REVIEW | doi:10.20944/preprints202202.0258.v1
Subject: Materials Science, Nanotechnology Keywords: plasmonics; nanoscale; ablation; direct laser write; die-met
Online: 21 February 2022 (14:54:57 CET)
Nanoscale structuring/printing is of interest for range of applications in 3D subtractive and additive manufacturing (3D+/-). Basic principles of light field enhancement and control at the nanoscale are overviewed in this section/chapter for bulk, surface, and localised plasmons (1D, 2D, and 3D localisation, respectively). All these plasmons are resonant phenomena which have common Lorentzian spectral lineshape which relates refractive and absorption properties as well as defining the phase of transmitted and scattered light. Localisation of light at the nanoscale creates the possibility of modification with matching resolution. Harnessing this light enhancement can be demonstrated as a "nano-pen" for direct write nanolithography.
REVIEW | doi:10.20944/preprints202003.0082.v1
Subject: Materials Science, Polymers & Plastics Keywords: ARM-IR; polymers; polymer blends; polymer aging; nanoscale characterization
Online: 5 March 2020 (04:03:23 CET)
Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. In this perspective paper, we review recent progress in the use of AFM-IR in polymer science. We describe first the principle of AFM-IR and the recent improvements to enhance its resolution. We discuss then the last progress in the use of AFM-IR as a super-resolution correlated scanned-probe IR spectroscopy for chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers and biopolymers. To highlight the advantages of AFM-IR, we report here several results in studying crystallization of both miscible and immiscible blends as well as polymer aging. Then, we demonstrate how this novel technique can be used to determine phase separation, spherulitic structure and crystallization mechanisms at the nanoscale, which have never been achieved before. The review also discusses future trends in the use of AFM-IR in polymer materials, especially in polymer thin film investigation.
ARTICLE | doi:10.20944/preprints202104.0609.v1
Subject: Physical Sciences, Acoustics Keywords: nanoscale system; quantum transport; Coulomb blockade; entropy measurement; thermodynamic relations
Online: 22 April 2021 (13:29:10 CEST)
The entropy of a system gives a powerful insight into its microscopic degrees of freedom, however standard experimental ways of measuring entropy through heat capacity are hard to apply to nanoscale systems, as they require the measurement of increasingly small amounts of heat. Two alternative entropy measurement methods have been recently proposed for nanodevices: through charge balance measurements and transport properties. We describe a self-consistent thermodynamic framework for treating few-electron nanodevices which incorporates both existing entropy measurement methods, whilst highlighting several ongoing misconceptions. We show that both methods can be described as special cases of a more general relation and prove its applicability in systems with complex microscopic dynamics – those with many excited states of various degeneracies.
ARTICLE | doi:10.20944/preprints201806.0167.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: surface removal; nanoscale process; copper thin film; ultrathin water film
Online: 12 June 2018 (06:11:36 CEST)
The surface planarity and asperity removal behaviors of atomic scale under the ultrathin water environment was studied for the nanoscale process by molecular dynamics simulation. The monolayer atomic removal was achieved under the noncontact and monoatomic layer contact conditions with different water film thickness, and the newly formed surface is relatively smooth and no deformed layer and plastic defects exist. The nanoscale processing is governed by the interatomic adhering action during which the water film transmits the loading forces to Cu surface and thereby result in the migration and removal of surface atoms. With scratching depth ≥ 0.5 nm, the abrasive particle squeezed out the water film from scratching region and scratched Cu surface directly, leading to the surface quality deterioration mainly governed by the plowing action. This study brings the goals of “0 nm planarity, 0 residual defects and 0 polishing pressure” closer to us in the nanoscale process for the development of ultra-precision manufacture technology.
ARTICLE | doi:10.20944/preprints202212.0514.v1
Subject: Materials Science, Nanotechnology Keywords: nano-alloy; Si-Cr; Si nano-needles; sub-100 nm; nanoscale
Online: 27 December 2022 (08:41:50 CET)
Ultra-short 230 fs laser pulses of 515 nm wavelength were tightly focused into 700 nm focal spots and utilised in opening ~ 400 nm nano-holes in a Cr etch mask that was tens-of-nm thick. Nano-holes ablated at slightly above the threshold of ablation irradiance became nano-disks and nano-rings at slightly lower pulse energies. Subtle sub-1 nJ pulse energy control was harnessed to pattern large surface areas with controlled nano-alloying of Si and Cr. This technique is extendable to vacuum-free large area patterning of nanolayers by alloying them at distinct locations with sub-diffraction resolution. Such metal masks with nano-hole opening can be used for formation of random patterns of nano-needles with sub-100 nm separation when applied to dry etching of Si.
ARTICLE | doi:10.20944/preprints202210.0288.v1
Subject: Materials Science, Nanotechnology Keywords: Proteomics; 2D SDS-PAGE; Nanoscale and ionic metals; Quantum dots; Hyperaccumulator
Online: 19 October 2022 (13:14:25 CEST)
Hyperaccumulator plant species growing on metal-rich soils can accumulate high quantity of metals and metalloids in aerial tissues and several proteomic studies on the molecular mechanisms at the basis of metals resistance and hyperaccumulation have been published. Hyperaccumulator are also at the basis of phytoremediation strategy to remove more efficiently metals from polluted soils or water. Arabidopsis halleri and Noccea caerulescens are both hyperaccumulators of metals and nano-metals. In this study it was assessed the change in some proteins in A. halleri and N. caer-ulescens after the growth in soil with cadmium and zinc, provided as sulphate salts (CdSO4 and ZnSO4) or sulfide quantum dots (CdS QDs and ZnS QDs). The protein extracts obtained from plants after 30 days of growth were analyzed by 2D-gel electrophoresis (2D SDS-PAGE) and identified by MALDI-TOF/TOF mass spectrometry. A bioinformatics analysis was carried out on quantitative protein differences between control and treated plants. In total, 43 proteins resulted significatively modulated in A. halleri, while 61 resulted modulated in N. caerulescens. Though these two plants are hyperaccumulator of both metals and nano-metals, at protein levels the mechanisms involved do not proceed in the same way but at the end bring to a similar physiological result.
ARTICLE | doi:10.20944/preprints202007.0126.v1
Subject: Engineering, Mechanical Engineering Keywords: Coarse Grain Models; Water Models; Nanoscale Evaporation; Nano Channels; Molecular Dynamics
Online: 7 July 2020 (11:03:25 CEST)
Evaporation studies of water using classical molecular dynamics simulations are largely limited due to its high computational expense. We aim at addressing the computational issues by developing a coarse grain model for evaporation of water on solid surfaces by combining four water molecules into a single bead. Most commonly used mono atomic pair potentials like Lennard Jones, Morse, Mie and three body potential like Stillinger-Weber are optimized using a combination of Genetic algorithm and Nelder-Mead algorithm. Among them, Stillinger-Weber based model shows excellent agreement of density and Enthalpy of vaporization with experimental results for a wide range of temperatures. Further, the new water model is used to simulate contact angle of water and thin film evaporation from surfaces with different wettabilities.
ARTICLE | doi:10.20944/preprints201701.0028.v9
Subject: Materials Science, General Materials Science Keywords: heat energy; photon energy; fundamental forces; nanoscale phenomenon; atomic scale phenomenon; electron scale phenomenon
Online: 8 December 2017 (03:46:45 CET)
Technology is in the way to reach in its climax but the basic understanding of science in many phenomena is still awaited even though the nature witnesses it. Scientific research reveals strong analogy between photon and electron. When an atom deals neutral state, it levitates electron of outer ring from the back surface while placing the bit-energy at front surface. Gravitation behavior of that electron starts at the centre of relaxation point by including the force of side pole where the pulling force of nearby unfilled state of that atom from the front surface results into depict forcing energy shape like Gaussian distribution symbol with both ends turned called unit photon. The inertia is being involved at each stage of changing direction of that electron by introducing the disappearances of forces of two poles against the appearances of forces of two opposite poles during rest to motion and motion to rest in the first half-cycle. The same is the case in the second half-cycle of that electron during rest to motion and motion to rest but it is under different introduction of the disappearances of forces against appearances of forces. However, at stage of levitating or gravitating period of electron, only one force is being involved at one time where the opposite force is disappeared. The uninterrupted confined inter-state electron-dynamics of atom under the availability of several bits of bit-energy results into generate forcing energy shape like a wave. Two bits of bit-energy where shape of bit for first half-cycle is like integral symbol and second half-cycle is like opposite integral symbol which are being placed along the configuring trajectory of inter-state electron-dynamics during forward-direction cycle and two bits of bit-energy shape in opposite order are being placed along the trajectory of inter-state electron-dynamics during back-direction cycle. Generating forcing energy of unit photon in each cycle is pushing to the rear side by remaining connected till the electron is not restoring the state of rest. Silicon atom is considered as a model system under neutral state. Uninterrupted confined inter-state electron-dynamics result into generate forcing energy that can travel immeasurable length and unavailability of necessitating bit-energy at any interrupted stage result into generate an overt photon. Inter-state electron-dynamics for at least two cycles generate an overt photon –a photon length twice to unit photon. Under certain interaction of unit photon, it divides equally into two bits of bit-energy instead of dividing into tits and bits of heat. The mechanism of generating photon characteristic current by the electron of neutral state atom validates that atoms are four-dimensional discs at centre of dealing no force. An isolated electron is being grounded under directed forcing energy to impinge a neutral state atom where the gained instantaneous velocity under merged energy resulting into distort atom at that point. Matter changes the role of energy and force under various sorts of interactions. Here, heat energy and photon energy explore matter at atomic and electron levels, thus, devise basis of science to describe.
ARTICLE | doi:10.20944/preprints202008.0200.v1
Subject: Materials Science, Metallurgy Keywords: oxide glasses; strength; ductility; work hardening ability; nanoscale heterogeneities; molecular dynamics simulations
Online: 8 August 2020 (03:15:33 CEST)
We prepared heterogeneous alumina-silicate glasses by consolidating nanoparticles using molecular dynamics simulations. Consolidated glasses from either low alumina content alumina-silicate glasses or high alumina content alumina-silicate glasses show significantly improved ductility around consolidation pressure of ~3 GPa. The introduced structural heterogeneities, namely over-coordinated network formers and their neighboring oxygen atoms, are identified as plasticity carriers due to their high rearrangement propensity. In addition, consolidated oxide glass from both 23.4Al2O376.6SiO2 and 73.1Al2O326.9SiO2 nanoparticles show improved flow strength (up to 1 GPa) due to the introduction of chemical heterogeneities. Last but not least, apparent hardening behavior appears upon cold work in consolidated glasses, with an increase of yield strength from ~3.3 GPa to ~6.4 GPa. This method is a big advancement toward ultra-strong and ultra-tough glasses by breaking the structure, composition and size limitations in traditional melt-quench process.
ARTICLE | doi:10.20944/preprints201608.0151.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Nanoscale silicon, optical waveguides, Mach-zehnder interferometer, directional coupler, thermal sensor, optical switches
Online: 15 August 2016 (11:26:43 CEST)
A compact Mach-zehnder interferometer with a novel design of directional couplers and a phase shifter has been presented as a thermo-optical sensor. With the aim of reducing device size to micro and nano dimension silicon-on-insulator technology was employed. That allowed miniaturization of device size through the reduction of its cross sectional area to 0.066 µm2 and the radius of curvature of both the arms of the directional coupler and S-bends of the phase shifter to 5 µm and C-bends to 3 µm. These nano size device dimensions made it possible to reduce the coupling gap to 0.2 µm, which resulted in a significant reduction in the coupling length. The device geometry and its performance characteristics were analyzed and optimized using coupled mode analysis and finite difference time domain simulation tools, respectively. The wavelength dependent transmission loss of the device was measured at different temperature to verify and validate its performance characteristics. Tested devices showed a remarkable temperature dependent transmission characteristic offering significant changes in transmission loss band – with as low as 0.45 0C change in substrate temperature. The extinction ratio and the free spectral range of the device were 26 dB and 0.26 nm respectively in the wavelength range of 1549.5 nm – 1550.5 nm. These results imply that the devices presented here can be used as compact and highly sensitive thermal sensors and optical switches.
ARTICLE | doi:10.20944/preprints201809.0412.v1
Subject: Physical Sciences, Applied Physics Keywords: Additive-Manufacturing, 3D Printing, Glass-Ceramics, Nanoscale, Laser 3D lithography, SZ2080, Cristobalite, Zirconia, Nanocomposites, Calcination
Online: 20 September 2018 (13:52:10 CEST)
Fabrication of a true-3D inorganic ceramic with resolution down to nanoscale using sol-gel resist precursor is demonstrated. The method has an unrestricted free-form capability, control of the fill-factor, and high fabrication throughput. A systematic study of the proposed approach based on ultrafast laser 3D lithography of organic-inorganic hybrid sol-gel resin followed by a heat treatment enabled formation of inorganic amorphous and crystalline composites guided by the composition of the initial resin. The achieved resolution of 100 nm was obtained for 3D patterns of complex free-form architectures. Fabrication throughput of 50×103 voxels/s is achieved; voxel - a single volume element was recorded by a single pulse exposure. After a subsequent thermal treatment, ceramic phase was formed depending on the temperature and duration of the heat treatment as validated by Raman micro-spectroscopy. The X-ray diffraction (XRD) revealed a gradual emergence of the crystalline phases at higher temperatures with a signature of cristobalite SiO2, a high-temperature polymorph. Also, the tetragonal ZrO2 phase known for its high fracture strength was observed. This 3D nano-sintering technique is scalable from nano- to millimeter dimensions and opens a conceptually novel route for optical 3D nano-printing of various crystalline inorganic materials defined by an initial composition for diverse applications for microdevices in harsh physical and chemical environments and high temperatures.
REVIEW | doi:10.20944/preprints202010.0035.v1
Subject: Physical Sciences, Acoustics Keywords: Photopolymerization; Additive manufacturing; Ultrafast laser; Multiphoton lithography; Laser 3D nanolithography; Nanoscale; Organic and hybrid materials; Bio-derived materials; Functional 3D structures; Advanced material engineering
Online: 2 October 2020 (09:30:53 CEST)
Ultrafast laser 3D lithography based on non-linear light-matter interactions, widely known as multi-photon lithography (MPL), offers unrivaled precision rapid prototyping and flexible additive manufacturing options. 3D printing equipment based on MPL are already commercially available, yet there is still no comprehensive understanding of factors determining spatial resolution, accuracy, fabrication throughput, repeatability, and standardized metrology methods for the accurate characterization of the produced 3D objects and their functionalities. The photoexcitation mechanisms, spatial-control or photo-modified volumes, and the variety of processable materials are topics actively investigated. The complexity of the research field is underlined by limited understanding and fragmented knowledge of light-excitation and material response. Research to date has only provided case-specific findings on photoexcitation, chemical modification, and material characterization of the experimental data. In this review, we aim to provide a consistent and comprehensive summary of the existing literature on photopolymerization mechanisms under highly confined spatial and temporal conditions, where, besides the excitation and cross-linking, parameters such as diffusion, temperature accumulation, and the finite amount of monomer molecules start to become of critical importance. Key parameters such as, photoexcitation, polymerization kinetics, and the properties of the additively manufactured materials at the nanoscale in 3D are examined, whereas, the perspectives for future research and as well as emerging applications are outlined.
ARTICLE | doi:10.20944/preprints201802.0163.v1
Subject: Physical Sciences, Optics Keywords: optical metamaterials; fundamental concepts in photonics; light-matter interactions at the subwavelength and nanoscale; fundamental understanding of linear and nonlinear optical processes in novel metamaterials underpinning photonic devices and components; advancing the frontier of nanophotonics with the associated nanoscience and nanotechnology; nanostructures that can serve as building blocks for nano-optical systems; use of nanotechnology in photonics; nonlinear nanophotonics, plasmonics and excitonics; subwavelength components and negative index materials; slowing, store, and processing light pulses; materials with such capabilities that could be used for optical sensing, tunable optical delay lines, optical buffers, high extinction optical switches, novel image processing hardware, and highly-efficient wavelength converters
Online: 26 February 2018 (11:24:39 CET)
Backward electromagnetic waves are extraordinary waves with contra-directed phase velocity and energy flux. Unusual properties of the coherent nonlinear optical coupling of the phase-matched ordinary and backward electromagnetic waves with contra-directed energy fluxes are described which enable greatly-enhanced frequency and propagation direction conversion, parametrical amplification, as well as control of shape of the light pulses. Extraordinary transient processes that emerge in such metamaterials in pulsed regimes are described. The results of the numerical simulation of particular plasmonic metamaterials with hyperbolic dispersion are presented, which prove the possibility to match phases of such coupled guided ordinary and backward electromagnetic waves. Particular properties of the outlined processes in the proposed metamaterial are demonstrated through numerical simulations. Potential applications include ultra-miniature amplifiers, frequency changing reflectors, modulators, pulse shapers, and remotely actuated sensors.