Fabrication Of Advanced Devices Research Articles

Chitosan Oligosaccharide Laser Lithograph: A Facile Route to Porous Graphene Electrodes for Flexible On-Chip Microsupercapacitors.

In this study, a convenient chitosan oligosaccharide laser lithograph (COSLL) technology was developed to fabricate laser-induced graphene (LIG) electrodes and flexible on-chip microsupercapacitors (MSCs). With a simple one-step CO2 laser, the pyrolysis of a chitosan oligosaccharide (COS) and in situ welding of the generated LIGs to engineering plastic substrates are achieved simultaneously. The resulting LIG products display a hierarchical porous architecture, excellent electrical conductivity (6.3 Ω sq-1), and superhydrophilic properties, making them ideal electrode materials for MSCs. The pyrolysis-welding coupled mechanism is deeply discussed through cross-sectional analyses and finite element simulations. The MSCs prepared by COSLL exhibit considerable areal capacitance of over 4 mF cm-2, which is comparable to that of the polyimide-LIG-based counterpart. COSLL is also compatible with complementary metal-oxide-semiconductor (CMOS) and micro-electro-mechanical system (MEMS) processes, enabling the fabrication of LIG/Au MSCs with comparable areal capacitance and lower internal resistance. Furthermore, the as-prepared MSCs demonstrate excellent mechanical robustness, long-cycle capability, and ease of series-parallel integration, benefiting their practical application in various scenarios. With the use of eco-friendly biomass carbon source and convenient process flowchart, the COSLL emerges as an attractive method for the fabrication of flexible LIG on-chip MSCs and various other advanced LIG devices.

Advancing Tissue Culture with Light-Driven 3D-Printed Microfluidic Devices.

Three-dimensional (3D) printing presents a compelling alternative for fabricating microfluidic devices, circumventing certain limitations associated with traditional soft lithography methods. Microfluidics play a crucial role in the biomedical sciences, particularly in the creation of tissue spheroids and pharmaceutical research. Among the various 3D printing techniques, light-driven methods such as stereolithography (SLA), digital light processing (DLP), and photopolymer inkjet printing have gained prominence in microfluidics due to their rapid prototyping capabilities, high-resolution printing, and low processing temperatures. This review offers a comprehensive overview of light-driven 3D printing techniques used in the fabrication of advanced microfluidic devices. It explores biomedical applications for 3D-printed microfluidics and provides insights into their potential impact and functionality within the biomedical field. We further summarize three light-driven 3D printing strategies for producing biomedical microfluidic systems: direct construction of microfluidic devices for cell culture, PDMS-based microfluidic devices for tissue engineering, and a modular SLA-printed microfluidic chip to co-culture and monitor cells.

Controlling behaviour of transparency and absorption in three-coupled multiple quantum wells via spontaneously generated coherence

This article presents a coherent phenomenon called spontaneously generated coherence (SGC) under the regime of electromagnetically induced transparency (EIT) in a three-coupled multiple quantum wells. We demonstrate that the presence of SGC in these quantum wells lead to intriguing modifications in the transparency window within the absorption spectrum. At the same time, modification of the dispersive nature is also demonstrated which enables the feasibility of the system in diverse applications based on light propagation. The absorption and dispersion responses are found to be varied by the individual strength of the first and second control fields in presence as well as in absence of SGC in the EIT regime. The positional shifting of the transparency window and simultaneous modifications in the dispersive profiles by tuning the control field detunings of both the first and second control fields are also revealed. Some absorption and dispersion contours are illustrated for getting better insights into the modifications of the optical responses via SGC. Finally, by manipulating the strength of the SGC parameter, we observe the changes in the respective position of the transparency window and dispersion curve. It is expected that the current investigations will pave novel ways for innovative applications in quantum communications, and fabrication of advanced photonic devices.

Control of selective SiGe etching by enhanced formation of hydroxyl radicals and by surface passivation in peracetic acid solution

The selective etching of SiGe over Si is a crucial process in the fabrication of advanced 3D semiconductor devices. During the etching process, highly selective SiGe etching is required to obtain precise etch profiles. In this study, the enhancement of the selective SiGe etching in a peracetic acid (PAA) etchant solution by adding hydroxylamine and pentyl acetate was investigated. The addition of hydroxylamine increased the SiGe etching rate and SiGe/Si etching selectivity owing to the more vigorous oxidation of the SiGe surface produced by hydroxyl radicals. The SiGe/Si etching selectivity was also increased through the addition of pentyl acetate owing to the larger decrease in the Si etching rate when compared to that in SiGe. This is due to the stronger passivation effect of pentyl acetate on the Si surface, which suppresses its oxidation more effectively than on the SiGe surface. The SiGe etching rate and SiGe/Si etching selectivity were significantly increased from 223.3 nm/min and 125 to 310.8 nm/min and 557, respectively, through the simultaneous addition of hydroxylamine and pentyl acetate to the PAA etchant solution. Consequently, a mechanism for the selective etching of SiGe on vertically stacked SiGe/Si trench structures using the PAA etchant solution was proposed.

Nanoparticles bearing germanium based photoinitiators at their surface: Preparation and use in grafting-from photopolymerization reactions

In recent decades, there has been a growing interest in surface modifications utilizing “grafting-from” techniques within both industrial and academic fields. Among others, this technology continues to drive innovation in biomedicine, enabling the design and fabrication of advanced materials and devices with tailored properties for a wide range of applications, from regenerative medicine and drug delivery to diagnostics and therapeutics. This strategy relies on the covalent attachment of (photo)initiating species to surfaces. The coupled initiators are exploited to produce reactive sites such as radicals upon exposure to heat or light. Subsequently, polymerization reactions are induced, leading to surface coupled polymer brushes.In order to provide new perspectives in surface modification techniques, we present a novel and unique method for producing mesoporous organic/inorganic hybrid nanoparticles via the “grafting-from” method. This was accomplished by immobilizing a novel, low-toxic and visible light sensitive photoinitiator (based on triacylgermanium moieties) onto silica nanoparticles. Surface-initiated photopolymerizations of styrene and acrylate monomers were conducted to produce polymer shells on the surface of the nanoparticles. The grafted layers had a thickness in the range of 6–12 nm. Furthermore, the polymer grafting density is discussed in detail ranging between 0.17 and 0.23 chains per square nanometer.

Advancements in single-crystal silicon with elevated-laser-liquid-phase-epitaxy (ELLPE) for monolithic 3D ICs

In this study, we present a low thermal budget elevated-laser-liquid-phase-epitaxy technique designed for the precise fabrication of single-crystal islands (SCIs) intended for use in middle-end-of-line (MEOL) FinFETs. Each of these SCIs features a (100) orientation tended from Si seeding structure and is successfully integrated as channel materials in the MEOL circuit of a monolithic 3D IC (3DIC). This technique effectively mitigates the typical performance disparities associated with poly-Si channel materials in upper tiers, addressing a significant challenge in advanced electronic device fabrication and potentially enhancing the performance and reliability of MEOL FinFETs in monolithic 3DIC.

Conversion of silicon wafer type from perfect-interstitial to perfect-vacancy by rapid thermal process

Vacancies, self-interstitials, and Frenkel pairs represent the basic point defects in silicon single-crystals and are unavoidably introduced in the ingots during the manufacturing process. In semiconductor technology, several problems are caused by points defects that are not at thermodynamic equilibrium. For this reason, virtually defect-free silicon wafers having a small residual concentration of vacancies in the bulk (“Perfect-vacancy”, or Pv silicon) are solely used for the fabrication of advanced microelectronic devices, whereas similar wafers containing a residual concentration of silicon self-interstitials (Pi silicon) are often regarded as unsuitable substrates for device fabrication. This paper describes the possibility of using Pi silicon wafers, after their conversion to Pv, for those applications requiring only vacancy-rich perfect silicon as the substrate. The conversion from Pi to Pv is achieved in these wafers by using rapid thermal annealing at high temperature to produce Frenkel pairs first and to re-install a specific vacancy concentration in the bulk of the wafer later, thus reassigning a new Pv character to the silicon substrate.

Laser Etching Post‐Processing to Create Low‐Tortuosity Structured Electrodes for Advanced Sodium‐Ion Batteries

Constructing low‐tortuosity structure is a facile and effective strategy to significantly improve the electrochemical performances of thick electrodes of batteries. In this study, the low‐tortuosity structured electrodes with an array grooved structure are fabricated using a method of laser etching post‐processing, promoting excellent electrochemical performance of sodium‐ion batteries (SIBs). The effects of laser post‐processing parameters including the etching shape, interval, and scan number on the structures and electrochemical performances of the prepared electrodes are investigated. Results show that the array grooved structures of the laser‐treated electrodes not only reduce the tortuosity to enhance the ion transfer efficiency, but also provide extra space to accommodate more electrolyte, which helps strengthen the electrochemical reaction kinetics of the electrodes. The proposed electrode with a parallelogram etching shape, an interval of 0.1 mm, and a scan number of 10 can produce a high rate capacity of 120.7 mAh g−1 at 500 mA g−1 and an outstanding cycle performance with a high capacity maintenance rate of 97.8% after 200 cycles. This study validates a new method to create low‐tortuosity electrodes for SIBs by optimizing the process parameter, which can be potentially extended to the fabrication of other advanced energy storage devices.

Advancing rural healthcare: A novel approach to designing blockchain-enabled IoB devices and integrating fuzzy intelligence systems for patient monitoring and record management

This research paper presents a novel approach to improving healthcare services in rural areas by leveraging the potential of Fuzzy Intelligence Systems, Internet of Bodies (IoB) devices, and Blockchain technology. It begins by exploring the design and development of a Blockchain-based Patients Record System (BPRS), which ensures secure, transparent, and tamper-proof storage of patient medical records. The paper then delves into the fabrication of advanced IoB devices, specifically designed to study and monitor the health of rural populations. These devices, integrated with Fuzzy Intelligence Systems, provide efficient and reliable data capture, interpretation, and decision-making support. The highlight of the study is the innovative integration of the IoB enabled Patient Monitoring System with the BPRS, which ensures real-time data synchronization and secure access to patient data for authorized personnel. The system collectively promotes efficient healthcare delivery, data privacy, and patient safety in rural areas.

Direct ink writing 3D printing of low-dimensional nanomaterials for micro-supercapacitors.

Micro-supercapacitors (MSCs) have attracted significant attention for potential applications in miniaturized electronics due to their high power density, rapid charge/discharge rates, and extended lifespan. Despite the unique properties of low-dimensional nanomaterials, which hold tremendous potential for revolutionary applications, effectively integrating these attributes into MSCs presents several challenges. 3D printing is rapidly emerging as a key player in the fabrication of advanced energy storage devices. Its ability to design, prototype, and produce functional devices incorporating low-dimensional nanomaterials positions it as an influential technology. In this review, we delve into recent advancements and innovations in micro-supercapacitor manufacturing, with a specific focus on the incorporation of low-dimensional nanomaterials using direct ink writing (DIW) 3D printing techniques. We highlight the distinct advantages offered by low-dimensional nanomaterials, from quantum effects in 0D nanoparticles that result in high capacitance values to rapid electron and ion transport in 1D nanowires, as well as the extensive surface area and mechanical flexibility of 2D nanosheets. Additionally, we address the challenges encountered during the fabrication process, such as material viscosity, printing resolution, and seamless integration of active materials with current collectors. This review highlights the remarkable progress in the energy storage sector, demonstrating how the synergistic use of low-dimensional nanomaterials and 3D printing technologies not only overcomes existing limitations but also opens new avenues for the development and production of advanced micro-supercapacitors. The convergence of low-dimensional nanomaterials and DIW 3D printing heralds the advent of the next generation of energy storage devices, making a significant contribution to the field and laying the groundwork for future innovations.

Microplasma Nanoengineering of Hybrid Plasmonic Nanostructures for Rapid and Ultrasensitive Surface-Enhanced Raman Scattering-Based Sensing

Surface-enhanced Raman scattering (SERS) is a useful analytical tool that allows ultrasensitive molecular-level detection through an enhanced electromagnetic field generated by plasmonic metal nanoparticles (MNPs), which is helpful for biomedical-based detection, environmental pollution monitoring and chemical industry. Recent study suggests that porous MNP with enhanced SERS active area and hybrid plasmonic nanostructures such as core-shell NPs and metal-semiconductor-based NPs with designed and controlled plasmonic properties can further improve the SERS responses.Here we report a microplasma nanoengineering of plasmonic nanostrutures including Au-Ag core-shell NPs, Ag-GQD nanohydrids, and porous Au nanosturtures for ultrasensitive SERS-based applications. Microplasmas are low-emperature plasmas that feature microscale dimensions and a unique high-energy-density and a nonequilibrium reactive environment, which makes them promising for the fabrication of advanced nanomaterials and devices for diverse applications. Detailed characterization indicates the microplasma-enable controllable-designed growth of plasmonic nanomaterial with heterostructure effect, the providing enhanced charge transportation , adsorption ability or forster resonance energy transfer during Raman scattering. To understand the plasmonic effect, we use 3D confocal microRaman scattering study that shows that a large SERS volume was formed in the as-fabricated SERS-active substrates, leading to significant SERS properties of low limit of detection and high enhanced factor (EF) with the Rhodamine 6G (R6G) as the Raman probe. Furthermore, we also used the biomoleculars , medicines , and dyes as the target molecule. Our work not only provides environmentally friendly fabrication technique with strong potential for the design and growth of the nanostructure but also the fundamental insight of plasmonic nanostrutures for emerging applications including nanocataysis, sustainable energy, and biomedical imaging.

Photophoretic deposition and separation of aerosol-synthesized single-walled carbon nanotubes

We report a novel, dry, and clean method to directly deposit single-walled carbon nanotubes (SWCNTs) onto a desired substrate with the photophoresis phenomenon. We demonstrate the photophoresis method to be convenient and reproducible to deposit low-bundled nanotubes to form either non-percolating or continuous networks with controlled SWCNT density and surface distribution. Employing the structure-dependent optical features of the nanotubes, we show the correlation between the light source spectrum and the configuration of the deposited SWCNTs due to the selective light interaction with SWCNTs of certain chiralities. Thus, photophoretic deposition is a promising method for the fabrication of various advanced devices, such as electrically driven single-photon emitters or field-effect transistors from semiconducting SWCNTs with a desired electronic structure.

Printable, adhesive, and self-healing dry epidermal electrodes based on PEDOT:PSS and polyurethane diol

Printable, self-healing, stretchable, and conductive materials have tremendous potential for the fabrication of advanced electronic devices. Poly(3,4-ethylenedioxithiopene) doped with polystyrene sulfonate (PEDOT:PSS) has been the focus of extensive research due to its tunable electrical and mechanical properties. Owing to its solution-processability and self-healing ability, PEDOT:PSS is an excellent candidate for developing printable inks. In this study, we developed printable, stretchable, dry, lightly adhesive, and self-healing materials for biomedical applications. Polyurethane diol (PUD), polyethylene glycol, and sorbitol were investigated as additives for PEDOT:PSS. In this study, we identified an optimal printable mixture obtained by adding PUD to PEDOT:PSS, which improved both the mechanical and electrical properties. PUD/PEDOT:PSS free-standing films with optimized composition showed a conductivity of approximately 30 S cm−1, stretchability of 30%, and Young’s modulus of 15 MPa. A low resistance change (<20%) was achieved when the strain was increased to 30%. Excellent electrical stability under cyclic mechanical strain, biocompatibility, and 100% electrical self-healing were also observed. The potential biomedical applications of this mixture were demonstrated by fabricating a printed epidermal electrode on a stretchable silicone substrate. The PUD/PEDOT:PSS electrodes displayed a skin-electrode impedance similar to commercially available ones, and successfully captured physiological signals. This study contributes to the development of improved customization and enhanced mechanical durability of soft electronic materials.

N-type organic phototransistors based on PTCDA single crystals for broadband imaging

Organic single crystals (OSCs) herald new opportunities for the fabrication of advanced optoelectronic devices, especially for flexible and wearable devices, owing to their unique material properties including high mobility and intrinsic flexibility. Up to now, though the electrical characteristics have been a breakthrough in OSCs, the devices have not been fully optimized for inherent photoelectric properties, and their photoresponse characteristics are also scarcely satisfactory, especially for the n-type organic materials. In this work, we prepared a high-performance organic phototransistor employing the air-stable PTCDA single crystal, grown by a simple microspacing in-air sublimation technique. The responsivity and photosensitivity of the device can reach up to 180 A/W and 103 for 532 nm illumination, with also a good response speed (rise and decay times less than 1 and 2 ms). In addition, we demonstrated several high-resolution imaging in this organic transistor. Our results demonstrated that the high-quality n-type organic single crystal is also a promising candidate for future high-performance photodetector and imaging applications.

Synthesis Strategies and Nanoarchitectonics for High‐Performance Transition Metal Dichalcogenide Thin Film Field‐effect Transistors

AbstractTransition metal dichalcogenides (TMDC) exhibit highly superior electrical properties and are typically obtained through mechanical exfoliation. This method has significant limitations, however, such as patterning issues and non‐uniformity, which hinder their application in integrated circuits as transistors and array pixel displays. To overcome these challenges, various large‐scale deposition methods have been developed. In this review, we introduce five major methods for TMDC deposition: chemical vapor deposition, physical vapor deposition, atomic layer deposition, pulsed laser deposition, and ink‐jet printing. An overview of each method is provided in the following order: surface analysis, electrical characteristics, and limitations of each method are discussed. Furthermore, we present three key strategies for an advanced device fabrication using the discussed deposition methods. By implementing these strategies, we can accelerate the development of highly crystalline and scalable TMDC thin films, which are essential for producing advanced electronic devices with improved performance. Owing to recent technological advancements, TMDC devices have the potential to become the leading material for next‐generation semiconductor devices. These devices can be specifically designed and optimized for innovative applications.

Heading toward Miniature Sensors: Electrical Conductance of Linearly Assembled Gold Nanorods.

Metal nanoparticles are increasingly used as key elements in the fabrication and processing of advanced electronic systems and devices. For future device integration, their charge transport properties are essential. This has been exploited, e.g., in the development of gold-nanoparticle-based conductive inks and chemiresistive sensors. Colloidal wires and metal nanoparticle lines can also be used as interconnection structures to build directional electrical circuits, e.g., for signal transduction. Our scalable bottom-up, template-assisted self-assembly creates gold-nanorod (AuNR) lines that feature comparably small widths, as well as good conductivity. However, the bottom-up approach poses the question about the consistency of charge transport properties between individual lines, as this approach leads to heterogeneities among those lines with regard to AuNR orientation, as well as line defects. Therefore, we test the conductance of the AuNR lines and identify requirements for a reliable performance. We reveal that multiple parallel AuNR lines (>11) are necessary to achieve predictable conductivity properties, defining the level of miniaturization possible in such a setup. With this system, even an active area of only 16 µm2 shows a higher conductance (~10-5 S) than a monolayer of gold nanospheres with dithiolated-conjugated ligands and additionally features the advantage of anisotropic conductance.

Role of Tellurium Ions for Electrochemically Synthesized Zinc Telluride 2D Structures on Nonconductive Substrate

AbstractAlthough electrodeposition has emerged as a promising approach to make metal chalcogenide nanostructures, it has an underlying issue of exfoliating the deposits affixed to a conductive substrate, which is inevitable to transfer electrons for a reduction reaction, for precise characterization and advanced device fabrication. Herein, direct electrodeposition of metal chalcogenides on a silicon dioxide (SiO2) insulator and its device applications for a back‐gated field‐effect‐transistor and a nitrogen dioxide gas sensor are investigated. Tellurium metal nanorods are deposited on SiO2 by the redox reaction of tellurium substances in the electrolyte. Using underpotential deposition, zinc telluride (ZnTe) is propagated onto tellurium sites, which has deposited on SiO2, bridging the microgap electrode on SiO2. The growth mechanisms of ZnTe on the SiO2 are also explored. This finding addresses the major challenge associated with the electrodeposition by the successful deposition of complex chalcogenides on an insulating substrate that expands its applications in fields for advanced electronics.

Achieving High Permittivity Paraelectric Behavior in Mesogen-Free Sulfonylated Chiral Polyethers with Smectic C Liquid Crystalline Self-Assembly

Ferroelectric liquid crystalline polymers (LCPs) with a high spontaneous polarization (Ps) are of great interest for the fabrication of advanced electronic devices. However, conventional ferroelectric LCPs typically exhibit low spontaneous polarization, only around 1 mC/m2. To increase the orientational polarization for ferroelectric LCPs, in this work, we designed mesogen-free comb-shaped LCPs based on isotactic polyepichlorohydrin, which contained highly dipolar sulfonyl groups (dipole moment of 4.5 Debye) in the side chains. The goal was to increase dipole density and induce ferroelectric switching. In this new series of mesogen-free LCPs, the sulfonyl groups were first moved away from the main chain to mitigate strong dipole–dipole interactions. Second, methyl-branched alkyl side chains were implemented to decrease the crystallizability and induce the Smectic C (SmC) self-assembly. Intriguingly, these SmC samples, for the first time, exhibited typical paraelectric behavior (i.e., slim S-shaped single hysteresis loops) with a high dielectric constant in the range of 20–30. Learning from the knowledge obtained from this study, we will be able to design new mesogen-free LCPs with tailor-made dipole–dipole interactions and realize ferroelectricity.

Spatially Templated Nanolines of Ru and RuO2 by Sequential Infiltration Synthesis

Nanoscale patterning of inorganics is crucial for the fabrication of advanced electronic, photonic, and energy devices. The emerging sequential infiltration synthesis (SIS) method fabricates nanofeatures by block-selective vapor-phase growth in block copolymer templates with tunable patterns. Yet, SIS has been demonstrated mainly for Al2O3 and a few other metal oxides, while deriving metal nanostructures from a single SIS process is a challenge. Here, we present SIS of the Ru metal in polystyrene-block-polymethyl methacrylate (PS-b-PMMA) templates without any pretreatment, using alternating infiltration of RuO4 and H2. RuO4 interacts selectively and strongly with the aromatic C═C and C–H groups in PS, leaving the PMMA domains inert. Density functional theory calculations corroborate that the PS–RuO4 interaction is energetically favorable, with a calculated interaction energy of −1.65 eV, whereas for PMMA–RuO4, the calculated energy of −0.05 eV indicates an unfavorable interaction. Morphological analysis on the di-BCP after the RuO4-H2 process indicates an increase in contrast as a function of SIS cycles and templated Ru incorporation. The crystalline nature of the Ru deposits is confirmed using grazing incidence wide-angle X-ray scattering. Plasma-aided removal of the organic components yields Ru nanolines with lateral dimensions of ca 20 nm. We further highlight the broad potential of RuO4 as a reactant for SIS by generating RuO2 nanopatterns via alternating RuO4 and methanol infiltration.

Carbon nanodots calibrated fluorescent probe of QD@amphiphilic polyurethane for ratiometric detection of Hg (II)

Because of its strong toxicity to the ecosystem and human beings, mercury is regarded as one of the most hazardous heavy metals. Among various fluorescent sensors that have been designed for Hg (II) detection, the probes showing Hg (II) concentration dependent ratiometric fluorescent responses normally exhibited improved analytical performance. Herein, we have synthesized series of amphiphilic polyurethane (PU) to encapsulate hydrophobic fluorescent quantum dots (QD) via the emulsion confinement self-assembly, leading to generation of QD@PU colloids whose red emission can be selectively quenched by Hg (II) among other metal ions. In order to further improve the Hg (II) detection performance of QD@PU probe, the green emitting carbon nanodots (CD) were synthesized and conjugated with QD@PU, resulting to formation of CD-QD@PU colloidal probe showing ratiometric fluorescent response towards Hg (II), which finally contributed to an enhanced sensitivity and wider linear range for Hg (II) detection. More interestingly, both QD@PU and CD-QD@PU doped stretchable PU membranes still hold naked eye discrimination for Hg (II). Basically, the current work revealed a universal protocol to prepare fluorescent probe for Hg (II) detection using PU and low dimensional fluorescent nanoparticles as building blocks, which will open new way for design and fabrication of other advanced sensors and analytical devices. • An amphiphilic block copolymer of polyurethane (PU) were synthesized. • PU was used to encapsulate fluorescent quantum dots (QD) to obtain QD@PU colloids. • The fluorescence of QD@PU colloids can be selectively quenched by Hg (II). • Nitrogen and sulfur co-doped carbon nanodots (CD) was synthesized. • The CD-QD@PU probe allows specific detection of Hg (II) down to 10.5 nM.