High-yield Fabrication Research Articles

High-yield biogenic fabrication and phytochemical screening of silver nanomaterials (AgNMs) from Kaempferia parviflora rhizome extract

High-yield biogenic fabrication and phytochemical screening of silver nanomaterials (AgNMs) from Kaempferia parviflora rhizome extract

Gilded vaterite particles: Synthesis, optical characterization, and label-free imaging

Inorganic nanoparticles are capable of accommodating multiple biomedical modalities, making them prime candidates for realizing light-responsive theranostic carriers. Within this realm, merging the benefits of diverse platforms promises the development of new functionalities, broadening the range of applications. While vaterite, a polymorph of calcium carbonate, is known for its structural versatility and chemical modifiability, gold nanoparticles are recognized for their unique optical properties. Here we explore a new mesoscopic particle, gilded vaterite, which encompasses the advantages of both platforms. A flexible synthesis method is developed and optimized, demonstrating the capability to obtain high-yield fabrication of vaterite particles with controllable form factors alongside tailored surface coverage with gold. Uniform reproducible distributions of gold nanoparticles of up to 80 nm in diameter, with coverage above 40%, were demonstrated. Optical properties of gilded vaterite particles were explored, revealing strong peaks, which built up owing to the resonant hybridization of near-field coupled plasmonic resonances. Confocal microscopy of cells was utilized to explore potential applications of gilded vaterite with tunable optical properties in the realm of label-free imaging. Strong light scattering from vaterite carriers, taken up by cells, alongside the fluorescence from stained cells, was observed via reflectance confocal microscopy. This dual-channel approach allows for simultaneous observation of the particles and their biological environment. Tunable optical and biochemical properties of gilded vaterite promote this perspective platform towards accommodating new modalities and thus becoming an intrinsically optical-responsive multifunctional system.

High-yield fabrication of monodisperse multilayer nanofibrous microparticles for advanced oral drug delivery applications

Recent advances in the use of nano- and microparticles in drug delivery, cell therapy, and tissue engineering have led to increasing attention towards nanostructured microparticulate formulations for maximum benefit from both nano- and micron sized features. Scalable manufacturing of monodisperse nanostructured microparticles with tunable size, shape, content, and release rate remains a big challenge. Current technology, mainly comprises complex multi-step chemical procedures with limited control over these aspects. Here, we demonstrate a novel technique for high-yield fabrication of monodisperse monolayer and multilayer nanofibrous microparticles (MoNami and MuNaMi respectively). The fabrication procedure includes sequential electrospinning followed by micro-cutting at room temperature and transfer of particles for collection. The big advantage of the introduced technique is the potential to apply several polymer-drug combinations forming multilayer microparticles enjoying extracellular matrix (ECM)-mimicking architecture with tunable release profile. We demonstrate the fabrication and study the factors affecting the final three-dimensional structure. A model drug is encapsulated into a three-layer sheet (PLGA-pullulan-PLGA), and we demonstrate how the release profile changes from burst to sustain by simply cutting particles out of the electrospun sheet. We believe our fabrication method offers a unique and facile platform for realizing advanced microparticles for oral drug delivery applications.

Multilevel design and construction in nanomembrane rolling for three-dimensional angle-sensitive photodetection

Releasing pre-strained two-dimensional nanomembranes to assemble on-chip three-dimensional devices is crucial for upcoming advanced electronic and optoelectronic applications. However, the release process is affected by many unclear factors, hindering the transition from laboratory to industrial applications. Here, we propose a quasistatic multilevel finite element modeling to assemble three-dimensional structures from two-dimensional nanomembranes and offer verification results by various bilayer nanomembranes. Take Si/Cr nanomembrane as an example, we confirm that the three-dimensional structural formation is governed by both the minimum energy state and the geometric constraints imposed by the edges of the sacrificial layer. Large-scale, high-yield fabrication of three-dimensional structures is achieved, and two distinct three-dimensional structures are assembled from the same precursor. Six types of three-dimensional Si/Cr photodetectors are then prepared to resolve the incident angle of light with a deep neural network model, opening up possibilities for the design and manufacturing methods of More-than-Moore-era devices.

Low-temperature high-yield fabrication of colloidal Si quantum dots with in situ tunability for luminescence band from red to green

Low-temperature high-yield fabrication of colloidal Si quantum dots with <i>in situ</i> tunability for luminescence band from red to green

Multi-scale alignment to buried atom-scale devices using Kelvin probe force microscopy

Abstract Fabrication of quantum devices by atomic-scale patterning with scanning tunneling microscopy (STM) has led to the development of single/few atom transistors, few-donor/quantum dot devices for spin manipulation, and arrayed few-donor devices for analog quantum simulation. We have developed atomic precision lithography, dopant incorporation, device encapsulation, ex situ device re-location, and contact processes to enable high-yield device fabrication. In this work, we describe a multiscale alignment strategy using Kelvin probe force microscopy to enable the alignment of buried device components to electronic support structures such as source/drain leads, in-plane and top gates, and waveguides while preserving flexibility in the placement of fabricated STM patterns. The required spatial accuracy to bridge the sub-micrometer scale central region of the device to millimeter scale large wire-bond pads is achieved through a multi-step alignment process at various stages of fabrication, including atom-scale device fabrication using STM, re-location and registration, and electron beam lithography for contact leads and pads. This alignment strategy allows imaging small device regions as well as large-scale fiducial marks, thereby bridging the gap from nanometer STM patterns to the millimeter-scale electrical contact fabrication with a 95% yield on more than 150 devices fabricated to date.

Superconducting wide strip photon detector with high critical current bank structure

The single-photon detector is an essential technology in photonic quantum information science and technology. Large-scale photonic quantum computers and quantum networks inevitably require numerous high-performance single-photon detectors. Superconducting nanostrip single-photon detectors (SNSPDs) using around 100-nm-wide nanostrips are promising technologies with high detection efficiency, low dark count, and low jitter, but there has been room for evolution in terms of polarization dependence and productivity. Using wide strips with widths of tens of micrometers provides polarization-independent high detection efficiency and high-yield fabrication using high-throughput photolithography with submicron resolution. However, detecting photons with such wide strips has been challenging due to rapidly increasing intrinsic dark counts caused by the uneven distribution of the superconducting current in the strip. Here, we present a novel superconducting wide strip photon detector (SWSPD) with a high critical current bank (HCCB) structure. This new strip structure suppresses the intrinsic dark counts and provides highly efficient photon detection in the wide strips. We have simultaneously achieved a polarization-independent detection efficiency of over 78% for 1550-nm wavelength photons, a low dark count rate (DCR) of ∼80 cps, and a low jitter of 29.8 ps using a 20-µm-wide SWSPD with the HCCB structure. This result paves the way for a new class of photon detectors using ultra-wide superconducting strips. These photon detectors with excellent productivity and polarization-independent high detection performances would boost the advance of large-scale photonic quantum technologies.

Enhanced mechanical property through high-yield fabrication process with double laser scanning method in two-photon lithography

Two-photon lithography (TPL) is a representative fabrication process for micro 3D structures with a sub-micron fabrication resolution. As the TPL process is developed and commercialized, the TPL process requires higher process yield to be a considered reliable manufacturing technique for mass production. However, delamination is one of the main factors that reduce the yield of the TPL process. In this study, a double-step laser scanning method is proposed as a reliable high-yield TPS process to reduce the delamination effect. The method entails a simple process that polymerizes the initial interfacial layer between the structures and substrate twice. The additional laser scanning step induces a strong crosslinking in the polymer, and thereby preventing swelling and delamination. Furthermore, the effectiveness of the method is evaluated with large-scale microlens arrays. Although the process time is slightly increased, the process yield is significantly improved through the use of the double-step laser scanning method. Hence, the double-step laser scanning process can be employed as a reliable additive manufacturing process for various 3D microscale devices, and more importantly, it can be used to increase the manufacturing yield through the reduction of defects caused by surface delamination.

Ultra-small high‐temperature pressure sensor chips fabricated in single‐layer (111) SOI wafers

This paper presents a 0.5 mm × 0.5 mm tiny-sized high-temperature piezoresistive pressure sensor fabricated with a thin-film under bulk single-sided micromachining process from the front-side of single-layer (111) silicon on insulator (SOI) wafer. The (111)-device layer of the SOI wafer is specifically selected to optimize the piezoresistor performance where the SiO2 buried layer isolates the piezoresistors from the handle substrate. And the (111)-handle layer is employed to subtly construct a single-crystalline-silicon beam-island combining with a very thin but uniform poly-silicon diaphragm for realization of both low nonlinearity and high sensitivity. Without double-sided micromachining process and wafer bonding used, a tiny sensor-chip size of 0.5 mm × 0.5 mm is achieved, which is required in wind-tunnel systems for measuring pressure distribution at high temperature. The testing results of the fabricated sensor show high sensitivity of 0.15 mV V−1 kPa−1 for 150 kPa measure range and satisfactory linearity of ±0.11% FS (full scale) at ambient temperature. At 350 °C, the overall accuracy is 0.17% FS and the thermal hysteresis is 0.22% FS. The temperature coefficient of zero-point offset of the sensor is tested as low as 0.01% °C−1 FS and the temperature coefficient of sensitivity is −0.07% °C−1 FS within the whole temperature range from −55 °C to 350 °C. Featuring the advantages of high accuracy and high-yield low-cost fabrication, the tiny-sized high-temperature pressure sensors exhibit promising perspectives in the field of aerospace industry including wind-tunnel applications.

Multipurpose active scanning probe cantilevers for near-field spectroscopy, scanning tunnel imaging, and atomic-resolution lithography

In this work, we report progress on developing a multipurpose scanning probe cantilever applying gallium nitride nanowires as the probe tip. Gallium nitride nanowires possess high potential as probes due to their straight profile, tunable electrical and optical properties, high Young’s Modulus, durability, and high-yield fabrication process. Their wide bandgap enables them to be pumped to emit ultraviolet pulses which can be used for optical imaging and spectroscopy. They can be doped during growth to be electrically conductive, and their sharp tips obtained during epitaxial growth enable confinement of a high electric field at tip–sample interface. Their sharp tips are obtained during fabrication by their epitaxial growth which eliminates the need for postprocess sharpening that is typically required for standard STM tips. We present results of using gallium nitride nanowires for scanning tunnel microscopy applications of atomic-resolution imaging and lithography, and atomic force microscopy applications of imaging and lithography in vacuum and atmospheric environments.

Fast and high-yield fabrication of axially symmetric ion-trap needle electrodes via two step electrochemical etching.

Despite the progress in building sophisticated microfabricated ion traps, Paul traps employing needle electrodes retain their significance due to the simplicity of fabrication while producing high-quality systems suitable for quantum information processing, atomic clocks, etc. For low noise operations such as minimizing "excess micromotion," needles should be geometrically straight and aligned precisely with respect to each other. Self-terminated electrochemical etching, previously employed for fabricating ion-trap needle electrodes, employs a sensitive and time-consuming technique, resulting in a low success rate of usable electrodes. Here, we demonstrate an etching technique for the quick fabrication of straight and symmetric needles with a high success rate and a simple apparatus with reduced sensitivity to alignment imperfections. The novelty of our technique comes from using a two-step approach employing turbulent etching for fast shaping and slow etching/polishing for subsequent surface finish and tip cleaning. Using this technique, needle electrodes for an ion trap can be fabricated within a day, significantly reducing the setup time for a new apparatus. The needles fabricated via this technique have been used in our ion trap to achieve trapping lifetimes of several months.

Ullmann-Like Covalent Bond Coupling without Participation of Metal Atoms.

Ullmann-like on-surface synthesis is one of the most appropriate approaches for the bottom-up fabrication of covalent organic nanostructures and many successes have been achieved. The Ullmann reaction requires the oxidative addition of a catalyst (a metal atom in most cases): the metal atom will insert into a carbon-halogen bond, forming organometallic intermediates, which are then reductively eliminated and form C-C covalent bonds. As a result, traditional Ullmann coupling involves reactions of multiple steps, making it difficult to control the final product. Moreover, forming the organometallic intermediates will potentially poison the metal surface catalytic reactivity. In the study, we used the 2D hBN, an atomically thin sp2-hybridized sheet with a large band gap, to protect the Rh(111) metal surface. It is an ideal 2D platform to decouple the molecular precursor from the Rh(111) surface while maintaining the reactivity of Rh(111). We realize an Ullmann-like coupling of a planar biphenylene-based molecule, i.e., 1,8-dibromobiphenylene (BPBr2), on an hBN/Rh(111) surface with an ultrahigh selectivity of the biphenylene dimer product, containing 4-, 6-, and 8-membered rings. The reaction mechanism, including electron wave penetration and the template effect of the hBN, is elucidated by combining low-temperature scanning tunneling microscopy and density functional theory calculations. Our findings are expected to play an essential role regarding the high-yield fabrication of functional nanostructures for future information devices.

High-performance waveguide coupled Germanium-on-silicon single-photon avalanche diode with independently controllable absorption and multiplication

Abstract Germanium-on-silicon (Ge-on-Si) single photon avalanche diodes (SPADs) have received wide attention in recent years due to their potential to be integrated with Si photonics. In this work, we propose and demonstrate a high-performance waveguide coupled Ge-on-Si separate-absorption-charge-multiplication SPAD with three electric terminals. By providing two separate voltage drops on the light absorption and multiplication regions, the drift and multiplication of carriers can be optimized separately. This indeed improves the freedom of voltage regulation for both areas. Moreover, thanks to the separate controlling, doping profile of the charge layer is greatly released compared to that of the conventional device because of the flexible carrier injection. In this scenario, the dark counts of the detector can be largely reduced through decreasing the electric field on the sidewalls of the Ge absorption region without affecting the detection efficiency. The proposed SPAD exhibits a high on-chip single photon detection efficiency of 34.62% and low dark count rates of 279 kHz at 1310 nm with the temperature of 78 K. The noise equivalent power is as low as 3.27 × 10−16 WHz−1/2, which is, to the best of our knowledge, the lowest of that of the reported waveguide coupled Ge-on-Si SPADs. This three-terminal SPAD enables high-yield fabrication and provides robust performance in operation, showing a wide application prospect in applications such as on-chip quantum communication and lidar.

High-yield fabrication of electromechanical devices based on suspended Ti3C2Tx MXene monolayers.

MXenes, two-dimensional transition metal carbides, nitrides, and carbonitrides, are known for their exceptional electronic and mechanical properties. Yet, the experimental efforts toward the realization of MXene-based nanoelectromechanical systems (NEMS) combining electrical and mechanical functionalities of MXenes at the nanoscale remain very limited. Here, we demonstrate a high-yield fabrication of the electromechanical devices based on individual suspended monolayer MXene flakes. We employed Ti3C2Tx, the most popular MXene material to date, that can be produced as high-quality micrometer-scale monolayer flakes with a high electrical conductivity of over 10 000 S cm-1 and a high effective Young's modulus of about 330 GPa. These Ti3C2Tx flakes can be transferred over prefabricated trenches in a Si/Si3N4 substrate at a high yield, potentially enabling fabrication of hundreds of electromechanical devices based on suspended MXene monolayers. We demonstrate very clean, uniform, and well-stretched membranes with different dimensions, with Ti3C2Tx flakes suspended over trenches with gaps ranging from 200 nm to 2 μm. The resulting Ti3C2Tx monolayer membranes were electrostatically actuated, while their vertical displacement was monitored using a tip of an atomic force microscope (AFM). The devices reliably responded to the electrostatic actuation in ambient conditions over multiple cycles and with different measurement parameters, such as AC frequency, AC voltage amplitude, and AFM tip loading force. The demonstration of the high-yield fabrication of working electromechanical devices based on suspended Ti3C2Tx MXene membranes at the ultimate monolayer limit paves the way for the future exploration of the potential of MXenes for NEMS applications.

High-yield aqueous synthesis of partial-oxidized black phosphorus as layered nanodot photocatalysts for efficient visible-light driven degradation of emerging organic contaminants

The layered nanodot derived from 2D materials is an emerging member of the advanced functional material family. However, its development in applications is still facing inevitable challenges, and one of them is the synthesis strategy with environmental consideration. Herein, we report an aqueous strategy for high-yield fabrication of black phosphorus (BP) layered nanodots. Without using any organic solvent, the initial red phosphorus (RP) fine powder is successfully converted to BP nanostructures at 180–205 °C under the low pressure of 2.7–7.8 MPa and the high yield of 78% is achieved. The synthesized BP nanodots are partial-oxidized, and demonstrate proficient photocatalytic abilities in the visible-light driven degradation of emerging organic contaminants. The photocatalytic mechanism of BP nanodots is dependent on the specific electronic band structure with an acceptor energy level at 0.6 eV above the valence band. The first principle calculation reveals that the surface oxidation layer assists the passivation by hydrogen in aqueous circumstance and establishes the receptor function of BP nanodots. Therefore, our study not only accomplishes a novel route for the environment-friendly fabrication of BP layered nanodot photocatalysts for efficient degradation of emerging organic contaminants, but also contributes to the in-depth understanding of layered nanodots.

Large-Scale, High-Yield Laser Fabrication of Bright and Pure Single-Photon Emitters at Room Temperature in Hexagonal Boron Nitride.

Single-photon emitters (SPEs) play an important role in many optical quantum technologies. However, an efficient large-scale approach to the generation of high-quality SPE arrays remains an elusive goal at room temperature. Here, we demonstrate a scalable method of generating SPE arrays in hexagonal boron nitride (hBN) with high yield, brightness, and purity using single-pulse irradiation by a femtosecond laser. Our use of a single pulse per defect pattern minimized heat-related damages and improved the purity of SPEs compared with the previous laser-based approaches. Under the optimized fabrication and post-treatment conditions, SPE arrays were successfully generated from the 3.0 μm defect patterns with 43% yield, the highest among the 2D-based top-down approaches. Importantly, we found that 100% of the bright defect patterns are SPEs with g2(0) < 0.5 under such conditions, with the lowest g2(0) = 0.06 ± 0.03. Our SPEs also exhibit the highest brightness with the saturation SPE rate at 7.15 million counts per second. We believe that our overall high-quality and large-scale approach will help a wide range of applications of SPEs in on-chip quantum technologies.

Structural design and experimental analysis for AlN Lamb-wave resonators with different electrical boundary conditions

This paper presents an Aluminum Nitride (AlN) Lamb-wave resonator with high series-resonance quality factors (Qs) and good spectral purity. The influence of the interdigitated (IDT) electrode width and electrical boundary condition was theoretically analyzed to improve effective electro-mechanical coupling coefficient (k2eff) and spectral purity. According to the structural characteristic of the designed resonators, an advanced micro-manufacturing process was designed. A thermal oxide layer was employed to avoid the etching of inactive regions, which contributes to achieving the high Qs and high-yield fabrication. The measured results show the IDT-ground resonators with 12 μm and 6 μm electrode periods exhibit Qs values as high as 4457.1 and 2625.1, and k2eff of 0.61% and 0.33%, respectively. The IDT-IDT resonators have higher k2eff, but their Qs values are severely attenuated. Through observing their section morphologies, the measured shear angles of the bottom IDT electrodes with 12 μm and 6 μm periods are 54.95° and 65.7° respectively, and the surface AlN film has tiny cracks, which induces the performance deterioration of the IDT-IDT resonators. Moreover, the influence of the IDT material on the resonator’s performance was also analyzed.

A Two-Dimensional Superconducting Electron Gas in Freestanding LaAlO3/SrTiO3 Micromembranes

Freestanding oxide membranes constitute an intriguing material platform for new functionalities and allow integration of oxide electronics with technologically important platforms such as silicon. Sambri et al. recently reported a method to fabricate freestanding LaAlO3/SrTiO3 (LAO/STO) membranes by spalling of strained heterostructures. Here, we first develop a scheme for the high-yield fabrication of membrane devices on silicon. Second, we show that the membranes exhibit metallic conductivity and a superconducting phase below ∼200 mK. Using anisotropic magnetotransport we extract the superconducting phase coherence length ξ ≈ 36-80 nm and establish an upper bound on the thickness of the superconducting electron gas d ≈ 17-33 nm, thus confirming its two-dimensional character. Finally, we show that the critical current can be modulated using a silicon-based backgate. The ability to form superconducting nanostructures of LAO/STO membranes, with electronic properties similar to those of the bulk counterpart, opens opportunities for integrating oxide nanoelectronics with silicon-based architectures.

Life Cycle Assessment-Based Comparative Study between High-Yield and "Standard" Bottom-Up Procedures for the Fabrication of Carbon Dots.

Carbon dots (CDs) are carbon-based nanomaterials with remarkable properties that can be produced from a wide variety of synthesis routes. Given that “standard” bottom-up procedures are typically associated with low synthesis yields, different authors have been trying to devise alternative high-yield fabrication strategies. However, there is a doubt if sustainability-wise, the latter should be really preferred to the former. Herein, we employed a Life Cycle Assessment (LCA) approach to compare and understand the environmental impacts of high-yield and “standard” bottom-up strategies, by applying different life cycle impact assessment (LCIA) methods. These routes were: (1) production of hydrochar, via the hydrothermal treatment of carbon precursors, and its alkaline peroxide treatment into high-yield CDs; (2) microwave treatment of carbon precursors doped with ethylenediamine; (3) and (6) thermal treatment of carbon precursor and urea; (4) hydrothermal treatment of carbon precursor and urea; (5) microwave treatment of carbon precursor and urea. For this LCA, four LCIA methods were used: ReCiPe, Greenhouse Gas Protocol, AWARE, and USEtox. Results identified CD-5 as the most sustainable synthesis in ReCiPe, Greenhouse Gas Protocol, and USEtox. On the other hand, in AWARE, the most sustainable synthesis was CD-1. It was possible to conclude that, in general, high-yield synthesis (CD-1) was not more sustainable than “standard” bottom-up synthesis, such as CD-5 and CD-6 (also with relatively high-yield). More importantly, high-yield synthesis (CD-1) did not generate much lower environmental impacts than “standard” approaches with low yields, which indicates that higher yields come with relevant environmental costs.

Efficient golden gate assembly of DNA constructs for single molecule force spectroscopy and imaging.

Single-molecule techniques such as optical tweezers and fluorescence imaging are powerful tools for probing the biophysics of DNA and DNA-protein interactions. The application of these methods requires efficient approaches for creating designed DNA structures with labels for binding to a surface or microscopic beads. In this paper, we develop a simple and fast technique for making a diverse range of such DNA constructs by combining PCR amplicons and synthetic oligonucleotides using golden gate assembly rules. We demonstrate high yield fabrication of torsionally-constrained duplex DNA up to 10 kbp in length and a variety of DNA hairpin structures. We also show how tethering to a cross-linked antibody substrate significantly enhances measurement lifetime under high force. This rapid and adaptable fabrication method streamlines the assembly of DNA constructs for single molecule biophysics.