Microfabrication Research Articles

Determining the Dependence of Single Nitrogen-Vacancy Center Light Extraction in Diamond Nanostructures on Emitter Positions with Finite-Difference Time-Domain Simulations.

In this study, we obtained a diamond nanocone structure using the thermal annealing method, which was proposed in our previous work. Using finite-difference time-domain (FDTD) simulations, we demonstrate that the extraction efficiencies of nitrogen-vacancy (NV) center emitters in nanostructures are dependent on the geometries of the nanocone/nanopillar, emitter polarizations and axis depths. Our results show that nanocones and nanopillars have advantages in extraction from emitter dipoles with s- and p-polarizations, respectively. In our simulations, the best results of collection efficiency were achieved from the emitter in a nanocone with s-polarization (57.96%) and the emitter in a nanopillar with p-polarization (38.40%). Compared with the nanopillar, the photon extraction efficiency of the emitters in the nanocone is more sensitive to the depth and polarization angle. The coupling differences between emitters and the nanocone/nanopillar are explained by the evolution of photon propagation modes and the internal reflection effects in diamond nanostructures. Our results could have positive impacts on the design and fabrication of NV center-based micro- and nano-optics in the future.

Preparation and surface nanostructural characterization of multi-emitter sources based on superionic conductor CsAg4Br3-xI2+x (x=0.25)

Since the fabrication of micro-/nano-electronic devices is approaching nanoscales and demanding low energy, high dose ion beam processing with controlled area and dense patterns to meet the current semiconductor industry demands, continuous advancement is needed in terms of material design and ion beam techniques. In this perspective, development of new ion sources may provide advanced technologies useful in the manufacture of high-performance devices. Silver ion beams have salient features including simple generating process, nanoscale beam spot size and high intensity ion current. In this paper, we have developed a solid electrolyte multi emitter ion source (SEIS) with CsAg4Br3-xI2+x (x = 0.25) films deposited on silver tips. Ag+ ion emission is significantly enhanced with the added number of emitters and the ion current of 1.95 μA (with four emitter tips) has been obtained at 168 °C temperature and 20 kV accelerating voltage. The stability and cooling/heating curves of the multi-emitter ion beam are measured, and the interrelation between ion current intensity and mechanism of shape geometry of the emitter tips are discussed. Finally, both the solid electrolyte multi-tip emitters and the collector surfaces are analyzed, with an attempt to precisely control of formation of the nanoparticles (NPs) including their size and height through the control of the ion implantation parameters.

An Institutional Regulatory Analysis for Genetically Modified Products with special reference to Bt Mustard

Rules for the Manufacture, Use/Import/Export, and Storage of Hazardous Micro Organisms/Genetically Engineered Organisms or Cells, 1989 has laid down several guidelines to ensure environmental safety in the use of genetically modified organisms (GMOs) and to provide regulatory approvals for dealing with genetically engineered (GE) entities.A few committees have been constituted under the 1989 rules and the Recombinant DNA (rDNA) safety guidelines, 1990 at the institutional level, including Genetic Engineering Approval Committee (GEAC). The Paper intends to analyze policy initiatives in the direction of biotechnology regulation in India, especially after the petition was filed opposing the government's approval of field trials for GM crops. The petitioner has sought Supreme Court's intervention in the matter with a clear direction to the government for not pushing and going ahead with the approval of field trials of GM crops.

Pyrolyzed photoresist thin film: Effect of electron beam patterning on DC and THz conductivity

Pyrolyzed photoresist films (PPFs), which are formed via vacuum annealing of a photoresist without a catalyst, can be employed for fabrication of graphitic nanostructures by using conventional lithographic techniques. Such approach allows for reduction of technological steps required for fabrication of conductive micro- and nanoelectrodes for different applications. However, the operation frequency range of PPF electrodes is still unknown. Here, we report the results of the comparative study of PPF structures fabricated by electron beam lithography prior and after the annealing process with preference to the first approach. By performing the comparative measurements of PPF transport properties we found that both pre-and post-processed PPFs possess the same conductivities at dc-current and in the frequency range from 0.2 to 1.5 THz. Moreover, we achieved the sheet resistance of 150 nm thick PPFs as low as 570 Ω/sq, which is comparable to that of commercially available chemical vapour deposited (CVD) graphene. These findings open a path for a simple, reproducible and scalable fabrication of graphitic nanocircuits, nanoresonators and passive components suitable for applications in frequencies up to few terahertz.

Modeling and Simulation of a Massively Parallelized Multiphoton Polymerization 3D Microfabrication Process

While additive manufacturing based on multiphoton polymerization is currently considered to be a very promising technique for the fabrication of 3D micro‐ and nanostructures, long fabrication times are a major limitation of this approach. Parallelization of the fabrication process is an important technique to overcome this issue. The fabrication process is parallelized by imaging a 1920 × 1080 pixel spatial light modulator into an ultrasensitive triplet–triplet annihilation resist. However, proximity effects between close pixels generate uncontrolled polymerization and make the controlled fabrication of 3D structures difficult. This work models light propagation and chemical interactions in the system to predict fabricated structures with a view to precompensating plot data and improving 3D resolution by performing optical and chemical proximity correction. A simple model gives reasonable predictions of fabricated structures helping us fabricate fully 3D structures in parallel.

Achieving sustainability through the integration of lean, agile, and innovative systems: implications for Indian micro small medium enterprises (MSMEs)

Purpose The purpose of this study is to learn how the incorporation and use of leanness, agility and innovation in Indian manufacturing micro, small and medium enterprises (MSMEs) affect their bottom lines and how much these factors contribute to the MSMEs’ ability to meet their long-term sustainability goals. Design/methodology/approach The suggested model was subjected to data validation and additional empirical validation using a sample of 411 Indian manufacturing MSMEs. The analysis of construct measures is conducted through the utilization of confirmatory factor analysis, a statistical technique that is grounded in the theoretical framework of structural equation modeling (SEM). In addition, path model analysis was applied for the purpose to validate the assumptions that were included in the structural models. Findings Consistent with the proposed model, the findings of this study demonstrate that leanness, agility and innovation have a substantial favorable impact on the sustainability of a company’s performance. These findings may be helpful in gaining professionals, academics and policymakers to acknowledge the significance of leanness, agility and innovation in enhancing the long-term sustainability of MSMEs and enhancing the overall performance of a particular company. This research excluded the service industries-based research papers. Research limitations/implications Many research in the field of manufacturing industries that have adopted leanness, agility, innovativeness and sustainability as individual approaches or as a collective methodology of two or more were considered in the current study. This research excluded the service industries-based research papers. Practical implications This literature review has recognized and analyzed various dimensions and roles of leanness, agility, innovativeness and sustainability that are prevalent in manufacturing industries that include the positive and negative effects on the performance of the industries. The research enlightens the path and shows future directions for research to develop efficient, effective and sustainable manufacturing industries. Social implications By promoting the concept of focusing on the “human factor”, namely, stakeholder perspectives, the MSME sector is propagating a strategy that moves away from an excessive focus on technology and toward a more humane one. Through the application of the three key concepts of leanness, agility and innovation, this work aims to create a framework for measuring the sustainability performance of micro-, small- and medium-sized enterprises (MSMEs), with the ultimate goal of assisting the country in achieving the Sustainable Development Goals in the fields of industry, innovation and infrastructure by supporting environmentally friendly and resource-conserving businesses that give back to society and the natural environment. Originality/value The objective of this research is to assess the importance and effectiveness of integrating various approaches such as leanness, agility, innovativeness and sustainability within the framework of manufacturing micro, small, and medium enterprises (MSMEs). The authors hope that by going further into these concepts, they will be able to broaden their understanding and get a more comprehensive insight into the role that these concepts play and how they might be successfully used within this environment.

Is this time different? How Industry 4.0 affects firms’ labor productivity

Does Industry 4.0 technology adoption push firms’ labor productivity? We contribute to the literature debate—mainly focused on robotics and large firms—by analyzing adopters’ labor productivity returns when micro, small, and medium enterprises (MSME) are concerned. We employ original survey data on Italian MSMEs’ adoption investments related to a multiplicity of technologies and rely on a difference-in-differences estimation strategy. Results highlight that Industry 4.0 technology adoption leads to a 7% increase in labor productivity. However, this effect decreases over time and is highly heterogeneous with respect to the type, the number, and the variety of technologies adopted. We also identify potential channels explaining the labor productivity returns of technology adoption: cost-related efficiency, new knowledge creation, and greater integration/collaboration both within the firm and with suppliers.Plain English SummaryBecoming Industry 4.0 technology adopter boosts Italian manufacturing micro, small, and medium enterprises’ (MSME) labor productivity by more than 7% on average. This is the key finding of new research based on original survey data collected from a sample of MSMEs operating in “Made in Italy” industries. Specifically, the research suggests that brand-new adopters of Industry 4.0 technologies gain a labor productivity premium compared to their non-adopting counterparts that lasts for up to 2 years after the adoption occurred. However, the productivity returns of technology adoption show non-linearities with respect to both the number of new technologies adopted by the firm and the variety of “technology groups” (production, customization, and data processing technologies). Overall, these results point to the relevance of industrial policies promoting the adoption of Industry 4.0 technologies by MSMEs, and this seems to be particularly the case for all those countries where MSMEs make the bulk of the national industrial system.

Electrochemical Deposition of Micro- and Nanostructures of Any Shape

Meniscus-confined electrochemical deposition (MCED) is a promising method for the fabrication of micro- and nanostructures with high precision and resolution. The success of MCED depends on the optimization of several parameters, including duty cycle, voltage, frequency, electrolyte concentration, anode movement speed, anode shape, electrolyte circulation, and additives. Porosity, structure, hardness, yield strength, and composition are the critical factors that determine the quality of deposited structures. This article summarizes the effects of various factors on the outcome of the MCED process, which involves controlled deposition of voxels to create an object. Optimizing these parameters can lead to high-quality structures with good resolution and size. The article points out the relationship between these factors and the resulting properties of the deposited object, which may be useful for future research in this area. It also points to different types of approaches for the preparation of these structures through electrochemical additive manufacturing (ECAM) and its detailed mechanism.

The effects of job crafting and engagement in improving the performance of micro, small and medium enterprises

Purpose: Previous studies have found mixed results regarding the effect of job crafting (JC) on employee engagement (EE) and employee performance (EP). JC was also influenced by the type of work and tenure. Therefore, the present study examined the relationship between JC and EE in increasing in-role (IRP) and extra-role performance (ERP). Additionally, it analyses JC on manufacturing and service micro, small and medium enterprise (MSME) and differences in tenure.Design/methodology/approach: The study was conducted using 1032 employees who work in MSME in Indonesia, especially in Yogyakarta. Validity and reliability tests were carried out for the questionnaire, and Chi-square was used to test the JC difference for the type of work, analysis of variance was used to test the JC difference on tenure, and structural equation modeling (SEM) to analyze the relationship model.Findings/results: The results of SEM with a two-step approach found that EE mediated the effect of JC on performance. Depending on the type of work performed, the challenges of manufacturing companies differed from those of service companies. The tenure also distinguished the JC that was carried out.Practical implications: Job crafting is a phenomenon of employee creativity that is important for achieving a good fit in the workplace and increase EE and EP. The human resources department needs to optimize this concept by regulating the procedures for conducting JC.Originality/value: The results found that the effect of JC was only on IRP and was different, negative, positive and insignificant. Furthermore, JC is proven not to affect ERP.

A novel hot embossing process for producing high-quality glass micro-pillar arrays

Hot embossing is an efficient technology for the fabrication of glass micro- and nanostructures. However, the long cycle time, high energy consumption, and high nitrogen emissions in traditional hot embossing approach hinders sustainable production of glass micro-optics. Therefore, this paper proposes a novel two-stage gravity-assisted hot embossing process that enables the fabrication of high-quality glass micro-pillar arrays in a rapid, green manner. In this approach, the two-stage gravity loading unit provides accurate force on glass preform through a simple control system, and the tailor-made heating module based on Si3N4 ceramic heaters requires an energy consumption of just 700 kJ per molding cycle. As a result, the proposed approach is featured by low energy consumption and high manufacturing efficiency. In this study, the effects of the embossing temperature, force, and time on the replication accuracy of a K9 glass micro-pillar array were investigated through a series of hot embossing experiments. Afterward, the form accuracy, uniformity of microstructures, and warpage of glass replicas under the optimal process parameters were evaluated separately. Finally, repeated hot embossing experiments were conducted to demonstrate the reproducibility of the hot embossing process. The experimental results show that embossing temperature had the most significant effect on the replication accuracy of glass micro-pillars. By optimizing the process parameters, the embossed glass micro-pillars could achieve transfer ratios of 99.00% and 95.14% in height and diameter, respectively. Moreover, the surface roughness of glass micro-pillars was less than 5 nm, and the warpage amplitude of glass replicas in a 3.9 × 3.9 mm area was smaller than 1 μm. The small discrepancy in geometric features of glass replica in the repeated trails reflects the satisfactory reproducibility of this hot embossing process on the micro and nano scales. The results indicate the strong industrialization potential of the proposed two-stage gravity-assisted hot embossing machine and hot embossing process for fabricating high-quality glass microstructures more cleanly and sustainably.

Modular Direct Laser Writing setup for high precision nanostructuring

Abstract The increasing demand for micro- and nanofabrication and in parallel the increasing requirements on feature size and resolution is leading to an enormous growth in the field of multi-photon three-dimensional fabrication. To enable new and diverse investigations in this field and to enable high precision for nanofabrication on large areas, a high precision positioning system is combined with an ultra-short pulse laser system. The aim is a modular setup with constant adherence to the Abbe-comparator principle in order to achieve systematic improvements in the area of Direct Laser Writing. For a high-quality identification of the microstructures a measurement tool based on atomic force microscopy is used. To enable the fabrication of continuous micro- and nanostructures on large area, an extremely high positioning precision is used, where no further stitching methods are necessary. Therefore as base of the Direct Laser Writing system the nanopositioning and nanomeasuring machine (NMM-1) is used, which was developed at Technische Universität Ilmenau together with SIOS Meßtechnik GmbH, with a positioning volume of 25 mm × 25 mm × 5 mm and a positioning resolution in the sub-nanometer range. First investigations already confirmed that microfabrication with a Femtosecond Laser and the NMM-1 could be realized and showed the possibility of further developments in the field of Direct Laser Writing. Now the modular structure as a research platform is designed in such a way that the various extensions and measurement setups for large-scale investigations can always be implemented in a metrologically traceable manner. The presented work shows the development of a modular functional setup of an exposure system and NMM-1, which enables micro- and nanofabrication and an improvement in the structure size over large areas.

The high-throughput atomization of polymer solutions for fiber synthesis in a single step aided with corona ionizers

Polymer microfibers are ubiquitous structures across virtually all technological fields. Their applications include, for instance, filter media, tissue regeneration, wound healing and dressing, and reinforcement materials. The most effective methods for fabrication of fibrous micro and nanomaterials rely on electric fields to spin a liquid jet into an ultrafine thread that rapidly dries up forming a fiber. Continuous spinning and collection leads to formation of fiber mats. Here we report a robust yet simple approach for the massive production of liquid threads, which upon acquiring electrical charges in-flight are collected downstream in the form of fibers. The entire process takes place on-line in a single step. The liquid threads are produced through the fragmentation of a polymer solution bulk due to a turbulent interaction of a gas–liquid interface in the interior of an engineered device, a so-called Flow Blurring atomizer. The particularity of this approach consists precisely in such vigorous interaction, at the micrometer scale, which triggers a bubbly motion in the interior of the device, that is a “micro-mixing”. Subsequently, the threads are passed through ionized air currents, at ambient conditions, and then stretched to sub-micrometer dimensions by electric fields. Polyvinylpyrrolidone (PVP) as well as carbon nanotubes (CNTs) or graphene oxide sheets (GOSs)-containing PVP fibers, with diameters in the range 100–900 nm, were synthesized via this approach. In the cases studied herein the method was operated at liquid flow rates (i.e. production rates) of 0.2 mL/min but it could be readily increased up to a few tens of mL/min. The method requires further improvement and optimization, nevertheless it is a promising alternative for mass production of polymer fibers.

Global analysis of kinetics reveals the role of secondary nucleation in recombinant spider silk self-assembly.

Recombinant spider silk proteins can be prepared in scalable fermentation processes and have been proven as sources of biomaterials for biomedical and technical applications. Nanofibrils, formed through the self-assembly of these proteins, possess unique structural and mechanical properties, serving as fundamental building blocks for the fabrication of micro- and nanostructured scaffolds. Despite significant progress in utilizing nanofibrils-based morphologies of recombinant spider silk proteins, a comprehensive understanding of the molecular mechanisms of nanofibrils self-assembly remains a challenge. Here, a detailed kinetic study of nanofibril formation from a recombinant spider silk protein eADF4(C16) in dependence on the protein concentration, seeding and temperature is provided. For the global fitting of kinetic data obtained during the fibril formation, we utilized the online platform AmyloFit. Evaluation of the data revealed that the self-assembly mechanism of recombinant spider silk is dominated by secondary nucleation. Thermodynamic analyses show that both primary and secondary nucleations, as well as the elongation step of the eADF4(C16), are endothermic processes. This article is protected by copyright. All rights reserved.

Self-Propelled Micro-/Nanomotors of ZnO Nanoshuttles Induced by Surface Defects

To accomplish various complex tasks in the microworld, micro-/nanomotors (MNMs) with diverse swimming characteristics have attracted more and more attention. In this work, ZnO nanoshuttles were synthesized by a simple hydrothermal method. In addition, MNMs based on ZnO nanoshuttles have been designed, exhibiting self-propelled swimming characteristics with three motion modes of shake, rotation, and translation in water. It is revealed that the asymmetrically distributed defects on the surface of ZnO nanoshuttles are responsible for the swimming modes. The unique shuttle-like structure helps to reduce the drag in a low Reynolds number environment and endows the self-propelled ZnO nanoshuttle motor with a relatively high swimming velocity (5.16 μm/s). In addition, to demonstrate the versatility and openness of ZnO nanoshuttle MNMs, ZnO/Co magnetic MNMs and ZnO/TiO2 Janus MNMs were prepared by simple Co doping and TiO2 coating, respectively. This study reveals the possible role of surface defects in regulating the motion behavior of ZnO-based MNMs and also provides a feasible low-cost method for the large-scale fabrication of self-asymmetric fuel-free micro-/nanomotors.

Real‐Time 3D Visualization of the Formation of Micrograting Structures Upon Direct Laser Interference Patterning of Ge

AbstractDirect Laser Interference Patterning (DLIP) is a versatile technique that enables the fabrication of periodic micro‐ to nanometric scale structures over large areas in a variety of materials. The periodically modulated excitation pattern can be exploited to trigger a range of complex processes, including heating, melting, ablation, and matter reorganization.In this work, a novel strategy is developed to combine deep‐ultraviolet (UV) DLIP (λ = 193 nm, τ = 23 ns) and real‐time optical reflectivity and diffraction techniques to unravel the formation dynamics of grating structures with periods down to Λ = 740 nm. Applied to crystalline Ge wafers, single‐pulse topography modulation profiles with amplitudes up to 85 nm can be imprinted. Moreover, the dynamics of the melting and solidification processes, as well as the surface topography deformation, can be followed in real‐time. Combined with a model, changes in topography over time with ns resolution can be obtained. The results unambiguously reveal that the formation process of the 3D structures can only be understood when taking both Marangoni convection and thermocapillary waves into account. The technique presented here has the potential to unravel the formation dynamics of a wide range of periodic structures in other materials.

Electrospinning of Ternary Aqueous Solutions of Polyvinyl Alcohol, Chitosan and Salicylic Acid

The electrospinning technique is being widely used in the fabrication of micro and nanofibers, with a myriad of biomedical applications such as drug inoculation, tissue regeneration and scaffold production. In the present article, nanofibers based on polyvinyl alcohol (PVA), chitosan (C) and salicylic acid (SA) were developed experimentally. Solutions at 18% w/w of PVA and 3% w/w of C and SA were prepared using always distilled water as solvent. Solution with C and SA (labelled as CSA solution) had the same amount of both substances in it. Then, mixtures at 100/0, 98/2, 96/4, 93/7 and 90/10 in PVA/CSA weight ratio were prepared. The rheological behavior of the solutions was evaluated and they were subsequently electrospun. The samples were characterized by scanning electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy in attenuated total reflection mode.

Transient viscoelastic heating characteristics of polyethene under high frequency hammering during ultrasonic plasticizing

As a polymer molding technology developed in recent years, ultrasonic plasticizing micro-injection molding has great advantages in the manufacture of micro–nano parts by virtue of low energy consumption, less material waste and reduced filling resistance. However, the process and mechanism of transient viscoelastic heating for polymers under ultrasonic high-frequency hammering are unclear. The innovation of this research is that a combination of experiment and MD (molecular dynamics) simulation was adopted to study the transient viscoelastic thermal effect and microscopic behavior of polymers with different process parameters. To be more specific, a simplified heat generation model was first established and high-speed infrared thermal imaging equipment was applied to collect temperature data. Then, a single factor experiment was conducted to investigate the heat generation of a polymer rod with various process parameters (plasticizing pressure, ultrasonic amplitude and ultrasonic frequency). Finally, the thermal behavior during the experiment was supplemented and explained by MD simulation. The results showed that changes in ultrasonic process parameters produce different forms of heat generation, and there are three forms of heat generation, which are dominant heat generation at the ultrasonic sonotrode head end, dominant heat generation at the plunger end, and simultaneous heat generation at the ultrasonic sonotrode head end and the plunger end.

Additive manufacturing and post-processing of superelastic NiTi micro struts as building blocks for cardiovascular stents

Additive manufacturing and post-processing of superelastic NiTi micro struts as building blocks for cardiovascular stents

The Influence of Internal Locus of Control and Entrepreneurial Skills Training on the Growth of Micro and Small Enterprises in Bomet County, Kenya

There is an ongoing argument that internal locus of control of business owners or managers can be related to the growth and survival of the business. The internal locus of control might be affecting the growth of enterprises as internal locus of control of an entrepreneur differs from the characteristics of a non-entrepreneur Some researchers have tried to define success in terms of turnover, sustainability, and growth. Some researchers have observed that entrepreneurial traits are indicators of success. The general research issue that has to be addressed in this study is the fact that, in addition to financing and markets, there are additional variables impacting the high mortality rate and stunted growth of micro and small firms in Kenya, particularly in Bomet County. So, this study will look at the connection between the development of micro and small businesses in Bomet County and internal locus of control. In this study, the moderating impact of training in entrepreneurial skills will be examined. The target population was micro and small enterprises in Bomet County which were 14,574 in number in 2016. The unit of observation was the managers and owners of these enterprises. The unit of analysis in the micro and small enterprises in Bomet County and their growth over the past five years. The study used a stratified sampling technique to pick the respondents from the manufacturing, trade, and services strata of micro and small enterprises. The sample size was 384 micro and small enterprises. Data was collected using a questionnaire. Data collection was done by administering the instrument to the owners or managers of the enterprises. The data was processed using computer software. The association between the internal locus of control of entrepreneurs and the expansion of businesses was established using a multiple regression model. The main conclusions were that the expansion of businesses in Kenya's Bomet County is influenced by internal locus of control. The study's main advice is that the key participants in the firms should train to develop the traits of owners and managers. This study also suggests that not everyone can succeed as an entrepreneur. Resources and a methodology should be available to find future entrepreneurs. The necessary resources cannot be accessed before identification.

Ion-Induced Lateral Damage in the Focused Ion Beam Patterning of Topological Insulator Bi2Se3 Thin Films

Focused Ion Beam patterning has become a widely applied technique in the last few decades in the micro- and nanofabrication of quantum materials, representing an important advantage in terms of resolution and versatility. However, ion irradiation can trigger undesired effects on the target material, most of them related to the damage created by the impinging ions that can severely affect the crystallinity of the sample, compromising the application of Focused Ion Beam to the fabrication of micro- and nanosized systems. We focus here on the case of Bi2Se3, a topological material whose unique properties rely on its crystallinity. In order to study the effects of ion irradiation on the structure of Bi2Se3, we irradiated with Ga+ ions the full width of Hall-bar devices made from thin films of this material, with the purpose of inducing changes in the electrical resistance and characterizing the damage created during the process. The results indicate that a relatively high ion dose is necessary to introduce significant changes in the conduction. This ion dose creates medium-range lateral damage in the structure, manifested through the formation of an amorphous region that can extend laterally up to few hundreds of nanometers beyond the irradiated area. This amorphous material is no longer expected to behave as intrinsic Bi2Se3, indicating a spatial limitation for the devices fabricated through this technique.