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Defects are inherent in transition metal dichalcogenides and significantly affect their chemical and physical properties. In this study, surface defect electrochemical nanopatterning is proposed as a promising method to tune in a controlled manner the electronic and functional properties of defective MoS₂ thin films. Using parallel electrochemical nanolithography, MoS₂ thin films are patterned, creating sulphur vacancy‐rich active zones alternated with defect‐free regions over a centimetre scale area, with sub‐micrometre spatial resolution. The patterned films display tailored optical and electronic properties due to the formation of sulphur vacancy‐rich areas. Moreover, the effectiveness of defect nanopatterning in tuning functional properties is demonstrated by studying the electrocatalytic activity for the hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

3D nanolithography based on two‐photon polymerization (TPP) allows for the high‐precision fabrication of nearly arbitrary 3D micro/nanostructures, finding extensive applications in areas such as micro‐optics, micro‐mechanics, and biomedicine. However, the large size, complexity of optical systems, and high costs have significantly constrained the widespread adoption of 3D nanolithography technology in both scientific research and industry. In this study, a metasurface is introduced, for the first time, into 3D nanolithography resulting in the construction of a miniaturized and simplified TPP system that achieved efficient multi‐focus parallel processing with high uniformity. A microlens array is fabricated, showcasing the system's application capacity to generate an array of devices with high consistency and quality. It is believed that the utilization of metasurface devices will provide a novel TPP operating platform, enabling richer and more flexible printing functionalities while maintaining system miniaturization and low cost. [ABSTRACT FROM AUTHOR]

Plasmonic nanostructures are frequently utilized to create metasurfaces with a large variety of optical effects. Control over shape and positioning of the nanostructures is key to the function of such plasmonic metasurfaces. Next to lithographic means, directed self‐assembly is a viable route to create plasmonic structures on surfaces with the necessary precision. Here, a combined approach of DNA origami self‐assembly and electron beam lithography is presented for determinate positioning of gold nanospheres on a SiO2 surface. First, DNA origami structures bind to the electron beam‐patterned substrate and subsequently, gold nanoparticles attach to a defined binding site on the DNA origami structure via DNA hybridization. A sol‐gel reaction is then used to grow a silica layer around the DNA, thereby increasing the stability of the self‐assembled metasurface. A mean yield of 74% of single gold nanospheres is achieved located at the determinate positions with a spatial position accuracy of 9 nm. Gold nanosphere dimers and trimers are achieved with a rate of 65% and 60%, respectively. The applicability of this structuring method is demonstrated by the fabrication of metasurfaces whose optical response can be tuned by the polarization of the incoming and the scattered light. [ABSTRACT FROM AUTHOR]

Tin‐oxo clusters are increasingly recognized as promising materials for nanolithography technology due to their unique properties, yet their structural impacts on lithography performance remain underexplored. This work explores the structural impacts of heterometal strategies on the performance of tin‐oxo clusters in nanolithography, focusing on various metal dopants and their coordination geometries. Specifically, SnOC‐1(In), SnOC‐1(Al), SnOC‐1(Fe), and SnOC‐2 were synthesized and characterized. These clusters demonstrate excellent solubility, dispersibility, and stability, facilitating the preparation of high‐quality films via spin‐coating for lithographic applications. Notably, this work innovatively employs Atomic Force Microscopy‐based Infrared Spectroscopy (AFM‐IR), neutron reflectivity (NR), and X‐ray reflectivity (XRR) measurements to confirm film homogeneity. Upon electron beam lithography (EBL), all four materials achieve 50 nm line patterns, with SnOC‐1(In) demonstrating the highest lithography sensitivity. This enhanced sensitivity is attributed to indium dopants, which possess superior EUV absorption capabilities and unsaturated coordination environments. Further studies on exposure mechanisms indicated that Sn−C bond cleavage generates butyl free radicals, promoting network formations that induce solubility‐switching behaviors for lithography. These findings underscore the efficacy of tailored structural design and modulation of cluster materials through heterometal strategies in enhancing lithography performance, offering valuable insights for future material design and applications. [ABSTRACT FROM AUTHOR]

A dual fan-shaped structure covered with Ag films was investigated for generating twin photonic hooks (t-PHs). The t-PH characteristics of this structure are studied using the Finite-Difference Time-Domain (FDTD) method. The results show that by designing appropriate fan-shaped opening angles and angles of Ag films coverage, the switching between t-PHs, S-shaped t-PHs, and W-shaped t-PHs can be achieved, along with controlling over the bending angles. The maximum first, second, and third bending angles for the obtained W-shaped t-PHs are 51.3°, 36.4°, and 41.8°, respectively, while the Ag films angle is 5°. The investigated tunable morphology t-PHs provide innovative applications in the fields of nanolithography and integrated optics. [ABSTRACT FROM AUTHOR]

Exploring and taming the diffraction phenomena and divergence of light are foundational to enhancing comprehension of nature and developing photonic technologies. Despite the numerous types of nondiffraction beam generation technologies, the 3D deformation and intricate wavefront shaping of structures during propagation have yet to be studied through the lens of nanophotonic devices. Herein, the dynamic conversion of a circular Airy beam (CAB) to a Bessel beam with a single‐layer spin‐selective metasurface is demonstrated. This spatial transformation arises from the interplay of 1D local and 2D global phases, facilitating the 3D control of non‐diffractive light fields. An additional overall phase gradient and orbital angular momentum are introduced, which effectively altering the propagation direction and transverse fields of complex amplitude beams along the optical path. The manifested samples exhibit superior defect resistance, laying a crucial application in micro/nanolithography technologies. This approach expands the in‐plane spin‐selective mechanism and leverages the out‐of‐plane propagation dimension, allowing for integrated high‐resolution imaging, on‐chip optical micromanipulation, and micro/nanofabrication within a versatile nanophotonic platform. [ABSTRACT FROM AUTHOR]

To realize nanoscale manufacturing based on laser direct writing technology, objective lenses with high numerical apertures immersed in water or oil are necessary. The use of liquid medium restricts its application in semiconductors. Achieving nanoscale features on silicon by laser direct writing in a low refractive index medium has been a challenge. In this work, a microsphere assisted femtosecond laser far-field induced dewetting approach is proposed. A reduction in the full-width at half-maximum of the focused light spot is realized by modulating tightly focused light through microspheres and achieving a minimum feature size of 9 nm on silicon in ambient air with energy smaller than the ablation threshold. Theoretical analysis and numerical simulation of laser processing are performed based on a two-temperature model. Furthermore, we explored the potential of femtosecond laser-induced dewetting in nanolithography and demonstrated its ability to achieve an arbitrary structure on silicon. Our work enables laser-based far-field sub-10-nm feature etching on a large-scale, providing a novel avenue for nanoscale silicon manufacturing. [ABSTRACT FROM AUTHOR]

Hybrid strategies that combine conventional top-down lithography with bottom-up molecular assembly are of interest for a range of applications including nanolithography and sensors. Interest in these strategies stems from the ability to create complex architectures over large areas with molecular-scale control and precision. The molecular-ruler process typifies this approach where the sequential layer-by-layer assembly of mercaptoalkanoic acid molecules and metal ions are combined with conventional top-down lithography to create precise, registered nanogaps. However, the quality of the metal-ligated mercaptoalkanoic acid multilayer is a critical characteristic in generating reproducible and robust nanoscale structures via the molecular-ruler process. Therefore, we explore the assembly of alkanethiolate monolayers, mercaptohexadecanoic acid (MHDA) monolayers, and Cu-ligated MHDA multilayers on Au{111} substrates using atomic force microscopy and in situ dynamic spectroscopic ellipsometry. The chemical film thicknesses in situ dynamic spectroscopic ellipsometry agree with previous ex situ surface analytical methods. Moreover, in situ dynamic spectroscopic ellipsometry provides insight into the assembly process without interrupting the assembly process and potentially altering the characteristics of the resulting chemical film. By following the real-time dynamics of each deposition step, the assembly of the Cu-ligated MHDA multilayers can be optimized to minimize deposition time while having minimal impact to the quality of the chemical film. [ABSTRACT FROM AUTHOR]

Hollow beam is a peculiar structure beam, which has been widely used in various areas. Here, we propose a novel diffraction optical element to generate tunable hollow beams. This element is composed of periodic concentric rings. The phase of each ring is periodically distributed between -n and n and satisfies a complex variable function. By tuning the parameters of the structure, we can flexibly manipulate the size and length of the hollow beam. The length of the beam can be increased from 98 X to 248 X, and the full width at half maximum varies from 0.43 X to 0.61 X. Moreover, the light intensity and side lobe of the hollow beam can also be regulated using the designed diffraction optical element. The potential applications of this highly tunable hollow beam include optical nanomanipulation, microscopic imaging, and nanolithography. [ABSTRACT FROM AUTHOR]

The possibility of using a series of methacrylate-containing N,N-diethyl-4-(phenyldiazenyl)anilines with various para-substituents (–H, –Br, –NO2) relative to the azo group as photoinitiators of radical polymerization is considered. The electrochemical and photoluminescent properties of these compounds have been studied. In the presence of azo dyes, two-photon photopolymerization of pentaerythritol triacrylate was carried out using focused 780-nm radiation from a femtosecond laser. Structures with minimal dimensions of linear elements of 94 ± 5 nm were obtained by means of the DLW nanolithography technique, and 3D microstructures of complex architecture were fabricated. [ABSTRACT FROM AUTHOR]

Although this opinion paper tracks the career of Mike Hatzakis (as he liked to be called), and explains the impact he made on the IT industry, it is not intended to be comprehensive insofar as the work that was underway during his career is concerned. Thus, the intent is not to cite all relevant work in the field of Semiconductor lithography, where Mike made such an impact, but to provide a historic and human perspective of this remarkable man from the land of the Minotaur (Crete) and his career, the work he championed in his labs in the US and later Greece and his very human approach to science, technology, and to people.Unlabelled Image

Synchrotron light sources can provide the required spatial coherence, stability and control to support the development of advanced lithography at the extreme ultraviolet and soft X-ray wavelengths that are relevant to current and future fabricating technologies. Here an evaluation of the optical performance of the soft X-ray (SXR) beamline of the Australian Synchrotron (AS) and its suitability for developing interference lithography using radiation in the 91.8 eV (13.5 nm) to 300 eV (4.13 nm) range are presented. A comprehensive physical optics model of the APPLE-II undulator source and SXR beamline was constructed to simulate the properties of the illumination at the proposed location of a photomask, as a function of photon energy, collimation and monochromator parameters. The model is validated using a combination of experimental measurements of the photon intensity distribution of the undulator harmonics. It is shown that the undulator harmonics intensity ratio can be accurately measured using an imaging detector and controlled using beamline optics. Finally, the photomask geometric constraints and achievable performance for the limiting case of fully spatially coherent illumination are evaluated. [ABSTRACT FROM AUTHOR]

Target conditioning is a crucial ingredient of high-power extreme ultraviolet (EUV) source operation in state-of-the-art nanolithography. It involves deforming tin microdroplets into tens of nanometer-thin sheets, sheets which are subsequently irradiated by intense CO2 laser radiation to form a hot, EUV-emitting plasma. Recent experiments have found that a substantial fraction of the initial droplet mass is lost in the deformation phase through fragmentation. The goal of the present study is to investigate, using radiation-hydrodynamic modeling, how variations in the sheet mass affect EUV source power and the laser-to-in-band conversion efficiency (CE). It is found that high-mass sheets can "feed" the plasma with sufficient mass to sustain the production of in-band-emitting charge states over the course of laser irradiation. Low-mass sheets, on the contrary, cannot supply enough mass to sustain this production over the pulse, thus leading to a reduction in in-band power and CE. The dependence of CE on laser energy and target thickness is quantified, and a rather weak reduction of CE with increasing laser energy for high-mass sheets is identified. [ABSTRACT FROM AUTHOR]

Micromagnetic computations were performed to predict the magnetisation maps in thin elliptically shaped nanoparticles under a variable external magnetic field. Two materials were compared as the constituents of the nanoparticles: permalloy as an example of an isotropic magnet and cobalt, i.e., a hard magnetic material marked with a single easy axis. The interplay of the shape and magnetocrystalline anisotropy gives rise to a variety of switching scenarios, which may be of interest in designing memory storage devices. A fairly periodic shape-induced superlattice-like spin configuration occurs when the shape and magnetocrystalline easy axes are orthogonal. Possible applications as magnonic devices are discussed. [ABSTRACT FROM AUTHOR]

Vacuum ultraviolet (VUV) light plays a crucial role in various scientific and technological fields, such as nanolithography and biomedical treatments. However, the inherent nonlinear optical coefficient of nonlinear optical crystals is typically very low, and increasing the action length is often necessary to improve the nonlinear conversion efficiency. This makes it challenging for these materials to achieve high-density optoelectronic integration at the micro-/nano-scale. In this study, we propose a design for generating coherent VUV radiation close to 175 nm using second harmonic generation (SHG) with an absolute efficiency exceeding 1.2‰ mW−1. This is achieved by merging multiple bound state in the continuum modes in a free-standing photonic crystal slab. Even with fabrication imperfections at a level lower than 10% disorder, the SHG efficiency of the samples remains robust, maintaining an efficiency of at least 2‰. This research provides a beneficial platform for generating efficient VUV light in the nanoscale. [ABSTRACT FROM AUTHOR]

Metasurfaces enable precise control over the properties of light and hold promise for commercial applications. However, fabricating visible metasurfaces suitable for high‐volume production is challenging and requires scalable processes. Nanoimprint lithography is a cost‐effective and high‐throughput technique that can meet this scalability requirement. This work presents a mask‐templating nanoimprint lithography process for fabricating metasurfaces with varying fill factors and negligible wavefront aberrations using composite stamps. As a proof‐of‐concept, a 6 mm diameter metalens formed of silicon nitride nano‐posts with a numerical aperture of 0.2 that operates at 550 nm is demonstrated. The nanoimprinted metalens achieves a peak focusing efficiency of (81 ± 1)%, comparable to the control metalens made with electron beam lithography with a focusing efficiency of (89 ± 1)%. Spatially resolved deflection efficiency and wavefront data, which informs design and process optimization, is also presented. These results highlight nanoimprint lithography as a cost‐effective, scalable method for visible metasurface fabrication that has potential for widespread adoption in consumer electronics and imaging systems. [ABSTRACT FROM AUTHOR]

The damping spectrum of surface plasmon polaritons (SPPs) is significantly enhanced for atom localization in regions beneath λ / 20 × λ / 20. By changing the phases and directions of control fields, two and single localization peaks are observed in the SPP damping spectrum. Circular and elliptical localization peaks are predominantly controlled in the λ 2 areal region of − π ≤ k x ≤ π and − π ≤ k y ≤ π. Additionally, craters and sharp peaks resembling localization can be modified and controlled within the two-dimensional space of λ 2 with a resolution smaller than λ 2 / 400. These modifications may be advantageous to the trapping of neutral atoms, nanolithography, and plasmonics technology. [ABSTRACT FROM AUTHOR]

Improving the 3D resolution is a decisive step in the transition of direct laser writing from being limited to research use to being a powerful tool. Three‐color (3CL) lithography is expected to result in significantly higher resolution with two‐color lasers initiating polymerization in two steps and one‐color laser inhibiting polymerization. However, the 3CL process increases the complexity of the system and makes the influence of chromatic aberration worse which leads to non‐ideal writing results, which is ≈80 nm linewidth (≈λ/10) at present. In this study, the 3CL lithography is improved by introducing almost one color (1CL) instead of three colors to achieve subdiffraction 3D nanolithography based on two‐photon two‐step absorption and photoinhibition (T2A‐PI). Using benzil as a photoinitiator, a sub‐30 nm (<λ/17.5) lateral feature size, minimum 80 nm lateral, and 160 nm axial pitches are achieved, which, to our knowledge, is the best to be fabricated using the laser in the visible region. 3D woodpile photonic crystals and other high‐quality nanostructures are fabricated, demonstrating the unique advantages over existing direct laser writing technologies. [ABSTRACT FROM AUTHOR]

Magnonic crystals are metamaterials whose magnon behavior can be controlled for specific applications. To date, most magnonic crystals have relied on nanopatterning and magnetostatic waves. Here, we analytically and numerically investigate magnonic crystals defined by modulating magnetic parameters at the nanoscale, which predominantly act on exchange-dominated, sub-100 nm magnons. We focus on two cases: the variation in the exchange constant, and the DMI constant. We found that the exchange constant modulation gives rise to modest band gaps in the forward volume wave and surface wave configurations. The modulation of the DMI constant was found to have little effect on the magnonic band structure, leading instead to a behavior expected for unpatterned thin films. We believe that our results will be interesting for future experimental investigations of nano-designed magnonic crystals and magnonic devices, where material parameters can be locally controlled, e.g., by thermal nano-lithography. [ABSTRACT FROM AUTHOR]

Silicon nanowires (SiNWs) are emerging as versatile components in the fabrication of sensors for implantable medical devices because of their exceptional electrical, optical, and mechanical properties. This paper presents a novel top-down fabrication method for vertically stacked SiNWs, eliminating the need for wet oxidation, wet etching, and nanolithography. The integration of these SiNWs into body channel communication (BCC) circuits was also explored. The fabricated SiNWs were confirmed to be capable of forming arrays with multiple layers and rows. The SiNW-based pH sensors demonstrated a robust response to pH changes, and when tested with BCC circuits, they showed that it was possible to quantize based on pH when transmitting data through the human body. This study successfully developed a novel method for SiNW fabrication and integration into BCC circuits, which could lead to improvements in the reliability and efficiency of implantable medical sensors. The findings demonstrate significant potential for bioelectronic applications and real-time biochemical monitoring. [ABSTRACT FROM AUTHOR]

In this work, we present a binary assembly model that can predict the co-assembly structure and spatial frequency spectra of monodispersed nanoparticles with two different particle sizes. The approach relies on an iterative algorithm based on geometric constraints, which can simulate the assembly patterns of particles with two distinct diameters, size distributions, and at various mixture ratios on a planar surface. The two-dimensional spatial-frequency spectra of the modeled assembles can be analyzed using fast Fourier transform analysis to examine their frequency content. The simulated co-assembly structures and spectra are compared with assembled nanoparticles fabricated using transfer coating method are in qualitative agreement with the experimental results. The co-assembly model can also be used to predict the peak spatial frequency and the full-width at half-maximum bandwidth, which can lead to the design of the structure spectra by selection of different monodispersed particles. This work can find applications in fabrication of non-periodic nanostructures for functional surfaces, light extraction structures, and broadband nanophotonics. [ABSTRACT FROM AUTHOR]

Nanoglasses have attracted considerable interest among material scientists due to their novel and surprising properties. However, there is still a significant gap in understanding how nanoglasses interact with biomaterials and their effects on living cells. Previous cell studies have reported indications of possible proliferation effects, but a comprehensive understanding of differentiating nanoglass influences from distinct material or topography effects is yet to be established. In this study, the interaction between nanoglass surfaces and phospholipids, which are fundamental components of cell membranes, is investigated. The findings reveal a unique stabilizing effect exhibited by nanoglasses on structures created using lipid dip‐pen nanolithography, preventing their spreading over the surface ("confinement"). This discovery suggests that nanoglasses can potentially influence the structure of cell membranes, providing a conceivable mechanism for how nanoglasses may impact cell behavior. [ABSTRACT FROM AUTHOR]

As increasingly more demanding photonics applications are brought on‐chip, more complex design solutions are employed to deliver enhanced performance: e.g., meta‐molecules, inverse‐designed freeform structures, and multilayer metasurfaces. Instead, this study introduces anti‐reflective metasurfaces fabricated in a single nanolithography step that follows deposition of multiple dielectrics onto a substrate. Anti‐reflective metasurfaces offer fundamentally better transmission efficiencies compared to conventional equivalents. Conventional and anti‐reflective metalenses, both fabricated in the Ta2O5/SiO2 material platform for 461 nm operation, show an improvement in focusing efficiencies from ≈ 55% to ≈ 90% at low numerical apertures and from ≈ 35% to ≈ 65% at high numerical apertures. Simulations of ideal and imperfect metalenses indicate that anti‐reflective metasurfaces not only improve transmission at the design library level, but also reduce spurious diffraction and protect against higher‐order scattering. [ABSTRACT FROM AUTHOR]

A 2D geometric analysis of the thin-film crescent-shaped nanostructure array fabrication process based on colloidal lithography was carried out. Calculation formulas are given that allow, at given angles of evaporation (generally, deposition) of a thin metal film through a mask formed by nanospheres deposited on the substrate surface, and its subsequent sputtering (normal or oblique) through the same mask, to find the 2D boundaries of the resulting crescent-shaped nanostructures. The analytical and numerical results obtained make it possible to optimize the specified angles to obtain an array of the thin-film crescent-shaped nanostructures with the required geometric parameters, such as the crescent tip angles and/or the crescent width. [ABSTRACT FROM AUTHOR]

We show how phase-sensitive manipulation of a probe field transmission spectrum can be used to find the precise position of an atom. Our method is based on the controlled superposition of two standing wave fields that move in opposite directions. This causes a change in the probe field transmission spectrum. We can control the number and position of localized peaks in the transmission spectrum by changing the relative phase between the two standing waves. We also show that the shift of localized peaks is greatly influenced by the direction of the wave vector in standing wave fields. Our proposed approach provides us with an efficient method of regulating the precise locations of an atom by using phase shift and direction of the wave vector associated with the standing wave fields. This proposal may have potential applications in nano-lithography, advanced laser cooling technology, and quantum information processing. [ABSTRACT FROM AUTHOR]

Numerous studies have been done to advance the development of efficient, simple, and cheap sensors, especially for glucose, which are important in the pharmaceutical and food industries. The most common sensors and biosensors used today are based on electrochemistry. The novelty of this study is the use of dip‐pen nanolithography (DPN) in order to pattern a mixture of glucose oxidase with PMMA as nanoclusters and develop meta‐chemical surface (MCS), which leads to highly efficient working electrodes with increased detection sensitivity compared to the today‐known glucose sensors (∼1×10-9 ${\sim 1\times 1{0}^{-9}}$ M was detected in the current study). Our novel and important results support the feasibility of using DPN to develop sensors on various electrode surfaces patterned with different active species, especially in systems requiring target substance detection over large concentration ranges. [ABSTRACT FROM AUTHOR]

We outline an approach to fabricate nanoscale artificial quasiperiodic tilings with thermal‐scanning probe lithography. Quasiperiodic tilings such as the Ammann‐Beenker, Square Fibonacci tiling, and Penrose are fabricated and imaged with thermal‐conductance feedback microscopy, followed by electron microscopy. The design implementation, chemical, and physical challenges involved in fabricating such artificial systems using nanolithography are discussed. Additionally, the potential applications of fabricated quasiperiodic tilings are explored. [ABSTRACT FROM AUTHOR]

In this study, a novel method to fabricate highly aligned lamellar nanostructures in a millimeter‐scale large area was demonstrated by directing the self‐assembly of block copolymer (BCP) thin films with a temporary thickness‐gradient micropattern via simple two‐step thermal annealing. In the first step of thermal annealing, the BCP nanostructure is latently guided by a phenomenon known as "geometric anchoring" for the area with a thickness gradient. The second annealing step causes thermal reflow of the height gradient micropattern with a sufficiently large curvature to flatten the micropattern. The shear stress generated by thermal reflow enlarged the grain of the BCP nanostructure, resulting in a highly aligned lamellar pattern over the entire area. Finally, the formation of periodic nanopatterns in large area was ensured by performing grazing‐incidence small‐angle x‐ray scattering. This innovative approach in directing the BCP self‐assembly promotes the fabrication of highly aligned nanostructures in large areas through cost‐effective and simple thermal imprinting method and designed two‐step heat treatment. [ABSTRACT FROM AUTHOR]

Scanning probe lithography (SPL) is a promising technology to fabricate high-resolution, customized and cost-effective features at the nanoscale. However, the quality of nano-fabrication, particularly the critical dimension, is significantly influenced by various SPL fabrication techniques and their corresponding process parameters. Meanwhile, the identification and measurement of nano-fabrication features are very time-consuming and subjective. To tackle these challenges, we propose a novel framework for process parameter optimization and feature segmentation of SPL via machine learning (ML). Different from traditional SPL techniques that rely on manual labeling-based experimental methods, the proposed framework intelligently extracts reliable and global information for statistical analysis to fine-tune and optimize process parameters. Based on the proposed framework, we realized the processing of smaller critical dimensions through the optimization of process parameters, and performed direct-write nano-lithography on a large scale. Furthermore, data-driven feature extraction and analysis could potentially provide guidance for other characterization methods and fabrication quality optimization. [ABSTRACT FROM AUTHOR]

Laser resonators have outputs with Gaussian spatial beam profiles. In laser interference lithography (LIL), using such Gaussian‐shaped beams leads to an inhomogeneous exposure of the substrate. As a result, dimensions of lithography‐defined features vary significantly across the substrate. In most LIL setups, pinholes are used as filters to remove optical noise. Following a concept proposed by Hariharan et al., a phase mask can be added to these pinholes. In theory, this modification results in a more uniform beam profile, and, if applied as spatial filters in LIL, in improved exposure and hence feature size uniformity. Here, the first successful fabrication of such elements is reported on and their use in an LIL setup is demonstrated to reduce feature dimension variations in fabricated devices. [ABSTRACT FROM AUTHOR]

The localization of di-atomic molecules is significantly modified and controlled in a four-levels scheme using probe and standing wave control fields. The study investigates the localization peaks of both single and double di-atomic molecules under different controlling parameters and directions of the driving fields. By altering the directions and phases of the driving fields for standing waves, the localized peaks of di-atomic molecules can be shifted between quadrants. The localization of the two di-atomic molecules is manipulated with precise position and minimum uncertainty measurement within a wavelength domain along, kx and ky plane. The reported molecular resolution is reported to more than λ / 3 × λ / 8 along kx and ky plane. The theoretical investigation shows potential application in nano-lithography and diatomic molecular trapping. [ABSTRACT FROM AUTHOR]

Various stamp materials can significantly affect the filling quality of nanoimprint lithography (NIL). The effects of different stamp materials on the imprinting process were investigated from the angles of residual layer (RL) thickness, contact pressure, and filling proportion. The selection of various stamp materials affects the thickness and uniformity of the RL. Soft stamps (PDMS, PU) leave a thin but uneven RL distribution, while the RL imprinted by hard stamps (Si, Ni) is thicker but more uniform. The contact pressure using soft stamps is relatively more evenly distributed than hard stamps. The uneven distribution of contact pressure leads to poor cavity‐filling proportion, especially for hard stamps. This study offers guidance for choosing proper nanoimprint stamp materials for different NIL applications. [ABSTRACT FROM AUTHOR]

Fused filament fabrication, commonly referred to as 3D printing, is an additive manufacturing method finding plenty of applications nowadays. In contrast, polymer nanopatterning by nanolithographic techniques plays an important role in obtaining functional surfaces and coatings for applications in different fields including micro‐ and nanoelectronics. In spite of their relevance, additive manufacturing and polymer nanolithography have not found yet a common niche to be developed. Although both approaches are oriented to achieve different types of objects, it is shown that the confluence of both technologies can be desirable and potentially convenient. Herein, it is demonstrated that by employing conventional 3D printing, it is possible to fabricate nanostructured polymer surfaces in a relatively simple way by using similar approaches as those used in nanoimprint lithography but without the need for clean room conditions. To do that, a printed‐assisted nanoimprint lithography concept (3DPrANIL) has been tested for different types of polymer and silicon templates. It is demonstrated that a polymeric nanostructured hydrophilic template can be replicated accurately on another polymer rendering a nanostructured surface with enhanced hydrophobicity. The results support 3DPrANIL as novel method to obtain micro‐ and nanostructured surfaces with different functionalities like iridescence and hydrophobicity. [ABSTRACT FROM AUTHOR]

Among the different nanostructures that have been demonstrated as promising materials for various applications, three–dimensional (3D) nanostructures have attracted significant attention as building blocks for constructing high-performance nanodevices because of their unusual mechanical, electrical, thermal, optical, and magnetic properties arising from their novel size effects and abundant active catalytic/reactive sites due to the high specific surface area. Considerable research efforts have been devoted to designing, fabricating, and evaluating 3D nanostructures for applications, including structural composites, electronics, photonics, biomedical engineering, and energy. This review provides an overview of the nanofabrication strategies that have been developed to fabricate 3D functional architectures with exquisite control over their morphology at the nanoscale. The pros and cons of the typical synthetic methods and experimental protocols are reviewed and outlined. Future challenges of fabrication of 3D nanostructured materials are also discussed to further advance current nanoscience and nanotechnology. [ABSTRACT FROM AUTHOR]

Plasmonic optical nanolithography using extraordinary optical transmission through a metallic nanohole mask has been actively applied to the high-resolution fabrication of nanostructures over a large area. Although there have been studies on improving the nanostructure fabrication performance in optical nanolithography, such as on adjustable external gap spacing, additional performance enhancement is required for practical applications and commercialization of large-area and high-resolution nanostructure array fabrication techniques. In this study, we design and apply a plasmonic bull’s eye nanostructured meta-mask to enhance the performance of optical nanolithography. Through simulation results and experimental verification, it is confirmed that advanced optical nanolithography using the bull’s eye nanostructured meta-mask has several merits compared to conventional Talbot lithography using nanoholes: (1) Optical nanolithography using the bull’s eye nanostructured meta-mask effectively fabricates nanopillar arrays even at a shorter exposure time than conventional optical lithography using nanoholes. (2) It is possible to create a large-area nanopillar array with various nanopillar diameters by exposure time control in optical nanolithography using the bull’s eye meta-mask. (3) Using water or objective immersion oil to increase the refractive index of the contact medium, light can be focused on smaller sizes, and large-area nanopillar arrays with smaller nanopillar diameters are established. With the upgradation of hardware for large-area fabrication, application of immersion media supplying techniques, and additional studies to establish complex nanostructures, optical nanolithography using the bull’s eye nanostructured meta-mask is an efficient modality to produce various nanostructure-based devices.

Proton beam writing is a promising lithography method that is being developed in many countries. This method has significant advantages over other lithography methods, amongst all, there is the absence of the need for prefabricated pattern masks and a high aspect ratio of fabricated structures. Numerous publications demonstrate prospective applications of proton beam writing in different fields related to micro- and nanostructures fabrication. Proton beam writing may be used both for nanoelectronics and three-dimensional microstructures with a high aspect ratio. Work on proton beam writing technology is being conducted at the Institute of Applied Physics of the National Academy of Sciences of Ukraine. Last years there were introduced vector proton beam writing method, an electrostatic blanker system for proton beam distortion, and experiments on proton beam writing on chitosan films were conducted, including the films covered with thin films of metals and metal compounds.

The combination of area-selective deposition (ASD) with a patternable organic monolayer provides a versatile additive lithography platform, enabling the generation of a variety of nanoscale feature geometries. Stearate hydroxamic acid self-assembled monolayers (SAMs) were patterned with extreme ultraviolet (λ = 13.5 nm) or electron beam irradiation and developed with ASD to achieve line space patterns as small as 50 nm. Density functional theory was employed to aid in the synthesis of hydroxamic acid derivatives with optimized packing density to enhance the imaging contrast and improve dose sensitivity. Near-edge X-ray absorption fine structure spectroscopy and infrared spectroscopy reveal that the imaging mechanism is based on improved deposition inhibition provided by the cross-linking of the SAM to produce a more effective barrier during a subsequent deposition step. With patterned substrates composed of coplanar copper lines and silicon spacers, hydroxamic acids selectively formed monolayers on the metal portions and could undergo a pattern-wise exposure followed by ASD in the first combination of a patternable monolayer with ASD. This material system presents an additional capability compared to traditional ASD approaches that generally reflect a starting patterned surface. Furthermore, this bottoms-up additive approach to lithography may be a viable alternative to subtractive nanoscale feature generation.

Micromagnetic computations were performed to predict the magnetisation maps in thin elliptically shaped nanoparticles under a variable external magnetic field. Two materials were compared as the constituents of the nanoparticles: permalloy as an example of an isotropic magnet and cobalt, i.e., a hard magnetic material marked with a single easy axis. The interplay of the shape and magnetocrystalline anisotropy gives rise to a variety of switching scenarios, which may be of interest in designing memory storage devices. A fairly periodic shape-induced superlattice-like spin configuration occurs when the shape and magnetocrystalline easy axes are orthogonal. Possible applications as magnonic devices are discussed.

Femtosecond laser processing is widely adopted today for microfabrication because of its ability to make rapid processing on almost all types of materials in ambient environment. However, it is challenging to apply femtosecond lasers for high-speed large-scale subwavelength nanofabrication, particularly, for two-dimensional nanopatterning on transparent dielectric materials due to their low light absorption. Previous demonstrations of femtosecond laser two-dimensional nanofabrication on dielectrics typically lack structural quality and long-range uniformity. In this work, we report a maskless laser nano-lithographic technique to fabricate high-quality two-dimensional periodic nanodomes on glass. The glass sample is first coated with a thin copper film and then irradiated by femtosecond laser pulses. We show that the period and size of the nanodomes can be controlled using a multi-fluence process. More importantly, a single-fluence technique is developed here, for the first time, for high-quality nanopatterning on glass. The nanopatterning formation mechanism is studied by dynamics experiments and numerical simulations. This introduced technique will provide a simple but highly effective way for dielectrics nanofabrication. [ABSTRACT FROM AUTHOR]

Laser resonators have outputs with Gaussian spatial beam profiles. In laser interference lithography (LIL), using such Gaussian‐shaped beams leads to an inhomogeneous exposure of the substrate. As a result, dimensions of lithography‐defined features vary significantly across the substrate. In most LIL setups, pinholes are used as filters to remove optical noise. Following a concept proposed by Hariharan et al., a phase mask can be added to these pinholes. In theory, this modification results in a more uniform beam profile, and, if applied as spatial filters in LIL, in improved exposure and hence feature size uniformity. Here, the first successful fabrication of such elements is reported on and their use in an LIL setup is demonstrated to reduce feature dimension variations in fabricated devices.

Abstract Various stamp materials can significantly affect the filling quality of nanoimprint lithography (NIL). The effects of different stamp materials on the imprinting process were investigated from the angles of residual layer (RL) thickness, contact pressure, and filling proportion. The selection of various stamp materials affects the thickness and uniformity of the RL. Soft stamps (PDMS, PU) leave a thin but uneven RL distribution, while the RL imprinted by hard stamps (Si, Ni) is thicker but more uniform. The contact pressure using soft stamps is relatively more evenly distributed than hard stamps. The uneven distribution of contact pressure leads to poor cavity‐filling proportion, especially for hard stamps. This study offers guidance for choosing proper nanoimprint stamp materials for different NIL applications.

Organic—inorganic hybrid perovskites have attracted considerable attention for developing novel optoelectronic devices owing to their excellent photoresponses. However, conventional nanolithography of hybrid perovskites remains a challenge because they undergo severe damage in standard lithographic solvents, which prohibits device miniaturization and integration. In this study, a novel transparent stencil nanolithography (t‐SL) technique is developed based on focused ion beam (FIB)‐assisted polyethylene terephthalate (PET) direct patterning. The proposed t‐SL enables ultrahigh lithography resolution down to 100 nm and accurate stencil mask alignment. Moreover, the stencil mask can be reused more than ten times, which is cost‐effective for device fabrication. By applying this lithographic technique to hybrid perovskites, a high‐performance 2D hybrid perovskite heterostructure photodetector is fabricated. The responsivity and detectivity of the proposed heterostructure photodetector can reach up to 28.3 A W−1 and 1.5 × 1013 Jones, respectively. This t‐SL nanolithography technique based on FIB‐assisted PET direct patterning can effectively support the miniaturization and integration of hybrid‐perovskite‐based electronic devices. [ABSTRACT FROM AUTHOR]

Laser exposure defines voxel's dimensions as essential building blocks in direct write 3D nanolithography. However, the exposure conditions not only influence the size of the produced features but also their optical properties. This empowers the realization of an adjustable refractive index out of single material by varying the writing strategy while preserving laser 3D nanolithography's flexibility in geometry and high resolution. Here, the refractive index for the 450–1600 nm spectral range of the micro‐optics out of SZ2080 hybrid polymer is systematically studied by applying ray and wave optics approaches followed by optical resolution analysis. It reveals the exact value of the laser‐printed components instead of the determination assessed by other techniques measuring thin films or bulky volumes of the investigated substance. The studied micro‐lenses are of below 100 µm in dimensions and a clear distinction in their performance on low and high exposure doses is found by analyzing it in all different approaches and validating using different lithography setups. Findings reveal the complexity of the refractive index of the 3D micro‐optics which is influenced by the material density and morphology. A route for freedom in 3D printing shape and refractive index can be realized by the technological optimization of delicate exposure control in ultrafast laser nanolithography. [ABSTRACT FROM AUTHOR]

Micro/nano patterns based on quantum dots (QDs) are of great interest for applications ranging from electronics to photonics to sensing devices for biomedical purposes. Several patterning methods have been developed, but all lack the precision and reproducibility required to fabricate precise, complex patterns of less than one micrometer in size, or require specialized crosslinking ligands, limiting their application. In this study, we present a novel approach to directly pattern QD nanopatterns by electron beam lithography using commercially available colloidal QDs without additional modifications. We have successfully generated reliable dot and line QD patterns with dimensions as small as 140 nm. In addition, we have shown that using a 10 nm SiO2 spacer layer on a 50 nm Au layer substrate can double the fluorescence intensity compared to QDs on the Au layer without SiO2. This method takes advantage of traditional nanolithography without the need for a resist layer. [ABSTRACT FROM AUTHOR]

Near-perfect light absorbers (NPLAs), with absorbance, A , of at least 99%, have a wide range of applications ranging from energy and sensing devices to stealth technologies and secure communications. Previous work on NPLAs has mainly relied upon plasmonic structures or patterned metasurfaces, which require complex nanolithography, limiting their practical applications, particularly for large-area platforms. Here, we use the exceptional band nesting effect in TMDs, combined with a Salisbury screen geometry, to demonstrate NPLAs using only two or three uniform atomic layers of transition metal dichalcogenides (TMDs). The key innovation in our design, verified using theoretical calculations, is to stack monolayer TMDs in such a way as to minimize their interlayer coupling, thus preserving their strong band nesting properties. We experimentally demonstrate two feasible routes to controlling the interlayer coupling: twisted TMD bi-layers and TMD/buffer layer/TMD tri-layer heterostructures. Using these approaches, we demonstrate room-temperature values of A =95% at λ=2.8 eV with theoretically predicted values as high as 99%. Moreover, the chemical variety of TMDs allows us to design NPLAs covering the entire visible range, paving the way for efficient atomically-thin optoelectronics. The authors demonstrate near-perfect light absorption using only two atomic layers of transition metal dichalcogenides. This is achieved by reducing interlayer interaction which optimizes band nesting, and does not require the use of complex metasurfaces. [ABSTRACT FROM AUTHOR]