Search results for "dewetting"
showing 7 items of 17 documents
Programmable Surface Architectures Derived from Hybrid Polyoxometalate-Based Clusters
2011
The exploration of the self-organization of a range of the polyoxometalate-based molecular structures reveals a diverse range of surface patterns and morphologies on solid substrates of technological interest, including methylated and hydroxylated silicon surfaces (namely, SiCH3 and SiOH). By exploiting the interplay between the intrinsic molecular properties and the surface chemistry as well as dynamic spatiotemporal phenomena (e.g., dewetting), we show that these systems can yield 0D, 2D, and 3D architectures via solution deposition at the solid surface, including nanodots, discs, lamellas, porous networks, and layer-by-layer assemblies. In general, we observed that layer-by-layer growth …
Formation and Evolution of Nanoscale Metal Structures on ITO Surface by Nanosecond Laser Irradiations of Thin Au and Ag Films
2012
The effect of nanosecond laser irradiations on 5 nm thick sputter-deposited Au and Ag films on Indium-Tin-Oxide surface is investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). After 500, 750, and 1000 mJ/cm 2 fluence irradiations, the breakup of the Au and Ag films into nanoscale islands is observed as a consequence of fast melting and solidification processes. The mean nanoparticles size and surface density are quantified, as a function of the laser fluence, by the AFM and SEM analyses. In particular, the comparison between the Au and Ag islands reveals the formation of larger islands in the case of Ag for each fixed fluence. The mechanism of the nanoscale …
Light trapping by plasmonic nanoparticles
2020
Abstract Metallic nanoparticles sustaining localized surface plasmon resonances are of great interest for enhancing light trapping in thin film photovoltaics. In this chapter, we explore the correlation between the structural and optical properties of self-assembled silver nanostructures fabricated by a solid-state dewetting process on various substrates relevant for silicon photovoltaics and later integrated into plasmonic back reflectors. Our study allows us to optimize the performance of nanostructures by identifying the fabrication conditions in which desirable circular and uniformly spaced nanoparticles are obtained. Second, we introduce a novel optoelectronic spectroscopic method that…
Supra-aggregates of fiber-forming anisotropic molecules.
2006
In this paper, the self-organization of fiber-forming anisotropic molecules is inspected both theoretically and experimentally. In the first part, a theoretical model which extends the de Gennes theory of thin films to assemblies of strongly anisotropic molecules is reported. The model predicts that solid supported thin films made up of fiber-forming discotic molecules can grow with both tangential and radial arrangement of the fibers, respectively leading to the formation of compact and holed supra- aggregates. These last systems form according to the following picture. The tangential growth minimizes the number of unfavorable free ends but introduces elastic strain especially in the centr…
Temperature dependence of surface reorganization characteristics of amphiphilic block copolymer in air and in water studied by scanning force microsc…
2015
We have investigated the surface reorganization characteristics of a novel amphiphilic diblock copolymer, poly(acetic acid-2-(2-(4-vinyl-phenoxy)-ethoxy)-ethylester)-block-polystyrene (PAEES-b-PS), in response to varying interfaces from air to water and vice-versa at various temperatures. The surface reorganization characteristics of the block copolymer films was monitored by scanning force microscopy, in order to delineate the kinetically controlled morphological process of surface reorganization of a diblock copolymer, with a particular emphasis on the phase contrast signal which allowed the determination of local composition patterns of PAEES-b-PS at the surface. Upon heating a water-an…
On dewetting dynamics of solid films of hydrogen isotopes and its influence on tritium [Beta] spectroscopy
2000
The dewetting dynamics of solid films of hydrogen isotopes, quench-condensed on a graphite substrate, was measured at various temperatures below desorption by observing the stray light from the film. A schematic model describing the dewetting process by surface diffusion is presented, which agrees qualitatively with our data. The activation energies of different hydrogen isotopes for surface diffusion were determined. The time constant for dewetting of a quench-condensed T2 film at the working temperature of 1.86 K of the mainz neutrino mass experiment was extrapolated.
Rayleigh-instability-driven dewetting of thin Au and Ag films on indium-tin-oxide surface under nanosecond laser irradiations
2013
Investigations have been carried out on laser-beam-induced nanoparticle (NP) formation in thin (5 nm) Au and Ag films on indium-tin-oxide substrate. After the irradiation the films were observed to break-up into NPs through a dewetting mechanism. This mechanism was investigated as a Rayleigh-instability- driven process. In fact, for each used laser fluence, the resulting Au and Ag NPs' mean size and surface-to-surface mean distance were quantified and correlated between them in the framework of the Rayleigh-instability theory showing an excellent agreement. © The Institution of Engineering and Technology 2013.