Unconventional methods for forming nanopatterns

Stewart, Matthew E.; Motala, Michael J.; Yao, Jiang; Thompson, L. J.; Nuzzo, Ralph G.

doi:10.1243/17403499jnn103

Cited by 27 publications

(31 citation statements)

References 732 publications

(1,126 reference statements)

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“…Under these latter etching conditions, an effective channel length (L eff ) limit around 400 nm can be set while maintaining etching time, mask value (L mask ) and aspect ratio (vertical over lateral etch) around 2.25 min, 1 lm and 1:1, respectively. According to Stewart et al, 21 the lowest acceptable and realistic soft Sylgard 184 PDMS dimension lies around 1 lm. In this case, the latter parameters become 5.5 min and 2.5 lm for the same aspect ratio.…”

Section: Az1518 Versus Su-8mentioning

confidence: 97%

Molds and Resists Studies for Nanoimprint Lithography of Electrodes in Low-Voltage Polymer Thin-Film Transistors

Cavallari

Zanchin

Pojar

et al. 2014

Journal of Elec Materi

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A low-cost patterning of electrodes was investigated looking forward to replacing conventional photolithography for the processing of low-operating voltage polymeric thin-film transistors. Hard silicon, etched by sulfur hexafluoride and oxygen gas mixture, and flexible polydimethylsiloxane imprinting molds were studied through atomic force microscopy (AFM) and field emission gun scanning electron microscopy. The higher the concentration of oxygen in reactive ion etching, the lower the etch rate, sidewall angle, and surface roughness. A concentration around 30 % at 100 mTorr, 65 W and 70 sccm was demonstrated as adequate for submicrometric channels, presenting a reduced etch rate of 176 nm/min. Imprinting with positive photoresist AZ1518 was compared to negative SU-8 2002 by optical microscopy and AFM. Conformal results were obtained only with the last resist by hot embossing at 120°C and 1 kgf/cm 2 for 2 min, followed by a 10 min post-baking at 100°C. The patterning procedure was applied to define gold source and drain electrodes on oxide-covered substrates to produce bottom-gate bottom-contact transistors. Poly(3-hexylthiophene) (P3HT) devices were processed on high-j titanium oxynitride (TiO x N y ) deposited by radiofrequency magnetron sputtering over indium tin oxide-covered glass to achieve low-voltage operation. Hole mobility on micrometric imprinted channels may approach amorphous silicon ($0.01 cm 2 /V s) and, since these devices operated at less than 5 V, they are not only suitable for electronic applications but also as sensors in aqueous media.

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Section: Az1518 Versus Su-8mentioning

confidence: 97%

Molds and Resists Studies for Nanoimprint Lithography of Electrodes in Low-Voltage Polymer Thin-Film Transistors

Cavallari

Zanchin

Pojar

et al. 2014

Journal of Elec Materi

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“…Two approaches are commonly used for the preparation of plasmonic nanostructures: bottom-up and top-down34. The bottom-up approach involves the reduction of metal salts or assembly of nanoparticles in suspension or on the surface353637.…”

mentioning

confidence: 99%

Fabrication and Characterization of Flexible and Tunable Plasmonic Nanostructures

Kahraman

Daggumati

Kurtuluş

et al. 2013

Sci Rep

119

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We present a novel method to fabricate flexible and tunable plasmonic nanostructures based on combination of soft lithography and nanosphere lithography, and perform a comprehensive structural and optical characterization of these structures. Spherical latex particles are uniformly deposited on glass slides and used as molds for polydimethylsiloxane to obtain nanovoid structures. The diameter and depth of the nanostructures are controlled by the size of the latex particles. These surfaces are coated with a thin Ag layer for fabrication of uniform plasmonic nanostructures. Structural characterization of these surfaces is performed by SEM and AFM. Optical properties of these plasmonic nanostructures are evaluated via UV/Vis absorption spectroscopy, dark field microscopy, and surface–enhanced Raman spectroscopy (SERS). Position of the surface plasmon absorption depends on the diameter and depth of the nanostructures. SERS enhancement factor (measured up to 1.4 × 106) is dependent on the plasmon absorption wavelength and laser wavelength used in these experiments.

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“…37 Top-down fabrication techniques utilize different lithographic methods in order to produce patterned nanostructures whereas bottom-up methods are based on the assembly of atoms, molecules, and other components into nanostructures either on substrates or in solution. Top-down lithography methods, such as electron beam lithography, can produce plasmonic materials with great control over the size, shape, and spacing of metal nanostructures.…”

Section: Top-down Vs Bottom-upmentioning

confidence: 99%

Nanoplasmonic Sensing using Metal Nanoparticles

Martinsson¹

2014

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In our modern society, we are surrounded by numerous sensors, constantly feeding us information about our physical environment. From small, wearable sensors that monitor our physiological status to large satellites orbiting around the earth, detecting global changes. Although, the performance of these sensors have been significantly improved during the last decades there is still a demand for faster and more reliable sensing systems with improved sensitivity and selectivity. The rapid progress in nanofabrication techniques has made a profound impact for the development of small, novel sensors that enables miniaturization and integration. A specific area where nanostructures are especially attractive is biochemical sensing, where the exceptional properties of nanomaterials can be utilized in order to detect and analyze biomolecular interactions.The focus of this thesis is to investigate plasmonic nanoparticles composed of gold or silver and optimize their performance as signal transducers in optical biosensors. Metal nanoparticles exhibit unique optical properties due to excitation of localized surface plasmons, which makes them highly sensitive probes for detecting small, local changes in their surrounding environment, for instance the binding of a biomolecule to the nanoparticle surface. This is the basic principle behind nanoplasmonic sensing based on refractometric detection, a sensing scheme that offers real-time and label-free detection of molecular interactions.This thesis shows that the sensitivity for detecting local refractive index changes is highly dependent on the geometry of the metal nanoparticles, their interaction with neighboring particles and their chemical composition and functionalization. An increased knowledge about how these parameters affects the sensitivity is essential when developing nanoplasmonic sensing devices with high performance based on metal nanoparticles. VI VII Populärvetenskaplig sammanfattningI dagens samhälle finns en påtaglig vilja och strävan efter att kunna mäta, övervaka, analysera och reglera vardagliga funktioner och beteenden. Detta har lett till en explosionsartad utveckling av nya, funktionella sensorer som numera finns överallt i våra liv -i hemmet, på arbetsplatsen, i våra fickor och till och med inuti våra kroppar. En biosensor är en särskild typ av sensor som används för att detektera specifika kemiska eller biologiska ämnen genom att omvandla förekomsten av dessa ämnen till en mätbar signal. Biosensorer kan användas inom flera olika områden som livsmedelindustri, processövervakning, kriminalteknologi samt inom medicinsk diagnostik. Ofta är dock koncentrationen av de eftersökta ämnena mycket låg vilket ställer stora krav på sensorernas känslighet och precision.I denna avhandling beskrivs hur nanopartiklar av guld och silver kan användas som signalomvandlare i optiska biosensorer. Metalliska nanopartiklar har unika optiska egenskaper vilket gör dem väldigt känsliga mot små förändringar i dess absoluta närhet. Sådana förändringar ger upphov till en färgf...

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Unconventional methods for forming nanopatterns

Cited by 27 publications

References 732 publications

Molds and Resists Studies for Nanoimprint Lithography of Electrodes in Low-Voltage Polymer Thin-Film Transistors

Molds and Resists Studies for Nanoimprint Lithography of Electrodes in Low-Voltage Polymer Thin-Film Transistors

Fabrication and Characterization of Flexible and Tunable Plasmonic Nanostructures

Nanoplasmonic Sensing using Metal Nanoparticles

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