Fabrication Process Research Articles

Multi-project wafer runs for electronic graphene devices in the European 2D-Experimental Pilot Line project

Abstract The commercialization of electronic devices based on graphene has not yet been successful, even 20 years after its first isolation. To this end, the European Commission is supporting research toward establishing a European experimental pilot line for electronic and optoelectronic devices based on graphene and related two-dimensional (2D) materials, namely the Experimental Pilot Line (2D-EPL) project. Here, we report the results obtained during the first and third multi-project wafer (MPW) runs completed at the end of 2022 (MPW run 1) and 2023 (MPW run 3) as an outcome of the 2D-EPL. Test devices were measured across the wafers to assess the device quality and variability before delivering the fabricated dies to the customers. Raman spectroscopy confirmed minimal structural changes in the graphene caused by the fabrication process, while electrical measurements of two different device types verified the device specifications defined in the process design kit.

Effect of Carbon Nanomaterials Incorporated Polymeric Membrane Separators for Energy Storage Devices.

The rapid expansion of the global population and technological advancements have heightened the need for efficient energy conversion and electrochemical energy storage. Electrochemical energy systems like batteries and supercapacitors have seen notable development to meet this demand. However, conventional polymeric membrane separators in these systems face challenges due to limited porosity and poor mechanical and thermal properties, reducing overall electrochemical performance. Researchers have incorporated nanoparticles into the polymer matrix to address these limitations and enhance separator properties. Carbon-based nanomaterials, in particular, have gained prominence due to their unique features, such as surface-dependent characteristics, size, porosity, morphology, and electrical conductivity. These properties make carbon-based nanomaterials advantageous in improving energy storage compared to conventional materials. Advanced carbon-doped polymeric membrane separators have emerged as a potential solution to the issues faced by conventional separators. Adding carbon nanoparticles, such as graphene-based materials and carbon nanotubes to the polymeric separators of batteries and supercapacitors has helped researchers solve problems and improve the electrochemical performance. This review article provides a state-of-the-art overview of carbon-doped polymeric membrane separators, their properties, fabrication processes, and performance in lithium batteries, as well as supercapacitors. It emphasizes advantages of these novel separator materials and suggests future research directions in this field.

Utilizing focused field as a probe for shape determination of subwavelength structures via coherent Fourier scatterometry

Nanopillars are widely used for various applications and require accurate shape characterization to enhance their performance and optimize fabrication processes. In this paper, we employ coherent Fourier scatterometry (CFS) combined with rigorous three-dimensional finite-difference time-domain simulations to accurately determine the shapes of nanopillars with various geometries, including cylindrical, triangular, square, and rectangular shapes. The nanopillars considered here have lateral dimensions (a) ranging from 100 to 1000 nm. Our methodology utilizes the preferential excitation of the nanostructures by a tightly focused beam and leverages their inherent symmetry to capture far-field signatures that vary periodically with rotation. This approach allows us to distinguish between different nanopillar shapes based on these rotational signatures. Our results demonstrate that the CFS method can reliably characterize nanopillars with lateral dimensions a≥300 nm, surpassing the conventional diffraction limit of 351 nm. However, the method reaches its fundamental limits for a≤200 nm, as also confirmed by simulations, where we approach the dipole approximation regime (a≪λ). This constraint is not observed for rectangular nanopillars, owing to their constant breadth (b=1000 nm), which prevents such a regime. Furthermore, our method successfully differentiates nanopillars transitioning from rectangular to square shapes. We also explored the method’s limitations concerning nanostructure height (h), finding that triangular and square nanopillars could be characterized accurately for h≥50 nm and h≥150 nm, respectively. Furthermore, the method remains robust against shape distortions such as edge roundness. The method is primarily effective in determining the lateral (top-down) shape of nanopillars, it does not resolve longitudinal features. The ability to accurately characterize nanostructure shapes has significant implications in fields such as photonics and biosensing, where geometry critically influences device performance. Published by the American Physical Society 2025

Preparation of copper/binder composites and fused filament fabrication process

Purpose The purpose of this study is to assess the effects of fused filament fabrication (FFF) printing parameters on the surface quality and dimensional accuracy of FFF-fabricated copper green parts using the appropriate filaments. The orthogonal experiments were implemented and the errors in length, width and height were measured and analyzed. The results of range analysis and variance analysis indicated the orders of effect factors. Dissolvent debinding combined with thermal debinding was adopted to remove the binders inside the green part by calculating debinding rate. The influence mechanism of sintering temperatures on the microstructure and shrinkage was elaborated. Design/methodology/approach The extrusion-based FFF in manufacturing copper parts can overcome shortcomings for high reflectivity and heat dissipation in laser powder bed fusion process at cost-saving and materials saving. This study makes an attempt to prepare copper/binder composite filaments through mixing, extrusion and flowability evaluation. Findings The results showed that the suitable composite filaments applied for FFF should balance rigidity and plasticity. The combination of printing speed and heating temperature impacts on the surface quality significantly, and the major factor in determining the dimensional accuracy is layer thickness. Two-stage debinding procedure was beneficial for binder removal and sintering process. The higher sintering temperature results in less voids, sizes shrinkage and densified microstructure, which is attributed to the occurrence of sintering neck among the fused copper powders. Originality/value The self-prepared copper/binder composite filaments were successfully manufactured using the FFF process. This study provides unique approach and print guidance for fabricating complex structures of pure copper components.

Simulation Design of an Electron Gun for Microchannel Plate Scrubbing

The microchannel plate (MCP) is susceptible to the adsorption of substantial amounts of gas during its fabrication process. To mitigate this, a uniform electron source is essential for effective electron scrubbing and gas removal. Thermionic emission, a method of electron generation, can be employed to create the electron source. In this study, a flat spiral filament was designed and simulated using the CST Studio Suite electron simulation software to assess the cleaning performance of the electron gun. The impact of variations in electron gun parameters on the uniformity of the electron beam and current density was systematically analysed. The simulation results show that, with filament, grid, focusing sleeve, and anode voltages set to 200 V, 500 V, 250 V, and 300 V, respectively, a uniform electron beam with a diameter exceeding 30 mm can be achieved. In order to obtain the current density (5~50 nA/mm2) required for the MCP, the temperature of the filament should be 1800–2000 K through theoretical calculation. These findings offer valuable insights for designing a more efficient electron gun for MCP scrubbing.

Protein-based microlasers: continuous transition from whispering gallery mode to random lasing

Abstract Whispering gallery mode (WGM) and random biolasers are important for bio-integration and biosensing applications due to their biocompatibility. However, these two laser types typically require different fabrication techniques, and limited research has explored transitioning between them using the same fabrication process. In this work, we present a comprehensive investigation into the transition from WGM to random lasing in protein-based microsphere lasers. Through a dehydration method, we can fabricate dye-doped protein microspheres with diameters ranging from 20 to 150 µm. By varying the polystyrene (PS) particle concentration within these microspheres, we observed a continuous transition from WGM to random lasing under optical pumping, driven by enhanced light scattering as PS concentration increased. Key lasing parameters, including the lasing spectrum and lasing threshold versus laser size and PS concentration, were analyzed and compared. The results indicate that microsphere random lasers (RLs) exhibit shorter lasing wavelengths. Particularly, a 63 µm WGM laser has a central lasing wavelength at 630 nm, while a RL of similar size shows a peak wavelength at 590 nm, a 40 nm blue shift. The lasing threshold increases with smaller laser size and higher PS concentration, with WGM lasers requiring several µJ mm−2, potentially ten times lower than RLs. Our work opens the possibility of designing flexible, wavelength-tunable biological microlasers. Moreover, it provides an understanding of the distinct characteristics of WGM and random lasing, making a meaningful contribution to laser research.

Experimental and GEANT4 simulated FEPE of NaI(Tl) detector for linear sources

The current study investigated the geometry, design and solid angle impacts on full energy peak efficiency (FEPE) of NaI(Tl) detectors for a line source. A line source is fabricated using99mTc solution filled in a borosilicate glass tube of inner diameter 3 mm, tube wall thickness 2.5 mm and length 12.7 cm. The FEPE is measured for the fabricated linear source using 2″×2″ NaI(Tl) cylindrical detector at various source-detector distances. The experimental setup is simulated in GEANT4 and the computed FEPE values are compared with experimental values. The absolute error of 5% is observed between computed and measured FEPE values. Utilizing the advantages of MC simulations, the impact of numerous source parameters such as source length, diameter, source-detector distance, glass tube thickness and lead shield effects on FEPE are investigated to optimize the fabrication process of linear sources. A case study for current investigation has been analyzed by considering absolute FEPE of the NaI(Tl) system for a syringe filled with radioactive solution. This study provides an insight for the fabrication of standard linear sources by analyzing different source parameters and hence, may serve as a guideline to prepare standard linear sources for the calibration of radiation detectors.

Analysis of aluminium-sic hybrid composite based on Banana stem fibres

Fibre composites are emerging as a prominent player in curbing materials need along with the solving environmental degradation by using waste material as the as the substrate in composite. Because of their potential to improve material qualities, aluminium-based composites that include natural fibres and reinforcing agents have attracted a lot of attention. The goal of this research is to create a new aluminium composite by combining silicon carbide (SiC) particles with banana stem fibres. Examining how these additions affect the final composite's mechanical, thermal, and structural characteristics is the main goal. Banana stem fibres and SiC particles were first prepared as part of the fabrication process, and then they were cast into an aluminium matrix. When compared to traditional aluminium, the composite's strength and stiffness were significantly improved by subsequent characterisation using mechanical testing and microscopy techniques. The noted alterations in the material's microstructure and characteristics offer important new information on the possible uses of these composite in various industrial applications. This study opens the door for environmentally friendly and high-performing materials by highlighting the potential of using SiC particles and banana stem fibres as reinforcing agents in aluminium-based composites.

Highly transparent and semi-transparent perovskites and their applications

Perovskite has recently garnered significant attention as a promising semiconductor for optoelectronic applications and particularly for solar cells. In various applications, solar cells must be semi-transparent or even nearly fully transparent. Perovskite solar cells emerge as strong contenders to meet this requirement, owing to their remarkable versatility that allows for high transparency. Consequently, numerous studies on semi-transparent perovskite have been presented in recent years, demonstrating significant advancements in their properties. This review aims to explore color-neutral highly transparent and semi-transparent perovskite solar cells, encompassing their synthetic routes, challenges associated with their fabrication process, and potential solutions. The incorporation of potential additives or two-dimensional perovskites to enhance the properties of semi-transparent perovskite solar cells is also discussed. Finally, we will delve into some promising applications of semi-transparent perovskite solar cells and other applications that have been successfully studied.

Electrochemical Technology for the Detection of Tau Proteins as a Biomarker of Alzheimer’s Disease in Blood

Alzheimer’s disease (AD) is a prevalent neurodegenerative disorder and a significant cause of dementia in elderly individuals, with a growing prevalence in our aging population. Extracellular amyloid-β peptides (Aβ), intracellular tau proteins, and their phosphorylated forms have gained prominence as critical biomarkers for early and precise diagnosis of AD, correlating with disease progression and response to therapy. The high costs and invasiveness of conventional diagnostic methods, such as positron emission tomography (PET) and magnetic resonance imaging (MRI), limit their suitability for large-scale or routine screening. However, electrochemical (EC) analysis methods have made significant progress in disease detection due to their high sensitivity, excellent specificity, portability, and cost-effectiveness. This article reviews the progress in EC biosensing technologies, focusing on the detection of tau protein biomarkers in the blood (a low-invasive, accessible diagnostic medium). The article then discusses various EC sensing platforms, including their fabrication processes, limit of detection (LOD), sensitivity, and clinical potential to show the role of these sensors as transformers changing the face of AD diagnostics.

Nanoscale Silicon Fingerprints for Counterfeit Prevention in Microchips.

The increasing vulnerability of microchips to counterfeiting poses a significant threat to nations, companies, and the general public. Creating a unique "fingerprint" on each chip using intrinsic manufacturing variations can significantly prevent the number of fraudulent chips. Since Si-based semiconductor fabrication processes are now flawless down to a few nanometers, finding a high-entropy source at the nanoscale has become challenging. Inspired by the concept of physical unclonable function, this work reports the CMOS-compatible and lithography-free fabrication of unique nanostructured silicon "fingerprints." Nanostructuring is achieved via low-temperature dewetting and metal-assisted chemical etching, which produces a high level of entropy and unique silicon-based nanoscale fingerprints with linewidths tunable from ≈8 to 140nm, commensurate with the dimensions of mainstream microfabrication processes. These Si nanofingerprints are highly reliable for chip authentication and against reverse engineering, providing a large encoding capacity of up to 216384/µm2. For practical applications, detection of fingerprints protected with a polymer coating is demonstrated using back-scattered electron imaging.

Enhancement of tribological properties by fabricating gradient structure and MoS2 coating on the surface of 06Cr19Ni9 stainless steel

Abstract Stainless steel is extensively used in civil engineering and mechanical industries due to its superior corrosion resistance and mechanical performance. Nevertheless, its surface is prone to wear, which can compromise component functionality and introduce safety concerns. The present study developed a composite structure consisting of a gradient microstructure layer combined with a pure MoS2 coating on the surface of 06Cr19Ni9 stainless steel. The fabrication process involved ultrasonic shot peening using α-Al2O3 particles, followed by thermal spraying. Fretting friction and wear using the ball-on-disc method demonstrated a notable improvement in tribological performance. The composite structure achieved a remarkably low friction coefficient of 0.16 under a normal load of 15 N representing a 74.19% reduction compared to a mechanically polished sample. However, when subjected to a higher normal load of 50 N, the friction coefficient increased significantly. Despite a relatively higher wear rate, the composite structure effectively safeguarded the metal matrix from substantial wear during testing. The enhanced tribological properties were primarily attributed to the synergistic interaction between the gradient microstructure layer and the MoS2 coating. These findings underscore the potential of this composite structure to significantly improve the wear resistance and extend the operational life of 06Cr19Ni9 stainless steel.

One-step Centimeter-Scale Growth of Sub-100-nm Perovskite Single-Crystal Arrays in Ambient Air for Color Painting.

Halide perovskite single crystals have demonstrated enormous potential for next-generation integrated optoelectronic devices. However, there is a lack of a facile method to realize the controllable growth of large-scale, high-quality, and high-resolution perovskite single crystal arrays on diverse types of substrates, which hinders their application in practical scenarios. Here, a one-step wettability-guided blade coating approach is reported for the rapid in situ crystallization of large-scale, multicolor, and sub-100 nm perovskite single-crystal arrays in the ambient environment. By this strategy, the physical dimensions of perovskite single crystals can be precisely regulated from 90 to 260 nm, with a size variation coefficient < 10% and an area of over 900 mm2. All three typicalhalogen perovskites for multi-color luminescence, CsPbX3 (X = Cl, Br, I) and their mixtures (Cl/Br or Br/I systems), are appliable to this fabrication process through the demonstration of complex RGB patterns with remarkable photoluminescence properties. Moreover, various rigid substrates such as silicon oxide (SiO2), silicon (Si), and glass can also be used to construct the wettability-constrast templates where perovskite crystal nucleate and grow. After that, the perovskite single-crystal arrays or complex patterns can be transferred onto flexible substrates, for instance, COC. This method combines convenient solution processing with conventional photolithography to prepare the high-resolution, large-area, and superior-quality perovskite single crystal arrays in a high-throughput manner, showing great potential in the integration of perovskite nano-optoelectronic devices and chips.

Development and Experiment of Superconducting Eddy Current Braking Prototype Device

An experimental superconducting eddy current braking prototype was designed, constructed and thoroughly evaluated. The components of the apparatus were accurately described, and heat leakage was calculated. The results showed that the heat leakage was 0.53 W at 5 K and 19.2 W at 40 K. The selected cryogenic system met the operational requirements of the apparatus. The fabrication process was outlined, and the apparatus was tested with the integrated cryogenic system. The device successfully cooled to the target temperature. The circular coil, carrying a current of 180 A, generated a braking force of 0.7 kN at a speed of 400 km/h, while the racetrack coil, at 50 A, produced 0.15 kN at the same speed. The experimental results were consistent with the analysis, demonstrating the successful operation of the prototype throughout the testing phase.

Design and Implementation of Dummy fill for Chemical-Mechanical Polishing in Superconducting Single Flux Quantum Circuit Fabrication Process

Design and Implementation of Dummy fill for Chemical-Mechanical Polishing in Superconducting Single Flux Quantum Circuit Fabrication Process

Biocompatible Natural Polymers and Cutting-Edge Fabrication Techniques in the Development of Next-Generation Oral Thin Films for Enhanced Drug Delivery Systems.

Oral thin films are changing the way drugs are delivered, making drug administration more convenient and patient-friendly. This review delves into the fascinating possibilities of natural polymers in thin film design. We consider the benefits of biocompatible polymers produced from chitosan, gelatin, and pullulan. Their intrinsic biodegradability and safety make them excellent for use with a wide range of patients. Additionally, the research investigates novel strategies for creating these distinctive drug delivery systems. We look beyond standard solvent casting techniques, hot melt extrusion methods, rolling methods, etc. These technologies provide exact control over film qualities, allowing for tailored medication delivery and increased patient compliance. This review seeks to bridge the gap between natural polymers and cutting-edge fabrication processes. By investigating this combination, we pave the road for the development of next-generation oral thin films that are more efficacious, patient-acceptable, and environmentally-friendly.

Analysis of laser peeling fabrication processes and mechanisms of flexible coils for magnetostrictive nanogenerators

Analysis of laser peeling fabrication processes and mechanisms of flexible coils for magnetostrictive nanogenerators

Fabrication and Simulation of Optical Shaping Diffuser to Control Light Patterns

This study utilizes a 532 nm picosecond laser micromachining technique on Schott-B270 glass to fabricate micro-lens array (MLA) with optimized curvature and minimal surface roughness, aimed at achieving an optical shaping diffuser. The research demonstrates a two-step fabrication process that combines picosecond laser processing with wet etching, significantly enhancing optical diffusion. Square-shaped micro-lenses with diffusion angles ranging from 29° to 62° were successfully created, along with hexagonal and rectangular shapes. Optical simulations using LightTools, which employed built-in Bezier curves to design micro-lens parameters, analyzed the impact of micro-lens arrangements on light patterns. The simulations indicated that varying the spacing and overlap ratio of the micro-lenses influenced light intensity distribution, achieving uniform light patterns with intensity variations of less than 10%. Experimental validation through optical measurements confirmed that the fabricated MLA produced well-defined light patterns, demonstrating their effectiveness for various optical applications. This work contributes to advancing the understanding of micro-lens fabrication techniques and their applications in enhancing light distribution.

Rapid Dye Loading Techniques in Dye‐Sensitized Solar Cells

AbstractDye‐sensitized solar cells (DSSCs) greatly impacted researchers because of their inexpensive materials (organic/inorganic‐based molecules) and relatively simple fabrication process. The fabrication of DSSCs possesses donor‐acceptor type light‐harvesting materials and simple manufacturing techniques; the technology is the most environmentally friendly. In the process of preparing photoanode, adsorption of dye on the TiO2 is one of the crucial and time‐consuming processes. The conventional method of dye adsorption is carried out by dipping the FTO/TiO2 electrodes in dye solution for 12 to 48 h. In the DSSCs literature, very few techniques were explored to reduce the dye loading time. This review focuses on various dye loading methods, such as electrical adsorption, spray coating, microwave‐assisted ultrasonication, functionalized carboxylate deposition, solution dropping, and electrosorption, and so on. and their consequences in influencing the power conversion efficiency of DSSCs. Dipping and evaporation, solution dropping method, and gas bubbling soaking are inexpensive methods for dye loading. However, the electrochemical methods provide enhanced dye loading within an optimum duration resulting in the improvement of PCE as compared to rest of the methods.

Advances in Scaffolds and Additives for Infection Control in Autologous Chondrocyte Transplantation.

Cartilage tissue engineering (CTE) has revolutionized the field of regenerative medicine, offering significant advancements in surgeries such as autologous chondrocyte transplantation. However, despite these advancements, infections associated with cartilage implants remain a persistent challenge, compromising the success of surgeries and patient recovery. To address these challenges, this review provides a comprehensive foundation for researchers interested in addressing infections in CTE. It begins by briefly outlining the major scaffolds currently used in CTE and distinguishing those with antimicrobial properties. Among the antimicrobial scaffolds identified, chitosan and chondroitin sulfate stand out for their promising compatibility and antibacterial properties. The review then explores additives that meet three essential criteria: compatibility with chondrocytes, suitability for use in CTE scaffolds, and antibacterial efficacy. Chitosan, zinc oxide, silver, and copper emerge as leading candidates due to their compatibility with chondrocytes and proven antibacterial capabilities. Importantly, the criteria used in this review were chosen to provide researchers with a practical and reliable starting point for immediate application. However, it is acknowledged that other promising antibacterial modifications such as fabrication processes and additives such as bioactive glass and graphene oxide, which may not fit these criteria, also hold potential for future research and innovation. This review underscores the need for further research and development to enhance infection control measures and improve patient outcomes.