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This manuscript is dedicated to advancing the understanding of biomolecular film on solid target formation, with a particular emphasis on the intricacies of structure nonuniformities in amino acid and protein-based dehydrated films. Experimental and theoretical studying the structure of films at the quantitative level has been created and tested. By integrating advanced imaging and statistical analysis, we dissect the dynamics and intricacies of domain structures, including cellular and microcrystalline formations, that significantly influence dehydrated biomolecular film properties. The research process entails preparing amino acid and protein solutions, capturing high-resolution images during dehydration, and implementing advanced digital image processing techniques like Laplacian Pyramid Restoration and Gaussian Differential Scale-Invariance for enhanced image clarity. Analytical approach includes domain segmentation and texture analysis using Haralick features, enabling precise quantification of structural complexities in films formed under various dehydration conditions and protein concentrations. The suggested physical model describes the transition from equilibrium solutions through nonequilibrium processes to complex bubble vaporization, dehydration-induced Dewetting and domain differentiation, thus explained observed spiral formations within protein domains. This model provids a detailed mechanistic understanding of how environmental conditions and molecular dynamics drive the formation of domains, paving the way for developing films with tailored properties for diverse applications. These insights hold significant implications across various fields, including material science, nanotechnology, biomedical applications, environmental monitoring, electronics, and photonics. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the impact of various annealing schemes on the formation and agglomeration mechanisms of ultrathin Ni(Pt)Si films is investigated. To this end, 11 ± 1 nm-thick Ni(Pt)Si films are grown on 300 mm Si(100) wafers using various traditional rapid thermal annealing procedures as well as laser annealing. The obtained silicide films are then subjected to additional annealing between 500 and 800 °C, to evaluate their stability at high temperature. The correlation between the as-grown Ni(Pt)Si film properties and their capability to withstand agglomeration is analyzed via a complementary approach of several techniques (Rs, ellipsometry, TEM-EDX, SEM, and EBSD). Texture comparison for ultrathin films give deeper insights into the role of the NiSi-(010) and NiSi-(013) orientations in the agglomeration phenomenon. Depending on the annealing schemes used during the silicide formation, there is a strong correlation between the initial microstructure of Ni(Pt)Si films and their subsequent degradation. Indeed, cross-analysis of these different key parameters indicates that the presence of small Ni(Pt)Si grains (40 nm) obtained after laser annealing, and a high ratio of Ni(Pt)Si grains oriented along the (013) direction appears to be more efficient in delaying the agglomeration to higher temperatures. [ABSTRACT FROM AUTHOR]

Scalable production of carbon nanotubes (CNTs) requires catalysts and reaction conditions that provide high nucleation efficiency. In situ characterization methods such as environmental transmission electron microscopy (ETEM) can reveal fundamental mechanisms of synthesis, but to date have primarily provided qualitative observations on small sample sizes. Here, quantitative analysis is performed using high-resolution, high-rate video capture of ETEM experimentation coupled with automated image processing, involving computer vision algorithms and convolutional neural networks. By this approach, we detect distinct nanoparticle formation from an alumina-supported iron thin film and subsequent CNT nucleation from the nanoparticles. The statistical summary of particles in each video shows that, compared to a H 2 -only atmosphere, pretreatment of the catalyst with carbon added to the H 2 atmosphere results in a smaller average particle diameter, a 2-fold increase in particle density (to 5300 particles/ μ m2), a 3-fold increase in CNT nucleation efficiency (to 92 %), and more than a 5-fold increase in CNT density (to 4800/ μ m2). Addition of carbon during exposure to H 2 is also more effective than NH 3 at dewetting the catalyst film and increasing the CNT nucleation efficiency, in spite of NH 3 being a stronger reducing agent for iron. Insights from this study are applicable to improving CNT yield and productivity in both batch-style and continuous processes. [Display omitted] [ABSTRACT FROM AUTHOR]

Nepenthes pitcher plants grow in nutrient-poor soils and produce large pitfall traps to obtain additional nutrients from animal prey. Previous research has shown that the digestive secretion in N. rafflesiana is a sticky viscoelastic fluid that retains insects much more effectively than water, even after significant dilution. Although the retention of prey is known to depend on the fluid's physical properties, the details of how the fluid interacts with insect cuticle and how its sticky nature affects struggling insects are unclear. In this study, we investigated the mechanisms behind the efficient prey retention in N. rafflesiana pitcher fluid. By measuring the attractive forces on insect body parts moved in and out of test fluids, we show that it costs insects more energy to free themselves from pitcher fluid than from water. Moreover, both the maximum force and the energy required for retraction increased after the first contact with the pitcher fluid. We found that insects sink more easily into pitcher fluid than water and, accordingly, the surface tension of N. rafflesiana pitcher fluid was lower than that of water (60.2 vs. 72.3 mN/m). By analysing the pitcher fluid's wetting behaviour, we demonstrate that it strongly resists dewetting from all surfaces tested, leaving behind residual films and filaments that can facilitate re-wetting. This inhibition of dewetting may be a further consequence of the fluid's viscoelastic nature and likely represents a key mechanism underlying prey retention in Nepenthes pitcher plants. Carnivorous Nepenthes pitcher plants secrete sticky viscoelastic fluids that prevent insects from escaping after falling into the pitcher. What physical mechanisms are responsible for the fluid's retentive function? First, insects sink and drown more readily in N. rafflesiana pitcher fluid due to its reduced surface tension. Second, once within the fluid, our force measurements show that it costs more energy to separate insects from pitcher fluid than from water. Third, the fluid strongly resists dewetting, making it harder for insects to extract themselves and covering their cuticle with residues that facilitate re-wetting. Such striking inhibition of dewetting may represent a previously unrecognised mechanism of prey retention by Nepenthes. Pitcher fluid fulfils a well-defined biological function and may serve as a model for studying the mechanics of complex fluids. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, the dewetting process of an amorphous-Ge-based thin film (a-Ge) upon annealing has been studied, highlighting the morphological and structural properties of the dewetted islands. By a combination of in-situ reflection high-energy electron diffraction (RHEED) during low and high-temperature annealing and by electron back scatter diffraction (EBSD), the initial crystallization dynamics of the Ge film has been clarified, and the structural characterization of the dewetted islands has been disclosed by high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Chemical composition has been assessed by electron energy loss spectroscopy (EELS). Different initial a-Ge film thickness (range: 10 nm–200 nm) and annealing treatments, i.e. annealing temperature in the range between 600 °C–820 °C, and annealing time in a 5–120 min range, have been investigated to control the dewetting process. Finally, we extended the solid state dewetting process up to 20 cm wafers showing the possibility to tune particles size varying the initial a-Ge thickness of the deposited film, highlighting the scalability of the process. Beyond fundamental understanding of the a-Ge dewetting process, these results are relevant for the fabrication of large-scale hard masters for nanoimprinting lithography and novel photonic platforms fabricated via a scalable, lithography-free, CMOS-compatible process. [ABSTRACT FROM AUTHOR]

• Generation of hybrid gold-silver nanoparticles by nanosecond laser thermal heating of thin metal films on a glass surface is presented. • Localized surface plasmon resonance of nanoparticles can be tuned in the range of 400–530 nm by varying the ratio and order of the primary films. • Substrates with engineered nanoparticles can act as SERS substrates with a high enhancement factor using different excitation wavelengths. • The best results in SERS experiments were obtained using a lower wavelength laser (532 nm) as the excitation source. • The demonstrated laser-based process for large-scale production of SERS substrates is ordinary, reliable, chemical-free, and cost-effective. Generation of hybrid gold-silver nanoparticles from different metal ratios by thermal heating thin metal films on a glass surface with a nanosecond pulsed laser is presented. The optical properties of obtained nanoparticles are dependent on localized surface plasmon resonance (LSPR), which can be tuned in the range of 400–530 nm by varying the ratio and order of the primary films. The LSPR's width ranges from 40 nm to 130 nm. The various resonance widths suggest that different types of nanoparticles (monometallic or bimetallic alloy) with various concentrations and size distributions can be produced by laser-induced dewetting of thin bimetallic films. Substrates with engineered nanoparticles can act as SERS substrates with a high enhancement factor (more than 105) using different excitation wavelengths (532 and 633 nm). The best results in SERS experiments were obtained using a 532 nm excitation line. The enhancement factor directly depends on the size of the prepared nanoparticles. The demonstrated laser-based process for large-scale production of SERS substrates is ordinary, reliable, chemical-free, and cost-effective. [ABSTRACT FROM AUTHOR]

In the present work we introduce a simple approach to produce porous PtPdAg alloy nanoparticles on TiO 2 nanotubes by a simple combined sputtering-dewetting-dealloying process. In a first step, three individual metals (Pt, Pd and Ag) were sequentially sputter-deposited on spaced TiO 2 nanotubes, followed by a thermal dewetting treatment in Ar to convert these metal layers into ternary PtPdAg alloyed particles. Dealloying was carried out by a selective chemical dissolution of Ag in piranha solution that finally generated porous alloyed nanoparticles located on the TiO 2 nanotube walls. The porous PtPdAg-decorated TiO 2 nanotubes show enhanced photocatalytic H 2 generation in comparison with porous Pt (67% increase) or any monometallic decoration (>120% increase). The photocatalytic enhancement is not only due to the increased number of active sites (larger surface area) of the porous particles but also due to the synergistic effects of the different alloying elements. Image 1 • PtPdAg alloy particles were formed by sputtering-dewetting on TiO 2 nanotubes. • Porous alloy nanoparticles were produced through a selective chemical dissolution of Ag. • Porous alloy particles deliver higher H 2 generation than monometallic particles. • The high activity is due to a high surface area and synergistic elemental effects. [ABSTRACT FROM AUTHOR]

Thin metal films deposited on ceramic substrates tend to undergo dewetting (agglomeration) at elevated temperatures even in the solid state. We characterized the dewetting of 40 nm thick Ni films on sapphire in the temperatures range of 700–900 °C and explored the effect of a minor (below 1 at.%) Au doping on the dewetting kinetics. The Ni film was doped with Au in three different ways: by a uniform alloying, by depositing a Ni-Au-Ni trilayer, and by depositing a Au overlayer on the Ni film. We found that Au additions decrease the dewetting rate of Ni films and increase their stability at high temperatures. We discuss this phenomenon in terms of increase of surface anisotropy of Ni caused by surface segregation of Au. The increased anisotropy reduces the extent of thermal grooving at the grain boundaries and retards the formation of dewetting holes. The strongest retardation of dewetting was observed in Ni films with Au overlayer. We discuss this observation in terms of the dominance of the surface diffusion path in the dewetting process. • Minor alloying with gold delays the solid state dewetting of thin Ni films. • Gold segregates to the film surface and Ni-sapphire interface. • Surface segregation of gold increases surface energy anisotropy of Ni. • Increased surface anisotropy is responsible for the delay of dewetting. [ABSTRACT FROM AUTHOR]

We systematically investigated the morphological evolution of thin polymer blend films via annealing in mixed solvents. Here, a simple and efficient approach was proposed to fabricate different complex polymer nanostructures based on the dewetting of polymer blend films in mixed solvent. First, the nanobowl structures of poly(methyl methacrylate) and π-conjugated polymer-poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] were fabricated using this method. In addition, we also found that reversible dynamic transition among complex polymer structures could be achieved. This allowed us to reversibly adjust the complex structures by different external stimuli. Finally, it was determined that various arrays of complex polymer nanostructures, such as Janus nanostructures, core-shell nanostructures, nanobowls, nanochannels, and nanotubes, could be fabricated by pre-patterning the thin polymer blend films. The dewetting of polymer blend film in the mixed solvent provides a simple and efficient self-assembly approach for fabricating arrays of different complex polymer nanostructures. Image 104 • The nanobowl structures of PMMA and MEH-PPV are prepared via a simple dewetting method. • The polymer complex structures can be reversibly adjusted. • Various arrays of complex polymer nanostructures are fabricated by pre-patterning the thin polymer blend films. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ag and Au films on glass and Si substrates are dewetted into nanoparticles by a single nanosecond laser pulse. • The pulse energy densities required for dewetting are theoretically derived and compared with the experimental values. • A larger film area is laser-dewettable when the substrate has poorer thermal conduction. Abstract This article studies the effects of film and substrate on the laser-induced dewetting of metal thin films. Ag and Au films, both 10 nm in thickness, were deposited onto glass and Si substrates and dewetted using a single pulse from a nanosecond-pulsed Nd:YAG laser at λ = 1,064 nm. The Ag film was completely dewetted into nanoparticles at a pulse energy density of about 70 mJ/cm2 on the glass substrate while an energy density over 390 mJ/cm2 was needed for the Si substrate. This is attributed to the fact that Si has a much higher thermal conductivity than glass and that the laser energy absorbed by the film significantly dissipated into the Si substrate rather than being solely used to heat the film. The Au film required slightly more laser energy in comparison to the Ag film. The energy densities of a laser pulse required to dewet the Ag and Au films were theoretically derived using one-dimensional heat conduction equations and thermodynamic data. The difference between the experimental and calculated pulse energies was more significant for the Si substrate. This indicates that lateral thermal diffusion occurred considerably on the Si substrate even with a nanosecond pulse duration. We demonstrate both experimentally and theoretically that as the thermal conductivity of the substrate increases, the film area dewettable by a laser pulse is decreased. [ABSTRACT FROM AUTHOR]

We investigated dynamical processes of capillary-mediated deformation of vertically aligned single-walled carbon nanotubes (VA-SWCNTs) via in situ observation of their wetting and dewetting behaviors using an environmental scanning electron microscope (ESEM). Three types of wetting behaviors on a VA-SWCNT sample were confirmed, including conical shaped water aggregates, spherical droplets on tips of conical shaped water aggregates, and extensively distributed water layers. While the former two types both resulted in dimples on the VA-SWCNT surface and failed to induce large-scale deformation of VA-SWCNTs, the latter caused the formation of wall-like structures and crack propagation in the VA-SWCNT film during the dewetting process due to directional retraction of vapor-liquid interfaces. This dewetting-induced large-scale deformation that was confirmed by the in situ ESEM observation for the first time represented initial stages of capillary processes, leading to the self-organization of VA-SWCNTs reported in recent literatures. Compared to the previous studies based on ex situ observations of dried samples, our in situ observation successfully captured temporal evolution of the dewetting-induced deformation, facilitating the more precise construction of predictive models of final morphologies of VA-SWCNT films after capillary-mediated densification. Unlabelled Image • In situ observation of dewetting-induced deformation of VA-SWCNTs was conducted. • ESEM observation captured dynamical processes of capillary-mediated deformation. • Three types of wetting behaviors on a VA-SWCNT sample were confirmed. • Directional retraction of vapor-liquid interfaces induced large-scale deformation. [ABSTRACT FROM AUTHOR]

Abstract During the operation of Solid Oxide Cell (SOC) fuel electrodes, the mobility of nickel can lead to significant changes in electrode morphology, with accompanying degradation in electrochemical performance. In this work, the dewetting of nickel films supported on yttria-stabilized zirconia (YSZ), hereafter called 2D cells, is studied by coupling in-situ environmental scanning electron microscopy (E-SEM), image analysis, cellular automata simulation and electrochemical impedance spectroscopy (EIS). Analysis of experimental E-SEM images shows that Ni dewetting causes an increase in active triple phase boundary (aTPB) length up to a maximum, after which a sharp decrease in aTPB occurs due to Ni de-percolation. This microstructural evolution is consistent with the EIS response, which shows a minimum in polarization resistance followed by a rapid electrochemical degradation. These results reveal that neither evaporation-condensation nor surface diffusion of Ni are the main mechanisms of dewetting at 560–800 °C. Rather, the energy barrier for pore nucleation within the dense Ni film appears to be the most important factor. This sheds light on the relevant mechanisms and interfaces that must be controlled to reduce the electrochemical degradation of SOC electrodes induced by Ni dewetting. Graphical abstract Image 1 Highlights • Nickel dewetting is analyzed with in-situ microscopy and modeling tools. • Microstructural evolution quantitatively matches the electrochemical response. • A maximum of three-phase boundary is identified before de-percolation starts. • Neither evaporation-condensation nor surface diffusion can explain Ni dewetting. [ABSTRACT FROM AUTHOR]

Graphical abstract Wetting transition and controllable coalescence dynamics can be achieved by subjecting the substrate to vibrating. Highlights • Vibration-induced wetting transition is investigated. • Well-wetting, weak-wetting and dewetting states can be switched. • A theoretical model to interpret wetting transition is established. • Vibration-induced wettability transition can control the coalescence. Abstract Controllable wettability of liquids has always been attached great significance to a wide range of applications in both industrial and technological processes. Here, we report a simple and novel approach to achieve reversible and switchable wettability through the vibration of substrate. Results showed that with the increase of the vibration frequency (f), the wetting state of the liquid metal gradually transform into wetting/dewetting mixed state, and finally becomes complete dewetting state. More importantly, on the basis of our established model (involving vibration amplitude, liquid-substrate interaction), we further interpret and predict the wetting status and the wetting transition procedure of the given droplet. Additionally, the vibration-induced wettability transition can be applied to control the coalescence dynamics, which generates three patterns: free-coalescence, semifree-coalescence, restricted-coalescence. Our work would develop a new strategy to control the surface wettability by vibrating the substrate, without any mechanical or chemical modifications, which could provide guidance in the manipulation of drop dynamics. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Silver nanoparticle arrays were produced via laser-induced dewetting of silver paste. • The first laser scan produced intermediate silver nanostructures. • The second laser scan transformed the intermediate structures into the arrays. • Silver nanoparticle arrays generated numerous hot spots to show strong SERS signals. • Our fabrication method of laser-induced dewetting is facile and scalable. Abstract Highly dense plasmonic silver nanoparticle (NP) arrays have been fabricated by laser-induced dewetting of commercially available silver paste as a starting bulk material. Laser-irradiation criteria for the laser melting, dewetting, and ablation of silver paste films have been determined in order to understand the optimal conditions of laser fabrication. The first laser-scan mode has produced unprecedented intermediate structures, so called laser-induced fine silver nanostructures (LIFSNs) while the second laser-scan mode has transformed LIFSNs into plasmonic silver NP arrays via the dewetting of the priorly formed nanostructures. The laser-induced fabrication of silver NP arrays has been found to be very sensitive to distance from secondly irradiated laser pulses, suggesting that the fine control of laser intensity is very important. Silver NP arrays of sub-100 nm diameters with narrow size distribution have been fabricated well at a laser scanning rate of ≥50 μm/s. As-prepared silver NP arrays have generated numerous hot spots to show highly strong surface-enhanced Raman scattering signals; the Raman enhancement factor of silver NP arrays for rhodamine 6G has been found as 1.2 × 106. Overall, our fabrication method of plasmonic silver NP arrays via laser-induced dewetting is facile, scalable, and reproducible. [ABSTRACT FROM AUTHOR]

Abstract Silicon (Si) has been the most widely used semiconductor for decades, playing an important role in the field of electronics, energy conversion and energy storage. Because of their unique morphological energy band characteristics, Si nanostructures exhibit superior performance in many applications in comparison with their bulk counterparts. In this study, the effects of thermal annealing on elemental composition and morphological properties of palladium metal thin films grown on c-Si substrates were investigated. Palladium (Pd) thin films of different thicknesses were deposited on Si (1 0 0) with and without native oxide layers by electron beam evaporation and annealed in vacuum at 600 °C for two hours. Scanning electron microscopy (SEM) studies have shown that the surface morphology showed an effective dewetting in individual droplets and islands which further coalesce into bigger islands. Rutherford backscattering spectrometry (RBS) and electrical measurements analyses revealed the diffusion of the Si substrate into the Pd layer during annealing. This contribution will discuss the effects of the metal layer thickness as well as the native oxide on the metal thin films. [ABSTRACT FROM AUTHOR]

Abstract In this work we studied the influence of Cr, as well as Fe combined with Cr, on the thermodynamics and structural characteristics of equilibrated interfaces between Ni and the (111) surface of yttrium stabilized ZrO 2 (YSZ). Ni particles were doped with Cr, or with Fe and Cr. Chemical analysis of the interfaces was conducted using energy dispersive spectroscopy (EDS) in scanning transmission electron microscopy (STEM), and the equilibrium crystal shapes (ECS) were simulated using the "Wulffmaker" software. Cr was found to adsorb to the Ni-YSZ interface, and in parallel to create a Cr 2 O 3 phase which partially wets the interface. The presence of Fe in solution in the Ni was found to reduce the amount of adsorption to the interface and prevent formation of Cr 2 O 3. Furthermore, in both doped systems, the same orientation relationship as in the un-doped system was found, regardless of the significant change in the equilibrium crystal shape. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract Dewetting or agglomeration is a crucial process in material science since it controls the stability of thin films or can be used for film nanostructuration by formation of islands. The models developed for dewetting usually assume diffusion at the interface and/or at the surface but no direct evidence of such diffusion was demonstrated. Moreover, these models are usually dealing with elemental materials and not with compounds in which several elements can diffuse. The mechanisms behind agglomeration of polycrystalline compound thin films are still not fully understood. In this work, Si isotope multilayers coupled with atom probe tomography (APT) are used to reveal the agglomeration mechanism of NiSi, a binary compound. The diffusion of Si, the less mobile species in NiSi, at the NiSi/Si interface is demonstrated through comparison between the three dimension redistribution of the Si isotopes determined by APT and models taking into account grooving and agglomeration. The implication for the understanding and control of agglomeration in polycrystalline compound thin films are highlighted. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A thin layer of gold was coated on an aluminum dimple array and then heated. • The gold layer was transformed into numerous gold particles by the thermal treatment. • The transformation rate increases with the temperature of the thermal treatment. • Multiply-twinned particles were distributed on the surface. • The gold particle array exhibited excellent adhesion properties. Abstract Gold nanoparticles were fabricated on an ordered aluminum dimple array via aluminum anodizing, sputter coating, and thermal treatment, and the transformation behavior and nanostructural characterization were investigated in detail. Electropolished aluminum specimens were anodized in an oxalic acid solution under self-ordering conditions at 40 V, and then the porous alumina was selectively dissolved to expose an ordered aluminum dimple array with each dimple measuring 100 nm. A thin layer of gold was coated onto the dimple array, and a thermal treatment was subsequently performed. The gold layer was transformed into numerous particles by the thermal treatment due to dewetting. When the values of gold layer thickness, thermal treatment temperature, and thermal treatment duration were optimized, the gold particles were located at the bottom of each aluminum dimple. Consequently, multiply-twinned particles with polygonal and elliptical shapes were regularly distributed on the aluminum dimple array treated at 473 K. Although the rate of the transformation induced by dewetting increased with the temperature of the thermal treatment, non-uniform gold nanostructures were formed by extended thermal treatment at 873 K. The gold particles formed on the aluminum surface exhibited excellent adhesion upon ultrasonication. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu@Ag particles were surface-treated by wet process using types of dicarboxylic acids. • SEM, UV–vis, FT-IR, Raman spectroscopy, XPS, and TG-DTA analysis verified treatment. • PA-modified particles exhibited delayed Ag dewetting and the most suppressed oxidation. • Formed film exhibited excellent electrical conductivity after sintering for just 1 min at 300 °C. • The surface treatment is a novel method for improving Ag sintering between Cu@Ag particles. A resin-free paste containing 1.5 μm Cu@Ag particles was fabricated and used to form a film with excellent electrical conductivity even after a significantly high-speed sintering process. The particle surfaces were treated using three types of dicarboxylic acids, namely OA, SA, and PA, with carboxyl groups to suppress the dewetting behavior of Ag shells generated during thermal sintering. SEM, UV–vis, FT-IR, Raman spectroscopy, XPS, and TG-DTA analysis were performed to verify the morphological changes, chemical binding states (formation of an organo-metallic surface), and thermal behavior changes on the particle surfaces after surface treatment. The PA-modified particle surface exhibited a delayed dewetting behavior and the most suppressed oxidation degree. Furthermore, the paste containing the surface-modified particles exhibited a significantly low electrical resistivity (5.05 × 10−6 Ω·cm) after sintering for just 1 min at 300 °C under N 2 , which is an improvement of approximately three orders of magnitude over the original paste. Consequently, the surface treatment using effective dicarboxylic acid, which simultaneously inhibited Ag dewetting and suppressed Cu oxidation, improved Ag sintering between particles and enhanced the electrical properties of the sintered film. [ABSTRACT FROM AUTHOR]

[Display omitted] • Block copolymer stamps were used for the additive and subtractive generation of topographic surface patterns taking advantage of specific block copolymer properties. • Additive surface patterning with breath figure array top layers was achieved by decal transfer microlithography using bottom-up block copolymer stamps obtained by the breath figure method. • The wettability of surfaces functionalized with breath figure array top layers consisting of block copolymers was switched by treatments with solvents selective to the block segments. • Perfluorinated alkylphosphonate patterns for subtractive surface patterning were deposited on silica glass with spongy-mesoporous block copolymer stamps. • The perfluorinated alkylphosphonate patterns were used as etch resists for direct wet etching of glass or to guide the dewetting of polymer droplets used as etch resists. We explore the potential of stamps of the block copolymer (BCP) polystyrene- block -poly (2-vinylpyridine) (PS- b -P2VP) for the parallel lithographic generation of topographic surface patterns taking advantage of the specific BCP properties. A first example includes additive surface manufacturing by decal transfer microcontact lithography with PS- b -P2VP breath figure (BF) arrays. Suppression of entanglements at the internal BCP domain interfaces and the BF array morphology facilitate rupture of the thinnest wall segments in the BF arrays. The uppermost PS- b -P2VP BF array layers with heights of nearly 1 µm thus remained attached to counterpart substrates. Treatment with solvents selective to PS or P2VP enabled wettability switching of thus-functionalized surfaces. A second example includes subtractive surface manufacturing. We deposited holey films or stripe patterns of the perfluorinated alkylphosphonic acid F 21 -DDPA on glass substrates using PS- b -P2VP stamps penetrated by spongy mesopore systems generated by swelling-induced pore formation. The use of spongy-mesoporous stamps allows carrying out succesive stamping steps without ink replenishment. Subsequently, we topographically patterned the glass substrates by etching the parts of the glass substrates not protected by F 21 -DDPA with hydrofluoric acid (HF) solution. Within certain limitations, shape, area and depth of the topographic patterns may be adjusted by the etching durations. Circular PS- b -P2VP films were selectively deposited into hexagonal microwells and subjected to swelling-induced pore formation. Moreover, F 21 -DDPA-patterned glass substrates can be used to template the dewetting of polystyrene (PS). Arrays of PS droplets obtained in this way were in turn used as etch resists to produce arrays of glass nanoneedles. Hence, BCP stamps may be exploited to produce topographically patterned surfaces with different architectures for wettability management or graphoepitaxy. [ABSTRACT FROM AUTHOR]

Experiments and computer simulations of bicrystals have been extensively used to study the role of thermal grooving on grain boundary motion. Although these studies provide a fundamental understanding of the factors that affect boundary motion, they do not capture interactions between the grain boundary network and (solid-vapor) surface on the overall grain growth kinetics. To understand the complex interactions between the thermal groove and the grain boundary, we developed a three-dimensional phase-field model to simulate concurrent capillary-driven grain growth and surface diffusion-controlled thermal grooving. We systematically studied the role of film thickness and surface diffusivity on the interactions between thermal grooving and grain growth in polycrystalline films. To make outcomes statistically significant, we implement an efficient active parameter tracking algorithm that can simulate a large number of grain orientations. Our results show an increase in the degree of stagnation with the reduction in film thickness due to the modification of boundary curvature normal to the surface of the film. Large-scale simulations of polycrystalline films show the development of nonuniform groove surface profiles with varying degrees of asymmetry that correspond to steady state, decelerating, and stationary boundaries. The stagnation of grain boundaries shows dependence on groove depth and topological distribution of grains. The critical grain size for grain boundary stagnation and grain size distribution varies with film thickness. We also demonstrate, using various tailored configurations, how concomitant thermal grooving can lead to the complete arrest of grain growth. [Display omitted] [ABSTRACT FROM AUTHOR]

Wetting of solid surfaces by liquid deposition, contact dispensing, drop transfer, collision of wet particles, or during coating processes is often accompanied by the formation of liquid bridges between two or more solid substrates. They appear in many applications, like material science, microfluidics, biomedical, chemical, or aerospace engineering, and different fields of physics. In this study, the flows accompanying lifting of a Hele-Shaw cell, stretching or shearing of a liquid bridge, as well as liquid bridge flows observed during printing processes and other important applications, are briefly reviewed. Such flows are governed by surface tension, inertia, stresses associated with the liquid rheology, and forces caused by the substrate's wettability. Instabilities of liquid bridges lead to the formation of finger-like structures on the substrate or the appearance of cavities at the wetted region of the wall. The time required for jet pinch-off also determines the residual liquid volume on both solid bodies. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The formation of submicron polystyrene (PS) particles based on dewetting process during spin-coating was investigated. The surface morphologies on glass substrates were analyzed. The formation of particles was achieved using PS with relatively high molecular weight (Mw ≥ 3250). In addition, it was observed that the particle formation proceeded through sequential morphological changes in the order of initial wet thin film, secondary spinodal-decomposed structures, and eventual dewetted particles. One of the fabricated samples exhibited obvious optical resonance in the visible region based on the relationship between particle dimeters and optical wavelengths in the visible region. The optical resonance strongly depended on the ambient refractive index, which can be used for optical sensor-chips. Finally, a multi-functional biosensor-chip was demonstrated to detect glucose in water solutions. [ABSTRACT FROM AUTHOR]

We report on the anti-reflection characteristics of silica nanopillars fabricated using bimetallic copper-silver nanoparticles as an etch mask. The particles were formed by dewetting and their size and shape were controlled by the film thickness and annealing conditions. Our results showed that annealing of a copper-silver film results in formation of segregated bimetallic nanoparticles. Using these bimetallic nanoparticles as a mask for reactive ion etching produced dual diameter nanopillars, compared to single diameter nanopillars for monometallic nanoparticles. The height and shape of the nanopillars were controlled by the initial film thickness, annealing temperature, and etching parameters. The fabricated silica nanopillars showed a reduction in reflectance as compared to the bare substrate in the UV–Vis-NIR range, and dual diameter nanopillars were better as compared to single diameter nanopillars. Increasing etch duration resulted in increase in pillar height and a further reduction in reflectance. These silica nanopillar structures can be used as anti-reflection coatings. [ABSTRACT FROM AUTHOR]

Quadrupolar plasmon resonances that originate from interparticle near-field coupling interaction were observed in arrays composed of small-sized Ag nanoparticles (∼30 nm). The arrays were prepared by a dewetting process, during which hexagonally arranged aluminum pits were used to induce and confine the nucleation and growth of Ag nanoparticles. With the increase in the thickness of the initial Ag film, the particle size increases, and the interparticle spacing decreases to sub-10 nm scale, making adjacent particles strongly coupled. As a result, the quadrupolar resonance mode occurs, and its wavelength remains practically unchanged, while the dipolar mode shifts toward to a longer wavelength by about 80 nm. In comparison, only a dipolar resonance mode was observed in the non-coupled array that has a large interparticle spacing. The coupled array was demonstrated to exhibit much stronger surface enhanced Raman scattering (SERS) activity than that of the non-coupled array, suggesting that the quadrupolar mode can also be viewed as an indication of strong SERS enhancement in arrays composed of small-sized metal nanoparticles. [ABSTRACT FROM AUTHOR]

We highlight some recent developments that widen the scope and reach of mesoscopic thin-film (or long-wave) hydrodynamic models employed to describe the dynamics of thin films, drops and contact lines of simple and complex liquids on solid substrates. The basis of the discussed developments is the reformulation of various mesoscopic thin-film hydrodynamic models as gradient dynamics on underlying energy functionals. After briefly presenting the general approach, the following sections discuss how to improve these models by amending the energy functional and the mobility function, how to obtain gradient dynamics models for some complex liquids, and how to incorporate processes beyond relaxational dynamics. [ABSTRACT FROM AUTHOR]

In the present work, we report on the charge trapping properties of Germanium Nanocrystals (Ge NCs) self assembled on SiO 2 thin layer for promising applications in next-generation non volatile memory by the means of Deep Level Transient Spectroscopy (DLTS) and high frequency C-V method. The Ge NCs were grown via dewetting phenomenon at solid state by Ultra-High Vacuum (UHV) annealing and passivated with silicon before SiO 2 capping. The role of the surface passivation is to reduce the electrical defect density at the Ge NCs-SiO 2 interface. The presence of the Ge NCs in the oxide of the MOS capacitors strongly affects the C-V characteristics and increases the accumulation capacitance, causes a negative flat band voltage (V FB ) shift. The DLTS has been used to study the individual Ge NCs as a single point deep level defect in the oxide. DLTS reveals two main features: the first electron traps around 255 K could correspond to dangling bonds at the Si/SiO 2 interface and the second, at high-temperature (>300 K) response, could be originated from minority carrier generation in Ge NCs. [ABSTRACT FROM AUTHOR]

It is challenging to achieve long-lasting hydrophilicity by surface modification of polydimethylsiloxane (PDMS), principally due to the hydrophobic recovery that occurs. This involves the migration of low molecular weight species from the bulk to the surface and is driven by the reduction of interfacial free energy. In this study, spontaneous adsorption of poly(vinyl alcohol) was carried out on Sylgard PDMS films and their modified derivatives. PDMS ox1s , PDMS ox60s , and PDMS ox60s+2k were prepared by 1-s oxygen plasma, 60-s oxygen plasma, and 60-s oxygen plasma followed by covalent attachment of linear PDMS of 2 kDa molecular weight on PDMS films, respectively. Surface morphology was characterized by optical and atomic force microscopy and hydrophilicity was monitored by dynamic water contact angle measurements. It was found that negligible PVOH adsorption takes place on PDMS ox60s due to the lack of hydrophobic driving force and that extensive PVOH thin film dewetting on PDMS and PDMS ox1s results in insignificant improvement in hydrophilicity. However, a continuous PVOH thin film albeit with some small holes was obtained on PDMS ox60s+2k . PDMS ox60s+2k -PVOH exhibits advancing and receding contact angles of 80–90°/16 ± 2°, which are significantly lower than 123 ± 5°/97 ± 2° on unmodified PDMS. A range of static contact angles were also measured, some of which are lower than those reported in the literature. The PDMS ox60s+2k -PVOH system demonstrates superior long-term and hydrolytic stability, which are attributed to the removal of the driving force for hydrophobic recovery by inserting a hydrophobic PDMS layer between a hydrophilic, plasma-oxidized, PDMS bulk and a hydrophilic PVOH exterior. This is a new concept in addressing hydrophobic recovery of hydrophilized silicones. The spontaneous nature of the adsorption process and the crystallinity of the PVOH barrier layer are the other advantages demonstrated in this study. [ABSTRACT FROM AUTHOR]

The influences of a Ti seed layer (1 nm) on the dewetting phenomenon of Au films (5 nm) grown onto amorphous SiO 2 substrates have been studied and compared. Atomic force microscopy results indicated that the introduction of Ti between the substrate and Au promoted the dewetting phenomenon. X-ray diffraction measurements suggested that the initial deposition of Ti promoted crystallinity of Au. A series of Auger electron spectroscopy and X-ray photoelectron spectroscopy results revealed that Ti transformed to a Ti oxide layer by reduction of the amorphous SiO 2 substrate surface, and that the Ti seed layer remained on the substrate, without going through the dewetting process during annealing. We concluded that the enhancement of Au dewetting and the improvement in crystallinity of Au by the insertion of Ti could be attributed to the fact that Au location was changed from the surface of the amorphous SiO 2 substrate to that of the Ti oxide layer. [ABSTRACT FROM AUTHOR]

We studied the process of Au whiskers formation from Au thin films deposited on the glass substrate and covered with a conform passivating alumina layer. We demonstrated that the film thickness and morphology play an important role in whiskers formation. Annealing of 10 nm thick Au film exhibiting the discontinuous, maze-like morphology resulted in the formation of Au whiskers. Straight gold whiskers of up to 25 μm in length with a constant diameter were obtained after annealing at the temperatures above 800 °C. The grown whiskers exhibited dislocation-free microstructure. Annealing of 20 nm thick passivated Au film exhibiting continuous morphology resulted in the constrained dewetting of the Au film underneath the alumina layer, and did not lead to the growth of whiskers. We proposed that the main driving force for the whiskers growth is the replacement of the Au/alumina and Au/glass interfaces by one alumina/glass interface of lower energy. We have developed a kinetic model of whiskers growth controlled by the diffusion of gold atoms along the Au/glass and Au/alumina interfaces. The estimated diffusivity was close to the self-diffusion coefficient on the surface of Au. We demonstrated that Au nanoparticles attached to the alumina layer could be easily stripped off from the glass substrate using ethanol. [ABSTRACT FROM AUTHOR]

We here show that Ag-Au bimetallic nanoparticles (NPs) can be produced by dewetting an Ag/Au bilayer film coated on glass using a nanosecond-pulsed laser beam. Elemental analysis revealed that the obtained bimetallic NPs are Ag-Au alloys, with two elements well mixed over the whole volume of the particle. The composition of the produced particles was controllable by changing the relative thickness of each layer. The localized surface plasmon resonance (LSPR) peak was red-shifted with an increasing Au content and the LSPR wavelength could be tuned from 415 to 525 nm by varying the alloy composition. A film area of several square centimeters could be transformed into Ag-Au NPs by a single laser pulse of 6 ns duration. This study provides a facile and scalable route to prepare bimetallic NPs for plasmonic and other applications. [ABSTRACT FROM AUTHOR]

Long-term thermal stability of nickel line patterns was investigated. 5 μm-wide patterns and 20 μm-wide patterns were deposited with four different thicknesses, and their morphological change was compared after heat treatment. Displaced volume was calculated by post-annealing image analysis. Opposite coarsening trends were found for the two tested widths. 20 μm-wide patterns show deviation from predictions of previous models, but they still behave as expected: thinner pattern shows higher mobility. This is reversed for 5 μm-wide patterns. Surface tension at the metal-gas interface, the usual driving force behind coarsening, can still explain the unexpected displaced volume dependence on thickness. [ABSTRACT FROM AUTHOR]

A comparison between dewetting properties of amorphous Ge and GeMn layers on SiO 2 , followed by a detailed study of magnetic and structural properties of GeMn nanocrystals (NCs), is done by means of several characterization techniques. The formation of three-dimensional Ge and GeMn NCs by solid-state dewetting process was evidenced by transmission electron microscopy. Studying the dewetting morphologies revealed a weak dependence on the Mn content. We show that the size of the dewetted NCs is proportional to the initial film thickness. SQUID measurements of GeMn NCs show the ferromagnetic behavior of Mn 5 Ge 3 phase with Curie temperature at 300 K. Raman spectroscopy was performed for GeMn self-assembled NCs in order to investigate the effects of Mn-doping and the nature of the capping layer on the strain level. [ABSTRACT FROM AUTHOR]

A composite nanostructure comprising of Au and Ge gradually evolves on SiO 2 surface when a bilayer of Au and Ge is irradiated by medium keV Xe-ion beam. The morphology progresses through different stages from nucleating patches to extended islands and finally a Au-Ge composite nanodot array develops on the insulator surface. While ion energy and fluence are found to determine dimensions of the nanostructures, existence of a characteristic lateral length scale is also detected at every stage of evolution. Through morphological and compositional analysis, the observed evolution is understood as an effect of ion beam induced dewetting of Au top layer. Numerical estimation based on the unified thermal spike model using the present experimental condition demonstrates formation of molten zones around the ion track due to nuclear and electronic energy deposition in the target. Dewetting results from mass flow onto the surface driven by local melting along the ion track and combines with sputter erosion of the bilayer film to lead to composite nanodot evolution. The generality of the ion induced processes provides possible route towards metal-semiconductor hybrid nanostructure synthesis on insulator surface. [ABSTRACT FROM AUTHOR]

We experimentally show that, unlike the solid–solid frictional force, the solid–liquid retention force is determined by interactions at the triple line rather than over the solid–liquid contact area, as predicted by theory. We have prepared drops whose triple line enclosed a uniform surface, a hydrophobic island, and topographical inhomogeneities, and measured the same retention force for all three cases. We have also studied the retention force on drops whose initial triple line was non-circumferential and measured different retention forces for different shapes, also as predicted by theory. The experiments with non-circumferential drops provide (1) another way to show that the retention force is not proportional to the contact area, and (2) a manner to falsify a recent theory on drop depinning. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: This study was designed to develop a novel technique called non-invasive keratograph dry-up time (NIK-DUT), which used an adapted corneal topographer, to analyse in-vitro contact lens surface dewetting and the effects of combinations of lenses and lens care solutions on dewetting.Methods: Variables were assessed to optimise sensitivity and reproducibility. To validate the method, in-vitro dewetting of silicone hydrogel contact lenses (balafilcon A, comfilcon A, lotrafilcon A, lotrafilcon B and senofilcon A) was tested. All lens types were soaked in OPTI-FREE® PureMoist® Multipurpose Disinfecting Solution (OFPM) and Sensitive Eyes® Saline Solution. The mean NIK-DUT, defined as drying of 25% of the placido ring measurement segments (NIK-DUT_S25), was calculated for each lens/lens solution combination and a visual map constructed representing the time and location of the dry-up event.Results: Optimal conditions for NIK-DUT measurement included mounting onto a glass stage with a surface geometry of r=8.5mm, e=0, and measuring with high intensity red or white illumination. This method detected significant differences in contact lens dewetting with different lens soaking solutions. NIK-DUT_S25 for all lenses was longer when pre-soaked in OFPM versus saline. Visual analysis showed that dewetting of contact lenses was not uniform across surfaces and differed between test solutions.Conclusions: NIK-DUT is suitable for detecting differences in dewetting among various contact lenses and lens-care combinations. NIK-DUT can quantify the dewetting of large areas of lens surfaces with little subjective influence. Lens care solutions containing surface-active wetting agents were found to delay surface dewetting of silicone hydrogel lenses. [ABSTRACT FROM AUTHOR]

Solid state dewetting of Au/Ni bilayer films was investigated by in-situ cross-sectional TEM heating with energy-dispersive X-ray spectroscopy. The early stage of dewetting process revealed both grain boundary grooving at the surface of the Ni layer and void nucleation along the Au/Ni interface between Au grains. During annealing, inter-diffusion occurred and enhanced solubility was found between Au and Ni. Au diffused predominantly through Ni grain boundaries and decorated the Ni/substrate interface. The energetically preferred adsorption of Au at the Ni/SiO 2 interface and at Ni grain boundaries, coupled with some alloying in the volume of the metal films delays the break-up of the bilayer film compared to pure Au or Ni films. The experimental observations confirm that dewetting kinetics of metal bilayer films are strongly affected by both partial alloying of the metals as well as the metal/metal interface. [ABSTRACT FROM AUTHOR]

In this work the results on thermal nanostructuring of the Au films on Ti templates as well as morphology and optical properties of the obtained structures are reported. The bimetal nanostructures are fabricated in a multi-step process. First, the titania nanotubes are produced on the surface of Ti foil by anodization in an ethylene glycol-water solution containing fluoride ions. This is followed by chemical etching in oxalic acid and results in a highly ordered dimpled surface. Subsequently, thin gold films (5–20 nm) are deposited onto prepared Ti substrates by magnetron sputtering. The as-prepared layers are then dewetted by the UV nanosecond laser pulses or alternatively in the furnace (temperature < 500 °C). The SEM inspection reveals formation of honeycomb nanostructures (cavity diameter: ∼100 nm) covered with Au nanoparticles (NPs). It is observed that both the laser annealing and continuous thermal treatment in furnace can lead to the creation of NPs inside every Ti dimple and result in uniform coating of the whole area of structured templates. The size and localization of NPs obtained via both dewetting processes as well as their shape can be tuned by the annealing time and the laser processing parameters and also by initial thickness of Au layer and presence of the dimples themselves in the substrate. Results confirm that the prepared material can be used as substrate for SERS (Surface Enhanced Raman Spectroscopy). [ABSTRACT FROM AUTHOR]

Wetting of partially wettable porous solids is encountered in many and diverse applications such as imbibition of liquid reactants into pores of porous catalysts and adsorbents in reactor beds, water vapor condensation on porous substrates like leaves, and spreading of liquid condensate on fuel cell membranes. This wetting is a combination of liquid spreading/retraction on the external surface and imbibition into the pores. In this paper, we establish the basic “building block” of this problem, i.e. , the dynamics of wetting and retraction of a thin film in the vicinity of a single infinite pore of a porous solid and show the way forward by discussing the case of two such adjacent pores. The coupled process described by a unified and simple model derived from equations of motion under the lubrication approximation for thin film flow on the external surface and Hagen-Poiseulle flow inside the pores. A single final evolution equation tracks the externally wetted region in time by solving for the height of the liquid surface starting from an initial liquid droplet. The wetted area initially expands as the droplet spreads and then contracts as droplet retracts due to imbibition in the pore. The liquid surface becomes increasingly liable to rupture under the influence of intermolecular forces as it thins because of imbibition. The governing equation can track the rupture and subsequent dewetting of the surface also. The liquid morphology and kinetics of wetting show good agreement with the reported experiments implying that the description of a spreading liquid as a thin film indeed manages to incorporate the most important physics governing the internal wetting of liquids on porous substrates at the micro scale. The model shows a possible way to develop wetting correlations for larger scales of flow in industrial trickle bed reactors in a bottom-up manner. [ABSTRACT FROM AUTHOR]

The solid state dewetting of Au/Ni bilayer films was investigated by cross-sectional transmission electron microscopy techniques, including energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy and precession electron diffraction. After annealing under high vacuum conditions the early stage of film agglomeration revealed significant changes in film morphology and chemical distribution. Both Au and Ni showed texturing. Despite the initial deposition sequence of the as-deposited Au/Ni/SiO 2 /Si interface structure, the majority of the metal/SiO 2 interface was Au/SiO 2 after annealing at 675 ° C for 1 h. Void nucleation was predominantly observed at Au/Ni/SiO 2 triple junctions, rather than grain boundary grooving at free surface of the metal film. Detailed cross-sectional characterization reveals that the Au/Ni interface in addition to small amounts of metal alloying strongly affects film break-up and agglomeration kinetics. The formation of Au/SiO 2 interface sections is found to be energetically preferred over Ni/SiO 2 due to compressive stress in the as-deposited Ni layer. Void nucleation is observed at the film/substrate interface, while the formation of voids at Ni/Au phase boundaries inside the metal film is caused by the Kirkendall effect. [ABSTRACT FROM AUTHOR]

We probe the effects of grain boundaries on thin film dewetting numerically for initially circular and elongated holes in single and bi-crystalline systems. We find that grain boundaries play a critical role in determining hole morphologies, in particular in the formation of highly branched hole morphologies, since while elongated holes in single crystals tend to become rounder over time, circular holes in bi-crystals destabilize, leading to accelerated dewetting along the grain boundaries. [ABSTRACT FROM AUTHOR]

We have monitored the evolution of the optical properties of ultrathin N,N′-dipentylperylene-3,4,9,10-tetracarboxylic diimide (PTCDI-C 5 ) molecular thin films during their growth on muscovite mica surfaces using differential reflectance spectroscopy (DRS) and fluorescence spectroscopy (FL). In the monolayer regime, the DRS shows a monomer-like absorption, whereas the FL reveals a transition from monomeric to excimer-like emission accompanied by a quenching of the intensity with the increase of coverage. The observed evolution of the FL signals can be explained by a two dimensional (2D) gas to condensed phase transition. The characteristic fluorescence of the condensed phase implies an enhancement of the intermolecular coupling and the opening of new channels for the relaxation of the excited state. The π – π stacking, which is manifested by both DR and FL spectroscopies, emergences only after the completion of the first monolayer. Finally, by analyzing the variation of the fluorescence spectrum, we have revealed the dewetting of the uncompleted PTCDI-C 5 monolayer upon air exposure. This observation has been verified by atomic force microscopy (AFM). [ABSTRACT FROM AUTHOR]

Sequential Cu(In,Ga)Se 2 fabrication with a thermally activated reaction of Cu-In-Ga metal precursor layers in chalcogen atmosphere is an industrially attractive route for preparation of Cu(In,Ga)Se 2 absorber based thin film solar cells. Recent results show that controlling the selenium supply during rapid thermal processing has a huge impact on absorber growth. Especially a two stage process applying a first annealing step with or without Se at temperatures up to 400 °C was shown to have a positive effect on the elemental in-depth distribution. However, during this annealing, lateral phase separation, dewetting and coarsening may occur in the metal phase, leading to lateral non-uniformity of the absorber. In this study we show how the dewetting can be strongly decreased by adjusting the precursor architecture, applying faster heating rates and NaF addition on top of a precursor. In contrast, NaF deposited underneath the precursor increases the dewetting effect. Further we show that lateral phase separation during annealing increases with temperature and leads to phase domain sizes of several micrometers at 580 °C. [ABSTRACT FROM AUTHOR]

Thin metallic films are unstable under thermal treatment and disintegrate into particles in a process known as solid state dewetting. This process was studied by annealing 30 nm thin gold films, deposited on flat and structured silicon substrates, by means of electron scanning microscopy and electron backscattered diffraction. Two different modes of decomposition were observed; formation of doughnut-shaped islands which coalesced into dendritic particles of gold with a network of gold particles in between, and patterns which start as circular holes with pronounced rims and subsequently develop in a typical pattern. In the case of structured substrates confinement of particles within ridges was observed for deep scratches, while shallower scratches allowed some spill over of the material. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate an original elaboration route for producing a Mn-doped Ge self-assembled quantum dots on SiO 2 thin layer for MOS structure. These magnetic quantum dots are elaborated using dewetting phenomenon at solid state by Ultra-High Vacuum (UHV) annealing at high temperature of an amorphous Ge:Mn (Mn: 40%) nanolayer deposed at very low temperature by high-precision Solid Source Molecular Beam Epitaxy on SiO 2 thin film. The size of quantum dots is controlled with nanometer scale precision by varying the nominal thickness of amorphous film initially deposed. The magnetic properties of the quantum-dots layer have been investigated by superconducting quantum interference device (SQUID) magnetometry. Atomic force microscopy (AFM), x-ray energy dispersive spectroscopy (XEDS) and transmission electron microscopy (TEM) were used to examine the nanostructure of these materials. Obtained results indicate that GeMn QDs are crystalline, monodisperse and exhibit a ferromagnetic behavior with a Curie temperature (TC) above room temperature. They could be integrated into spintronic technology. [ABSTRACT FROM AUTHOR]

Thin solid films have ubiquitous presence in many existing and emerging technologies. Solution-processed thin solid films may be fabricated by casting a thin liquid film followed by a drying step. It has been shown that by imposing a low-amplitude ultrasonic vibration on the substrate, the physical and structural characteristics of the resulting thin solid films is improved, significantly. Therefore, in this study, to investigate and rationalize the aforementioned findings, the evolution and stability of thin and ultrathin films of Newtonian liquid solutions, subjected to vertical and horizontal ultrasonic vibration is studied, using the long-wave approximation and negligible inertia forces. An explicit criterion is obtained for the film instability. Consistent with established theories, it is found that the vertical vibration tends to destabilize the thin liquid film, although for ultrasonic vibrations with low-amplitude, the term contributing to the perturbation growth rate decays rapidly with time and the film may remain stable. However, the vertical ultrasonic vibration is found as a significant destabilizing force, if the film thickness is near a critical value in which case the destabilizing van der Waals and stabilizing gravity and surface tension forces balance one another. To validate the model, experiments on thin liquid films of dilute polymeric solutions are performed. It is found that while imposing ultrasonic vibration may potentially destabilize and breakup the thin film, imposing a low-power vibration can significantly improve the homogeneity, electrical properties, and uniformity of the film, whereas a large-amplitude vibration may have a detrimental effect, because of excessive mixing and agitation of the liquid film or cracking of the resulting thin solid film. [ABSTRACT FROM AUTHOR]

We consider the discrete atomistic setting introduced in Piovano and Velčić (2022) to microscopically justify the continuum model related to the Winterbottom problem , i.e., the problem of determining the equilibrium shape of crystalline film drops resting on a substrate, and relax the rigidity assumption considered in Piovano and Velčić (2022) to characterize the wetting and dewetting regimes and to perform the discrete to continuum passage. In particular, all results of Piovano and Velčić (2022) are extended to the setting where the distance between the reference lattices for the film and the substrate is not smaller than the optimal bond length between a film and a substrate atom. Such optimal film–substrate bonding distance is prescribed together with the optimal film–film distance by means of two-body atomistic interaction potentials of Heitmann–Radin type, which are both taken into account in the discrete energy, and in terms of which the wetting-regime threshold and the effective expression for the wetting parameter in the continuum energy are determined. [ABSTRACT FROM AUTHOR]

Dewetting experiments on molten spherulites, previously grown at T c = 120 °C in thin films of isotactic polypropylene (iPP), revealed two kinds of instabilities of the dewetting rims, namely a fingering instability and a fracture instability for dewetting temperatures T s above and below ca. 165 °C, respectively. For T s ≥ 165 °C, the dynamics of growing dewetting holes on slippery substrates was governed by viscous dissipation, causing undulations leading to a fingering instability of the rims. However, for 160 °C < T s < 165 °C, the dewetting rims exhibited a fracture instability, which was related to the release of elastic energy stored in the rim. From the dewetting dynamics of the molten polymers, we derived the non-equilibrium viscosity η non-equ (T s) and equilibrated viscosity η equ (T s) as a function of T s. The values of η non-equ (T s) were significantly larger than η equ (T s), with differences decreasing for increasing T s. Interestingly, extrapolation of η non-equ (T s) to the cross-over point η non-equ = η equ yielded T s,cross ≈ 166 °C. We relate T s,cross with the maximum melting temperature of crystalline domains which existed within iPP spherulites. Below T s,cross , not all crystallites were molten and the melt contained crystalline seeds. Above T s,cross , the melt was homogeneous and free of any seeds. Our approach opens up a new possibility for determining the maximum melting temperature of polymer crystals. [Display omitted] • The fingering instability and fracture instability were respectively observed in homogeneous melt and heterogeneous melt. • The rim instability changed from fingering to fracture at 165 °C was revealed by dewetting of iPP films. • The non-equilibrium viscosity extrapolated to the equilibrium viscosity at a cross-over temperature T s,cross ≈ 166 °C. • The T s,cross was considered as the maximum melting temperature of crystalline domains within iPP spherulites. [ABSTRACT FROM AUTHOR]

• Substrate vibration promotes the dewetting of Ag film on SiO 2. • The characteristic dewetting time is dramatically decreased by vibration. • The inertance effect increases the film instability. Thermally-induced metallic film dewetting on a substrate has huge advantages in paralleled nanofabrication. Although various regulation method of the dewetting process have been investigated, a mobile supporting substrate has been rarely considered. This work investigates how the vertical vibration of a SiO 2 substrate affects the thermally-induced silver (Ag) film dewetting by molecular dynamics (MD) simulation. It is revealed that the substrate vibration can significantly promote the dewetting, which dramatically decreases the characteristic dewetting time. This principle of dewetting promotion remains for a tested range of film thickness from 0.2 nm to 0.6 nm. During the substrate vibration, the inertance of Ag film amplifies the film instability and thus promote the dewetting. For a 0.4 nm thick Ag film, the MD simulation shows that appropriate vibration period (T) and vibration amplitude (A) to achieve the promoted dewetting are approximately 2 ∼ 100 ps and 0.1 ∼ 0.4 Å, respectively. [ABSTRACT FROM AUTHOR]

• AgCuAl medium entropy alloy films were deposited on glass substrates. • Nanoparticles were induced by continuous wave laser dewetting process. • At lower unit volume energies (0.1 ∼ 1.3 J/cm3), the particles had a size of around 120 ∼ 130 nm. • A strong Raman scattering effect at 680 cm−1 in the presence of melamine in aqueous solution. AgCuAl films were deposited on glass substrates using a sputtering system. The films were dewetted using a continuous wave (CW) laser with a wavelength of 1070 nm and various settings of the laser power, duty cycle, and speed, respectively. The results showed that nanoparticles were produced for accumulated energies in the range of 0.1 ∼ 2.2 kJ/mm3. At lower unit volume energies (0.1 ∼ 1.3 kJ/mm3), the particles had a size of around 120 ∼ 130 nm. However, as the accumulated energy increased to 1.7 kJ/mm3, the particle size reduced to 95 nm. The AgCuAl films produced using a duty cycle of 30 % showed an optical absorption peak wavelength in the range of 600 ∼ 620 nm. Moreover, a blue shift was observed as the laser power increased as a result of the smaller particle size. AgCuAl nanoparticles (NPs) show a strong Raman scattering effect at 680 cm−1 in the presence of melamine solution. Hence, the feasibility of detecting melamine via surface-enhanced Raman spectroscopy was confirmed. [ABSTRACT FROM AUTHOR]