Search

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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.

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.

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]

This paper proposes two different approaches to studying resistive switching of oxide thin films using scratching probe nanolithography of atomic force microscopy (AFM). These approaches allow us to assess the effects of memristor size and top-contact thickness on resistive switching. For that purpose, we investigated scratching probe nanolithography regimes using the Taguchi method, which is known as a reliable method for improving the reliability of the result. The AFM parameters, including normal load, scratch distance, probe speed, and probe direction, are optimized on the photoresist thin film by the Taguchi method. As a result, the pinholes with diameter ranged from 25.4 ± 2.2 nm to 85.1 ± 6.3 nm, and the groove array with a depth of 40.5 ± 3.7 nm and a roughness at the bottom of less than a few nanometers was formed. Then, based on the Si/TiN/ZnO/photoresist structures, we fabricated and investigated memristors with different spot sizes and TiN top contact thickness. As a result, the HRS/LRS ratio, USET, and ILRS are well controlled for a memristor size from 27 nm to 83 nm and ranged from ~8 to ~128, from 1.4 ± 0.1 V to 1.8 ± 0.2 V, and from (1.7 ± 0.2) × 10−10 A to (4.2 ± 0.6) × 10−9 A, respectively. Furthermore, the HRS/LRS ratio and USET are well controlled at a TiN top contact thickness from 8.3 ± 1.1 nm to 32.4 ± 4.2 nm and ranged from ~22 to ~188 and from 1.15 ± 0.05 V to 1.62 ± 0.06 V, respectively. The results can be used in the engineering and manufacturing of memristive structures for neuromorphic applications of brain-inspired artificial intelligence systems. [ABSTRACT FROM AUTHOR]

In Moiré fringe lithography alignment technology, alignment is realized by monitoring the grating interference fringe image in real-time. The technique exhibits excellent sensitivity to displacement changes and is not easily affected by the gap changes between the mask and silicon wafer. Therefore, this technique is widely used in conventional proximity and contact lithography and new-generation micro- and nanolithography systems. The rapid development of semiconductor and integrated circuit industries, as well as the increasing requirements for the resolution of various nanodevices and systems, have posed new challenges in Moiré fringe lithography alignment technology, which are mainly reflected in alignment accuracy, alignment range, and scheme complexity. In this study, the development history, alignment principle, and overall process of Moiré fringe lithography alignment technology are reviewed; the main factors affecting alignment accuracy are analyzed, and corresponding optimization schemes are provided; and finally, the development trend and research focus of Moiré fringe lithography alignment technology are predicted from the marking structure, alignment scheme, and algorithm processing. [ABSTRACT FROM AUTHOR]

The fabrication of three-dimensional (3D) nanostructures within optical materials is currently a highly sought-after capability. Achieving nanoscale structuring of media within its inner volume in 3D and with free design flexibility, high accuracy and precision is a development yet to be demonstrated. In this work, a 3D laser nanolithography technique is developed which allows producing mm-long hollow nanopores inside solid-state laser crystals and with a high degree of control of pore cross-sectional aspect ratio and size. We report an in-depth study on the formation of pores both within the non-thermal regime at which temperature is fast dissipated after each laser pulse, and for a thermally controlled regime using pulse-bursts which facilitate the formation of pores with highly circular shapes down to 1.1. We demonstrate this process for a wide range of speeds, pulse repetition rates and pulse energies, thus opening the door to a much more useful nanofabrication technique for nanophotonics. Finally, we also report the change in index of refraction that is produced at the nanoscale obtaining a positive index contrast of ∼3%. The work therefore provides a promising path towards reliable 3D nanostructuring of solid-state laser media for the flexible fabrication of large and complex structures with features sizes from the nanoscale up to the mm-scale. Moreover, due to the embedded, seamless, and monolithic nature of this technology, and since YAG crystals can sustain temperatures of up to 1900 °C and are highly chemically inert and erosion resistant, we anticipate its direct application in harsh environments. [ABSTRACT FROM AUTHOR]

Multiphoton photopolymerisation (MPP), also known as 3D nanoprinting, was studied using a wavelength-tunable femtosecond laser. The possibility of using any colour of the spectrum from 500 to 1200 nm with a fixed pulse width of 100 fs revealed an interplay of photophysical mechanisms more delicate than just two-photon photopolymerisation. An effective order of absorption, i.e. the X-photon absorption, as well as optimal exposure conditions were assessed for photosensitised and pure SZ2080TM pre-polymer. The tunability of wavelength greatly influenced the dynamic fabrication window (DFW), optimised conditions resulting in a 10-fold increase. Furthermore, a non-trivial energy deposition by X-photon absorption was noted with an onset of a strong lateral size increase at longer wavelengths and can be understood as due to reaching epsilon-near-zero conditions. Such a control over the voxel aspect ratio and, consequently, the photopolymerised volume, may boost 3D nanoprinting efficiency. Overall, the results reveal wavelength being an important degree of freedom to tailor the MPP process and, if optimised, benefiting broad applications in areas of micro-optics, nanophotonic devices, metamaterials and tissue engineering. [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.

Localized actuation is an important goal of nanotechnology broadly impacting applications such as programmable materials, soft robotics, and nanolithography. Despite significant recent advances, actuation with high temporal and spatial resolution remains challenging to achieve. Herein, we demonstrate strongly localized photoactuation of polymer pens made of polydimethylsiloxane (PDMS) and surface-functionalized short carbon nanotubes based on a fundamental understanding of the nanocomposite chemistry and device innovations in directing intense light with digital micromirrors to microscale domains. We show that local illumination can drive a small group of pens (3 × 3 over 170 μm × 170 μm) within a massively two-dimensional array to attain an out-of-plane motion by more than 7 μm for active molecular printing. The observed effect marks a striking three-order-of-magnitude improvement over the state of the art and suggests new opportunities for active actuation. [ABSTRACT FROM AUTHOR]

The infrared band is one of the important communication windows. Most of the detectors and sensors working in this band are designed and manufactured based on micro- and nano-lithography technology. In this article, we cut the giant-sized thickness of the transparent substrate and the metal film was uniformly sliced. Then, we used the CST software to simulate the sliced substrate and the metal film to obtain the optical response parameters for each slice. Finally, the combination of metal film and substrate was realized by cascading calculation of the two port transmission line theory, which solves problems such as overlong simulation time and cumbersome running load caused by huge grid divisions due to the difference between the substrate thickness and the response wavelength in the process of simulating light propagation. On the other hand, the cascade analysis method was experimentally verified by constructing a surface plasmon filter in the medium infrared band, which provides an effective idea and solution for bridging the gap between simulation and engineering application. [ABSTRACT FROM AUTHOR]

In this study, we investigated the ferroelectric domain wall current corresponding to the ferroelectric domain structures of BaTiO 3 (BTO) nanodots deposited on Nb-doped SrTiO 3 substrates using the dip-pen nanolithography (DPN) method. By controlling the DPN deposition time, the deposited BTO nanodots with a diameter of 60–200 nm were crystallized by heat treatment at 800°C. The ferroelectric domain structures of BTO nanodots were observed through piezoresponse force microscope studies, and the formation of domain walls was observed. Relatively large ferroelectric domain wall currents formed on the ferroelectric domain wall produced by BTO nanodots and currents corresponding to the ferroelectric polarization direction around the domain wall were observed through a conducting atomic force microscope. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In modern extreme ultraviolet (EUV) lithography machines, sensitive optical components, such as multilayer mirrors and photomasks, may be affected by plasma interactions. The new 13.5 nm EUV-beam-line 2, designed to provide accelerated tests for next generation lithography, is used to investigate EUV-induced plasma phenomena. First systematic measurements of ion fluxes produced in EUV-induced hydrogen plasma are reported, with operating conditions including 5 and 20 Pa gas pressure, 3 kHz EUV pulse repetition rate, and 4.2 W total EUV beam power produced in a 10–15 ns EUV pulse. Space- and time-resolved distributions of ion fluxes and ion energies were measured using a retarding-field ion energy analyzer mounted next to the EUV beam. Typical ion energies were in the range of 1–8 eV and typical ion fluxes were in the range of 2–8 × 1017 ions m−2 s−1. The obtained ion fluxes are applied in a photomask lifetime test to understand the material effects after an EUV exposure. [ABSTRACT FROM AUTHOR]

In recent years, Atomic Force Microscope (AFM)-based nanolithography techniques have emerged as a very powerful approach for the machining of countless types of nanostructures. However, the conventional AFM-based nanolithography methods suffer from low efficiency, low rate of patterning, and high complexity of execution. In this frame, we first developed an easy and effective nanopatterning technique, termed Pulse-Atomic Force Lithography (P-AFL), with which we were able to pattern 2.5D nanogrooves on a thin polymer layer. Indeed, for the first time, we patterned nanogrooves with either constant or varying depth profiles, with sub-nanometre resolution, high accuracy, and reproducibility. In this paper, we present the results on the investigation of the effects of P-AFL parameters on 2.5D nanostructures' morphology. We considered three main P-AFL parameters, i.e., the pulse's amplitude (setpoint), the pulses' width, and the distance between the following indentations (step), and we patterned arrays of grooves after a precise and well-established variation of the aforementioned parameters. Optimizing the nanolithography process, in terms of patterning time and nanostructures quality, we realized unconventional shape nanostructures with high accuracy and fidelity. Finally, a scanning electron microscope was used to confirm that P-AFL does not induce any damage on AFM tips used to pattern the nanostructures. [ABSTRACT FROM AUTHOR]

Optical antennas play an important role in optical field manipulation. Among them, nanoscale bowtie antennas have been extensively studied for its high confinement and enhancement. In this mini-review, we start with a brief introduction of bowtie antennas and underlying physics. Then we review the applications with respect to optically and electrically excited nanoscale bowtie antennas. Optically driven bowtie antennas enable a set of optical applications such as near-field imaging/trapping, nonlinear response, nanolithography, photon generation and detection. Finally, we put emphasis on the principle and applications of electrically driven bowtie antennas, an emerging method of generating ultrafast and broadband tunable nanosources. In a word, nanoscale bowtie antennas still have great potential research value to explore.

Abstract Thermal scanning probe lithography is a direct‐write patterning method that uses a heated scanning probe tip to remove thermal resist. The most widely used thermal resist is polyphthalaldehyde. Another alternative thermal resist, Parylene C is introduced in this letter. It has been found that Parylene C has a wide process latitude as a thermal resist under our experimental conditions. A high resolution of ∼40 nm can be achieved in our optimised process. In addition, patterns in parylene layer can be transferred directly into the substrate with deep reactive ion etching without an additional hard mask, thus simplifying the fabrication process.

The article "Ultrafast Laser Manipulation of In‐Lattice Plasmonic Nanoparticles" published in Advanced Science discusses the challenges of producing hybrid plasmonic materials on single‐crystalline substrates to achieve exceptional optical properties. Authors Saulius Juodkazis, Feng Chen, and colleagues present an innovative in‐lattice plasmonic nanolithography process for functional crystals, successfully fabricating nanorods with robust polarization selectivity within the lattice. This approach has the potential to create customized micro‐nano photonic structures and devices with exceptional properties in functional materials and single‐crystal films. [Extracted from the article]

The paper describes nanometer scale lithography on atomically clean Ge(111)-c(2x8) surface performed in the ultra-high vacuum scanning tunneling microscope operating at 300 K. Using a standard Pt80Ir20 probe tip and applying bias voltages between 0.5 and 3 V, the Ge surface could be reliably imaged with atomic resolution without any modification of the sample. However, surface modification in highly localized area under the probe tip was observed at the bias voltages from 4 to 5 V. Such modification could occur in the form of the deposition of the tip material onto the scanned area of the sample, extraction of the sample material or generation of defects in the sample crystalline structure. Possible physical mechanisms of the processes outlined above as well as the strategies to achieve reliable scanning probe nanolithography are discussed. [ABSTRACT FROM AUTHOR]

The commercialized binder carboxymethyl cellulose sodium (CMC‐Na) is considered unsuitable for micro‐sized SiOx anode as it cannot endure the large volume change to retain the conductive network during repeated charge/discharge cycles. Herein, a small amount of silicon nanoparticles (SiNPs) is added during slurry preparation process as "nano‐combs" to unfold the convoluted CMC‐Na polymer chains so that they undergo a coil‐to‐stretch transition by interaction between polar groups (e.g., –OH, –COONa) of polymer and SiNPs' large surface. Through maximizing the utilization of binders, a uniform conductive network is constructed with increased interfacial contact with micro‐sized SiOx. As a result, the SiOx electrode with optimized (10 wt%) SiNPs addition shows significantly improved initial capacity and cycling performance. Through revisiting CMC‐Na, a currently deemed unqualified binder in SiOx anode, this work gives a brand‐new perspective on the failing mechanism of Si‐based anode materials and an improving strategy for electrode preparation. [ABSTRACT FROM AUTHOR]

Laser direct-writing enables micro and nanoscale patterning, and is thus widely used for cutting-edge research and industrial applications. Various nanolithography methods, such as near-field, plasmonic, and scanning-probe lithography, are gaining increasing attention because they enable fabrication of high-resolution nanopatterns that are much smaller than the wavelength of light. However, conventional methods are limited by low throughput and scalability, and tend to use electron beams or focused-ion beams to create nanostructures. In this study, we developed a procedure for massively parallel direct writing of nanoapertures using a multi-optical probe system and super-resolution near-fields. A glass micro-Fresnel zone plate array, which is an ultra-precision far-field optical system, was designed and fabricated as the multi-optical probe system. As a chalcogenide phase-change material (PCM), multiple layers of Sb65Se35 were used to generate the super-resolution near-field effect. A nanoaperture was fabricated through direct laser writing on a large-area (200 × 200 mm2) multi-layered PCM. A photoresist nanopattern was fabricated on an 8-inch wafer via near-field nanolithography using the developed nanoaperture and an i-line commercial exposure system. Unlike other methods, this technique allows high-throughput large-area nanolithography and overcomes the gap-control issue between the probe array and the patterning surface. [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.

In this era, electronic devices such as mobile phones, computers, laptops, sensors, and many more have become a necessity in healthcare, for a pleasant lifestyle, and for carrying out tasks quickly and easily. Different types of temperature sensors, biosensors, photosensors, etc., have been developed to meet the necessities of people. All these devices have chips inside them fabricated using diodes, transistors, logic gates, and ICs. The patterning of the substrate which is used for the further development of these devices is done with the help of a technique known as lithography. In the present work, we have carried out a review on different types of lithographic techniques such as optical lithography, extreme ultraviolet lithography, electron beam lithography, X-ray lithography, and ion beam lithography. The evolution of these techniques with time and their application in device fabrication are discussed. The different exposure tools developed in the past decade to enhance the resolution of these devices are also discussed. Chemically amplified and non-chemically amplified resists with their bonding and thickness are discussed. Mask and maskless lithography techniques are discussed along with their merits and demerits. Device fabrication at micro and nano scale has been discussed. Advancements that can be made to improve the performance of these techniques are also suggested. [ABSTRACT FROM AUTHOR]

Nanopatterns formed by dense nanoscale (20–30nm diameter) block copolymer lithography and subsequent selective area MOVPE were utilized to realize room temperature operation of quantum dot (QD) active region laser diodes on InP substrates, by employing a carrier-injection layer adjacent to the QDs. Initial studies focused on InGaAs QDs grown on GaAs substrates, which exhibit relatively broad photoluminescence (PL) emission linewidths (FWHM~93meV at RT). Atomic force microscopy measurements reveal that a wide distribution of QD thickness variations correlates well to the observed broad PL linewidths, based on the simulated range of QD transitions. The fabricated edge-emitting devices on InP substrate exhibit lasing emission near $1.57\sim 1.67~\mu \text{m}$ at room temperature with a threshold current density as low as 1.6 kA/cm2 for 4mm-long devices. The observed dependency of device characteristics, such as threshold current density and lasing wavelength, on the cavity length and on the heat sink temperature suggests the dominant lasing transition energy corresponds to the QD excited state, except for the longest cavity length devices (L = 4mm) which operate on the QD ground state transition near room temperature. We believe these data represent the only reports of lasers in this wavelength region employing QDs formed by diblock co-polymer lithography and selective area MOVPE growth. These data also suggest that QD height variations need to be further reduced, through MOVPE growth optimization, to achieve higher optical gain from the QD ground state transition. [ABSTRACT FROM AUTHOR]

With the development and progress of nanotechnology, the prospect of using nanorobots to achieve targeted drug delivery is becoming possible. Although nanorobots can potentially improve nano-drug delivery systems, there remains a significant challenge to fabricating magnetically controllable nanorobots with a size suitable for drug delivery in complex in vivo environments. Most of the current research focused on the preparation and functionalization of microscale and milliscale robots due to the relative difficulties in fabricating nanoscale robots. To address this problem and move towards in vivo applications, this study uses electron beam lithography to fabricate achiral planar L-shaped nanorobots that are biocompatible with immune cells. Their minimal planar geometry enabled nanolithography to fabricate nanorobots with a minimum feature size down to 400 nm. Using an integrated imaging and control system, the locomotive behavior of the L-shaped nanorobots in a fluidic environment was studied by examining their velocity profiles and trajectories. Furthermore, the nanorobots exhibit excellent cell compatibility with various types of cells, including macrophage cells. Finally, the long-term cell culture medium immersion test demonstrated that the L-shaped nanorobots have robust stability. This work will demonstrate the potential to use these nanorobots to operate in vivo without triggering immune cell responses. [ABSTRACT FROM AUTHOR]

Abstract The feature size in Integrated Circuits (ICs) has been scaling down aggressively, thereby posing more challenges in their manufacturability. Conventional immersion lithography using a laser of 193 nm wavelength produces layouts having distortions that degrade performance significantly. To overcome this bottleneck, Next‐Generation Lithography (NGL) technologies are being developed. Extreme Ultraviolet Lithography (EUVL), one of the popular NGLs, which uses a light of 13.5 nm wavelength. However, irregularities on the photo reflective surface of clear‐field masks used in EUVL, scatter the incident light and cause flare that in turn results in layout pattern distortions and critical dimension (CD) violations. One of the approaches to counter the effect of flare is to utilise dummy metal fills. But this incurs additional mask cost. Herein, a method to reduce the flare variation as well as the average flare distribution for a layout by perturbation of wire segments, without affecting performance at the post‐layout phase, is proposed. The results show reductions of 20% and 11% on an average in the flare variation and flare mean, respectively, compared to that for the original layout for two different flare models studied on three standard sets of benchmark suites. Consequently, a reduction in the dummy fill demand of a similar magnitude is thus obtained.