Nanoscale Manufacturing Research Articles

Recent advances in focused ion beam nanofabrication for nanostructures and devices: fundamentals and applications.

The past few decades have witnessed growing research interest in developing powerful nanofabrication technologies for three-dimensional (3D) structures and devices to achieve nano-scale and nano-precision manufacturing. Among the various fabrication techniques, focused ion beam (FIB) nanofabrication has been established as a well-suited and promising technique in nearly all fields of nanotechnology for the fabrication of 3D nanostructures and devices because of increasing demands from industry and research. In this article, a series of FIB nanofabrication factors related to the fabrication of 3D nanostructures and devices, including mechanisms, instruments, processes, and typical applications of FIB nanofabrication, are systematically summarized and analyzed in detail. Additionally, current challenges and future development trends of FIB nanofabrication in this field are also given. This work intends to provide guidance for practitioners, researchers, or engineers who wish to learn more about the FIB nanofabrication technology that is driving the revolution in 3D nanostructures and devices.

Special Issue on Advances in Micro- and Nano-Manufacturing

This Special Issue contains selected papers presented at the Advances in Micro- and Nano-Manufacturing—Kornel Ehmann Symposium at 2020 ASME International Manufacturing Science and Engineering Conference (MSEC). The symposium was cosponsored by the SME North American Manufacturing Research Institution (NAMRI). This symposium is dedicated to Prof. Kornel F. Ehmann for his visionary leadership and profound impact on the field.Micro- and nano-scale manufacturing is gaining more attention due to production miniaturization and customization. High precision and product quality are difficult to achieve at this length scale; thus, a deeper understanding of the processes, development of characterization methods, modeling and simulations, and monitoring are required for the improvement of product quality. This collection of papers presents the latest advances in micro- and nano-manufacturing technologies that enhance both theoretical and experimental understandings, as well as bring application-oriented innovations.The collection of papers covers an array of microprocesses, including micro-machining, molding, forming, extrusion, and additive processes. The most represented one is still the subtractive process, but the dominant material removal mechanisms are diversely distributed, including traditional tool-based milling, electrical discharge machining (EDM), electrical chemical machining (ECM), laser machining, etc. New theoretical understandings of process mechanics and material responses at the microscale have been provided through advanced simulation techniques (molecular dynamic simulation) and new experimental tools (X-ray imaging). The findings reveal the unique phenomenon of microstructural evolution, energy consumption, material hardening during micro-manufacturing processes. Some interesting applications have also been demonstrated to highlight the innovations in micromanufacturing. Particularly, structural colorization was achieved through nonisothermal precision glass molding. Microelectrode arrays were sharpened by laser machining for brain recording. Optical fiber sensors were fabricated by laser ablation.The Guest Editor would like to thank the authors for their contributions and prompt efforts in preparing their papers, as well as the reviewers for their timely assistance. Special thanks also go to the co-organizers of the Advances in Micro- and Nano-Manufacturing Symposium, Dr. Martin Jun from Purdue University, and Dr. Chandra Nath from Maijker Corp. The symposium has attracted the highest number of submissions among all symposiums at the 2020 MSEC and won the Best Organizer of Symposium & Sessions Award. Finally, we thank the ASME Journal of Micro- and Nano-Manufacturing Editor, the Editorial Office, and the ASME Production Team for their encouragement and assistance during the preparation of this Special Issue.

Nanoscale manufacturing as an enabling strategy for the design of smart food packaging systems

Abstract Nanoscale manufacturing has enabled the development of smart packaging systems for the functional and convenient distribution of food products, overcoming the major bottlenecks to the future fabrication of stable, safe, economically feasible, and environmentally friendly food packaging systems. Traditionally, packaging systems have been used to protect products from physical impacts and were designed mainly for storage and transportation. The more recent packaging systems carry out the many additional functions required to maintain, preserve, and sustain the food product. In this review, we describe two nanoscale manufacturing-based approaches (viz., nanomaterials and nanofabrication) for smart food packaging systems and focus on their performance, including their gas barrier, antibacterial, and protective effects. Looking to the future, we summarize the updated information on the incorporation of nanoscale manufacturing-based systems into the food industry and discuss new perspectives of these systems for the smart food packaging industry.

Trapping of sub-wavelength microparticles and cells in resonant cylindrical shells

Acoustic tweezers based on the focused field hold the promise of contactless manipulation of microparticles. However, acoustic diffraction severely limits the trapping strength and the minimum size of the trapped particles in conventional diffraction-limited systems. Here, we propose and demonstrate a simple cylindrical shell structure for the trapping of microparticles with a radius as small as 1/400 of the corresponding acoustic wavelength, and its trapping ability is much stronger than that of the standing wave. This mechanism is attributed to the significantly enhanced acoustic radiation force originating from the resonant excitation of low order circumferential modes intrinsically existing in the cylindrical shell, which is a highly localized field around its surfaces. Cylindrical shell-based acoustic tweezers are simple, disposable, low cost, biocompatible, and functional, which may be of interest for nano-scale manufacturing and biomedical applications such as bio-printing, cell culturing, and tissue engineering.

Multiscale Assessment of Nanoscale Manufacturing Process on the Freeform Copper Surface.

The nanocutting has been paid great attention in ultra-precision machining and high sealing mechanical devices due to its nanometer level machining accuracy and surface quality. However, the conventional methods applicable to reproduce the cutting process numerically such as finite element (FE) and molecular dynamics (MD) are challenging to unveil the cutting machining mechanism of the nanocutting due to the limitation of the simulation scale and computational cost. Here a modified quasi-continuous method (QC) is employed to analyze the dynamic nanocutting behavior (below 10 nm) of the copper sample. After preliminary validation of the effectiveness via the wave propagation on the copper ribbon, we have assessed the effects of cutting tool parameters and back-engagement on the cutting force, stress distribution and surface metamorphic layer depth during the nanocutting process of the copper sample. The cutting force and depth of the surface metamorphic layer is susceptible to the back-engagement, and well tolerant to the cutting tool parameters such as the tool rank angle and tool rounded edge diameter. The results obtained by the QC method are comparable to those from the MD method, which indicate the effectiveness and applicability of the modified QC method in the nanocutting process. Overall, our work provides an applicable and efficient strategy to investigate the nanocutting machining mechanism of the large-scale workpiece and shed light on its applications in the super-precision and high surface quality devices.

Comparative Study of Optical Silicon Nanomachining Experimental Results and MD Simulation Outputs

The high strength and good optical performance offered by optical grade silicon could be considered as the reason for its wide usage as optical materials in many industries including electronic, metrology, infrared (IR) optics and solar cells. Due to this, nanoscale manufacturing of these products requires superior quality and enhanced functional performance of the produced materials. Because recent studies have been focusing on correlating both surface and subsurface nature alterations with better functional performance, an MD study of the experiment was carried out in comparison with experiment to match the observed MD model features to the experimental result obtained. The MD study was observed to conform with the Ra result as obtained in the experiment.

Low-temperature chemical vapor deposition growth of graphene films enabled by ultrathin alloy catalysts

This report introduces a method for fabricating graphene at low temperatures via chemical vapor deposition enabled by ultrathin (∼1 nm) nickel-gold (Ni-Au) catalysts. The unique combination of high carbon (C) solubility Ni, low C solubility Au, and an ultrathin layer of a catalyst demonstrates the effectiveness to produce graphene at 450 °C with the layer number independent of growth duration. In contrast to grain-boundary defined catalyst morphology found in thicker (>20 nm) metal catalysts, the ultrathin catalyst morphology leads to the formation of nanoscale metal “islands” during the growth process, which results in curved graphene covering the catalyst. To test the effect of preactivation of the ultrathin catalyst for the formation of graphene, a preanneal process of the catalyst followed by the introduction of a carbon precursor was also investigated. The preanneal process resulted in the formation of carbon nanotubes (CNTs) in lieu of graphene, displaying the impact of the catalytic surface treatment in relation to the produced materials. The results and discussion presented here detail a low-temperature nanoscale manufacturing process that allows for the production of either graphene or CNTs on an ultrathin catalyst.

Directional Assembly of Nanoparticles by DNA Shapes: Towards Designed Architectures and Functionality.

In bottom-up self-assembly, DNA nanotechnology plays a vital role in the development of novel materials and promises to revolutionize nanoscale manufacturing technologies. DNA shapes exhibit many versatile characteristics, such as their addressability and programmability, which can be used for determining the organization of nanoparticles. Furthermore, the precise design of DNA tiles and origami provides a promising technique to synthesize various complex desired architectures. These nanoparticle-based structures with targeted organizations open the possibility to specific applications in sensing, optics, catalysis, among others. Here we review progress in the development and design of DNA shapes for the self-assembly of nanoparticles and discuss the broad range of applications for these architectures.

Cancer Nanotechnology in Medicine: A Promising Approach for Cancer Detection and Diagnosis

Despite extraordinary advances that have been made in cancer therapy, the number of cancer cases continue to surge, making it the leading cause of death across the world. As a result, early detection is one of the key aspects in the battle against the disease. Screening and early diagnosis play a pivotal role for effective treatment and to lower the cancer mortality rate. Cancer nanotechnology is a new branch in biology that provides a link between nanotechnology and clinical cancer research. Moreover, it also aims to integrate the advancements made in the manufacture of nanoscale devices with cellular and molecular components associated with cancer diagnosis and therapy. Understanding these new technologies is crucial to integrating these practices into clinical settings. This novel approach has facilitated the conjugation of nanoscale devices with agents such as tumor-specific li-gands, antibodies, and imaging probes. This review summarizes the advancements made in nanotechnology based approaches in diagnosing cancer. Coupling of nanoparticles with targeting molecules enables an efficient interaction between biological systems with extraordinary accuracy. The progress associated with nanoscale devices such as metal based nanomaterials, exosomes, magnetic nanoparticles, in addition to quantum dots and lab on chip devices with regard to diagnostic applications has been discussed. We summarize how nanoparticles take advantage of the tumor microenvironment for targeting cancer cells. Further, the review outlines the drawbacks, challenges, and future prospects associated with these techniques as effective strategies to replace current clinical trends.

Nanoscale dynamic chemical, biological sensor material designs for control monitoring and early detection of advanced diseases.

Early detection and easy continuous monitoring of emerging or re-emerging infectious, contagious or other diseases are of particular interest for controlling healthcare advances and developing effective medical treatments to reduce the high global cost burden of diseases in the backdrop of lack of awareness regarding advancing diseases. Under an ever-increasing demand for biosensor design reliability for early stage recognition of infectious agents or contagious diseases and potential proteins, nanoscale manufacturing designs had developed effective nanodynamic sensing assays and compact wearable devices. Dynamic developments of biosensor technology are also vital to detect and monitor advanced diseases, such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), diabetes, cancers, liver diseases, cardiovascular diseases (CVDs), tuberculosis, and central nervous system (CNS) disorders. In particular, nanoscale biosensor designs have indispensable contribution to improvement of health concerns by early detection of disease, monitoring ecological and therapeutic agents, and maintaining high safety level in food and cosmetics. This review reports an overview of biosensor designs and their feasibility for early investigation, detection, and quantitative determination of many advanced diseases. Biosensor strategies are highlighted to demonstrate the influence of nanocompact and lightweight designs on accurate analyses and inexpensive sensing assays. To date, the effective and foremost developments in various nanodynamic designs associated with simple analytical facilities and procedures remain challenging. Given the wide evolution of biosensor market requirements and the growing demand in the creation of early stage and real-time monitoring assays, precise output signals, and easy-to-wear and self-regulating analyses of diseases, innovations in biosensor designs based on novel fabrication of nanostructured platforms with active surface functionalities would produce ​remarkable biosensor devices. This review offers evidence for researchers and inventors to focus on biosensor challenge and improve fabrication of nanobiosensors to revolutionize consumer and healthcare markets.

Novel Floating and Grounded Memory Interface Circuits for Constructing Mem-Elements and Their Applications

Memory elements (known as mem-elements) include memristor, memcapacitor and meminductor. They are considered the keys to developing the new generation of intelligent and neuromorphic devices. However, the complicated nano-scale manufacturing technique makes them difficult to produce, impeding the research and commercialization activities of mem-element devices. The emerging independent/universal emulators is considered one of the most promising candidates for mem-elements research. In this paper, for the completeness of circuit theory, the mathematical representations, classification, concept of unfolding with the extended formulation of three mem-elements are described, respectively. Then, a newly proposed floating and grounded memory interface circuits with wide frequency range are presented, together with the mathematical model and fingerprints. We also discuss the main affecting factors of frequency and demonstrate that the frequency of memristor is as high as 900kHz, and the highest frequency of memcapacitor also exceeds 500kHz. Finally, we explore a potential application based on the proposed interface circuit, i.e., a simple chaotic circuit. Also, the models, strange attractors, and Lyapunov exponents of three chaotic systems with mem-element are obtained, respectively. There is no doubt that the good agreement among theoretical analysis, simulation and experimental results verifies the practicability and flexibility of these interface circuits.

Examination of the influence of cutting conditions on nano-metric face milling using MD models

Machining is indispensable in the manufacturing sector for a wide variety of products. In the last years, the field of micro- and nano-scale manufacturing attracted a lot of interest, especially in high-end industries such as the biomedical and electronics industries. In order to improve the efficiency of these processes and understand the various underlying phenomena, it is important to develop relevant theoretical models. However, methods such as the Finite Element Method (FEM), which are well-established in the macro- or micro-scale level are not appropriate for creating models of nano-scale processes, as they treat the materials as continua. For that reason, the Molecular Dynamics (MD) method is usually used for simulations of nano-metric machining processes such as nano-milling. In the present study, a MD model of nano-milling is created and an investigation regarding the effect of cutting conditions such as feed rate and cutting speed on cutting forces, temperature and subsurface damage is conducted.

Digital Assembly of Colloidal Particles for Nanoscale Manufacturing.

From unravelling the most fundamental phenomena to enabling applications that impact our everyday lives, the nanoscale world holds great promise for science, technology and medicine. However, the extent of its practical realization would rely on manufacturing at the nanoscale. Among the various nanomanufacturing approaches being investigated, the bottom-up approach involving assembly of colloidal nanoparticles as building blocks is promising. Compared to a top-down lithographic approach, particle assembly exhibits advantages such as smaller feature size, finer control of chemical composition, less defects, lower material wastage, and higher scalability. The capability to assemble colloidal particles one by one or "digitally" has been heavily sought as it mimics the natural way of making matter and enables construction of nanomaterials with sophisticated architectures. This progress report provides an insight into the tools and techniques for digital assembly of particles, including their working mechanisms and demonstrated particle assemblies. Examples of nanomaterials and nanodevices are presented to demonstrate the strength of digital assembly in nanomanufacturing.

New lithography technique based on electrohydrodynamic printing platform

Abstract In the present work, we propose a new lithography technique combining UV (ultraviolet) exposure with electrohydrodynamic (EHD) printing. How to improve traditional photolithography is still a challenge due to its complex steps and expensive process. EHD printing is a very promising and potential technique for micro- and nano-scale electronic structures manufacture. The newly developed lithography technique enables a reduction of fabrication steps from six to two comparing with traditional photolithography. Based on the home-made EHD printing platform, linear photoresist structures were printed under different printing conditions to analyze the influence of printing parameters on the line width and printing resolution. In addition, we also discussed some phenomena and problems in the printing process, such as different combination of parameters to get different line widths, different printing modes and so on. According to our research, straight lines with line width of 9 μm can be fabricated, demonstrating the feasibility of the developed lithography technique based on EHD printing.

Experimental investigations on ultrashort laser ablation for micro and nanomachining of materials

With the advantage of ultrashort pulse width and ultrahigh peak power, subpicosecond lasers can provide extremely precise machining, and therefore has been widely applied in micro and nanoscale manufacturing. We present the results of the experimental parametric study on efficiency, accuracy and quality of subpicosecond laser micromachining of materials, that have a potential for application in innovative devices and technologies. The laser micromachining process was performed with a Yb:KYW subpicosecond laser and a Ti:S femtosecond laser. The study contains a comparison between the two methods, and results analysis using advanced metrology techniques, such as 3D microscopy.

Homogeneous and Localized Deformation in Poly(Methyl Methacrylate) Nanocutting

Nanoscale manufacturing imposes demands on prediction of cutting processes on small scales. Predictive modeling schemes based on the underlying physical mechanisms could potentially be more generally applicable in manufacturing. In this work, the experimental and numerical studies on polymethyl methacrylate (PMMA) nanocutting are reported. The cutting experiments were performed on an ultramicrotome instrumented with piezoelectric transducers to measure the cutting forces on cutting down to about 60 nm thickness. Using atomic force microscopy, the surface damage was identified as shear yield bands triggered by adiabatic heating. A suitable physical model including these observed phenomena made it possible to link the processing conditions with the onset of damage, i.e., the transition between a high-quality transparent surface and a damaged uneven surface. Finite element analysis was carried out to investigate the deformation modes of PMMA under different cutting conditions and to predict the formation of the undesired shear bands. From an engineering perspective, such an approach could be potentially useful in improving manufacturing control.

Computing properties of stable configurations of thermodynamic binding networks

The promise of chemical computation lies in controlling systems incompatible with traditional electronic micro-controllers, with applications in synthetic biology and nano-scale manufacturing. Computation is typically embedded in kinetics—the specific time evolution of a chemical system. However, if the desired output is not thermodynamically stable, basic physical chemistry dictates that thermodynamic forces will drive the system toward error throughout the computation. The thermodynamic binding network (TBN) model was introduced to formally study how the thermodynamic equilibrium can be made consistent with the desired computation, and it idealizes tradeoffs between configurational entropy and binding. Here we prove the computational hardness of natural questions about TBNs and develop a practical algorithm for verifying the correctness of constructions by translating the problem into propositional logic and solving the resulting formula. The TBN model together with automated verification tools will help inform strategies for error reduction in molecular computing, including the extensively studied models of strand displacement cascades and algorithmic tile assembly.

Design and comparison of new fault-tolerant majority gate based on quantum-dot cellular automata * * Project supported by the National Natural Science Foundation of China (No. 61271122).

Quantum-dot cellular automata (QCA) is increasingly valued by researchers because of its nanoscale size and very low power consumption. However, in the manufacture of nanoscale devices prone to various forms of defects, which will affect the subsequent circuits design. Therefore, fault-tolerant QCA architectures have become a new research direction. The purpose of this paper is to build a novel fault-tolerant three-input majority gate based on normal cells. Compared with the previous structures, the majority gate shows high fault tolerance under single-cell and double-cell omission defects. In order to examine the functionality of the proposed structure, some physical proofs under single cell missing defects are provided. Besides, two new fault-tolerant decoders are constructed based on the proposed majority gate. In order to fully demonstrate the performance of the proposed decoder, the previous decoders were thoroughly compared in terms of fault tolerance, area and delay. The result shows that the proposed design has a good fault tolerance characteristic, while the performance in other aspects is also quite good.

A Quantification of Jet Speed and Nanofiber Deposition Rate in Near-Field Electrospinning Through Novel Image Processing

Electrospinning, one of the most effective ways of producing nanofibers, has been applied in as many fields throughout its long history. Starting with far-field electrospinning (FFES) and advancing to the near-field, the application area has continued to expand, but lack of understanding of the exact jet speed and fiber deposition rate is a major obstacle to entry into precision micro- to nano-scale manufacturing. In this paper, we, for the first time, analyze and predict the jet velocity and deposition rate in near-field electrospinning (NFES) through novel image analysis process. Especially, analog image is converted into a digital image, and then, the area occupied by the deposited fiber is converted into a velocity, through which the accuracy of the proposed method is proved to be comparable to direct jet speed measurement. Finally, we verified the proposed method can be applied to various process conditions without performing delicate experiments. This research not only will broaden the understanding of jet speed and fiber deposition rate in NFES but also will be applicable to various areas including patterning of the sensor, a uniform arrangement of nanofibers, energy harvester, reinforcing of composite, and reproducing of artificial tissue.

Apochromatic singlets enabled by metasurface-augmented GRIN lenses

Chromatic aberrations are a primary limiting factor in thin, high-quality imaging systems. Recent advances in nanoscale manufacturing, however, have enabled the creation of metasurfaces: ultra-thin optical components with sub-wavelength features that can locally manipulate the wavefront phase. Meanwhile, there has been renewed interest in GRadient-INdex (GRIN) lenses due to the extended degrees of design freedom they offer. When combined, these two technologies can provide unparalleled imaging system performance while realizing drastic reductions in size, weight, and power. Through paraxial theory and full ray tracing we produce a lens singlet that can achieve three-color (apochromatic) correction by employing a metasurface-augmented GRIN. This apochromatic singlet has the potential for application in high-quality optical systems.