and interactions involved. In this work, we studied the absorption of polystyrene spheres onto a substrate and discuss the effect of particle–substrate and particle–particle interactions on their organization. Depending on the nature and the strength of the interactions acting in the colloidal film formation, two different strategies were developed in order to control the number of particles on the surface and the interparticle distance, namely changing the salt concentration and absorption time in the particle solution. These approaches enabled the realization of large area (≈cm2) patterning of nanoscale holes (nanoholes) and nanoscale disks (nanodisks) of different sizes and materials.

scholarly journals Optical near-field mapping of plasmonic nanostructures prepared by nanosphere lithography

2018 ◽  
Vol 9 ◽  
pp. 1536-1543 ◽  
Author(s):  
Gitanjali Kolhatkar ◽  
Alexandre Merlen ◽  
Jiawei Zhang ◽  
Chahinez Dab ◽  
Gregory Q Wallace ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Hot Spots ◽  
Near Field ◽  
Nanosphere Lithography ◽  
Plasmonic Nanostructures ◽  
Far Field ◽  
Optical Images ◽  
Spatial Frequencies ◽  
Comparison Of The Results ◽  
Non Destructive

We introduce a simple, fast, efficient and non-destructive method to study the optical near-field properties of plasmonic nanotriangles prepared by nanosphere lithography. Using a rectangular Fourier filter on the blurred signal together with filtering of the lower spatial frequencies to remove the far-field contribution, the pure near-field contributions of the optical images were extracted. We performed measurements using two excitation wavelengths (532.1 nm and 632.8 nm) and two different polarizations. After the processing of the optical images, the distribution of hot spots can be correlated with the topography of the structures, as indicated by the presence of brighter spots at the apexes of the nanostructures. This technique is validated by comparison of the results to numerical simulations, where agreement is obtained, thereby confirming the near-field nature of the images. Our approach does not require any advanced equipment and we suggest that it could be applied to any type of sample, while keeping the measurement times reasonably short.

A Very Low-Cost, Labor-Efficient, and Simple Method to Block Scattered Ultraviolet Light in PDMS Microfluidic Devices by Inserting Aluminum Foil Strips

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuo Wang ◽  
Peter Shankles ◽  
Scott Retterer ◽  
Yong Tae Kang ◽  
Chang Kyoung Choi
Keyword(s):  
Soft Lithography ◽  
Uv Light ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Aluminum Foil ◽  
Material Synthesis ◽  
Simple Method ◽  
Micro Particles ◽  
Complex Shapes ◽  
The Cost

Abstract Opto-microfluidic methods have advantages for manufacturing complex shapes or structures of micro particles/hydrogels. Most of these microfluidic devices are made of polydimethylsiloxane (PDMS) by soft lithography because of its flexibility of designing and manufacturing. However, PDMS scatters ultraviolet (UV) light, which polymerizes the photocrosslinkable materials at undesirable locations and clogs the microfluidic devices. A fluorescent dye has previously been employed to absorb the scattered UV light and shift its wavelength to effectively solve this issue. However, this method is limited due to the cost of the materials (tens of dollars per microchip), the time consumed on synthesizing the fluorescent material and verifying its quality (two to three days). More importantly, significant expertise on material synthesis and characterization is required for users of the opto-microfluidic technique. The cost of preliminary testing on multiple iterations of different microfluidic chip designs would also be excessive. Alternatively, with a delicate microchannel design, we simply inserted aluminum foil strips (AFS) inside the PDMS device to block the scattered UV light. By using this method, the UV light was limited to the exposure region so that the opto-microfluidic device could consistently generate microgels longer than 6 h. This is a nearly cost- and labor-free method to solve this issue.

Investigation of the nonlinear refractive index of single-crystalline thin gold films and plasmonic nanostructures

2016 ◽  
Vol 122 (4) ◽  
Author(s):  
Sebastian Goetz ◽  
Gary Razinskas ◽  
Enno Krauss ◽  
Christian Dreher ◽  
Matthias Wurdack ◽  
...  
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Plasmonic Nanostructures ◽  
Gold Films ◽  
Single Crystalline

scholarly journals Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 387
Author(s):  
Carlos Toshiyuki Matsumi ◽  
Wilson José da Silva ◽  
Fábio Kurt Schneider ◽  
Joaquim Miguel Maia ◽  
Rigoberto E. M. Morales ◽  
...  
Keyword(s):  
Electric Fields ◽  
Microfluidic Device ◽  
Soft Lithography ◽  
Low Cost ◽  
Characteristic Curve ◽  
Microfluidic Devices ◽  
Average Diameter ◽  
Internal Diameter ◽  
Medical Diagnostic ◽  
Average Size

Microbubbles have various applications including their use as carrier agents for localized delivery of genes and drugs and in medical diagnostic imagery. Various techniques are used for the production of monodisperse microbubbles including the Gyratory, the coaxial electro-hydrodynamic atomization (CEHDA), the sonication methods, and the use of microfluidic devices. Some of these techniques require safety procedures during the application of intense electric fields (e.g., CEHDA) or soft lithography equipment for the production of microfluidic devices. This study presents a hybrid manufacturing process using micropipettes and 3D printing for the construction of a T-Junction microfluidic device resulting in simple and low cost generation of monodisperse microbubbles. In this work, microbubbles with an average size of 16.6 to 57.7 μm and a polydispersity index (PDI) between 0.47% and 1.06% were generated. When the device is used at higher bubble production rate, the average diameter was 42.8 μm with increased PDI of 3.13%. In addition, a second-order polynomial characteristic curve useful to estimate micropipette internal diameter necessary to generate a desired microbubble size is presented and a linear relationship between the ratio of gaseous and liquid phases flows and the ratio of microbubble and micropipette diameters (i.e., Qg/Ql and Db/Dp) was found.

scholarly journals Phenol Novalac Epoxy-modified unsaturated polyester hybrid networks by Silica Nanoparticles/ and Cross linking with Silane Compounds

2020 ◽  
Vol 1 (2) ◽  
pp. 28-32
Keyword(s):  
Epoxy Resin ◽  
Silica Nanoparticles ◽  
Elevated Temperatures ◽  
Unsaturated Polyester ◽  
Low Cost ◽  
Physical And Mechanical Properties ◽  
Hybrid Networks ◽  
Azo Compounds ◽  
Cross Linking ◽  
Chemical Attributes

In this study epoxy phenol novalac resin which consists of silica nanoparticles and unsaturated poly ester resin linked to the Silane and cross linking to that structure and also parameters affecting the processes involved have been evaluated. Cross linking in phenol novalac epoxy resins effects on many properties such as thermal, electrical, mechanical and chemical attributes especially in elevated temperatures. Silane cross-linking’s in phenol novalac epoxy resin with respect to other methods like proxiding, irradiation and utilization of Azo compounds, looks to be a very simple and low cost route, which makes it very encouraging for various industries. Unsaturated poly ester resin is compatible with phenol novalac epoxy resin and also creates some cross-linking and as far as tri methoxy Silane is added to the mentioned resin, its thermal, physical and mechanical properties are optimized. In this literature impact, tension, glass transition temperature, humidity absorption, FTIR and Scanning electron microscopy (SEM) tests were done and the results revealed that as the cross-linking occurs, tension in rupture region increases. This increase is more common at elevated temperatures. The growth in content of silica nanoparticles leads to a drop in water permeability of phenol novalac epoxy resin nanocomposite which contains unsaturated poly ester resin.

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