Array Device Research Articles

Bias-Switchable Photodetection and Photosynapse Dual-Functional Devices Based on 2D Perovskite/Organic Heterojunction for Imaging-to-Recognition Conversion.

Optoelectronic devices with imaging and recognition capabilities are crucial for developing artificial visual system (AVS). Bias-switchable photodetection and photosynaptic devices have been developed using 2D perovskite oxide/organic heterojunctions. This unique structure allows for modulated carrier dynamics under varied bias conditions, enabling the devices to function as photodetectors without bias and as photosynapses with bias. At zero bias, the device achieves high responsivity (≈0.36 A W-1 at 320 nm) and rapid response speed (0.57 s). Under a -0.5 V bias, it exhibits persistent photoconductivity (PPC), resulting in neuromorphic synaptic behaviors with a paired-pulse facilitation (PPF) index exceeding 300%. Moreover, an 8 × 8 sensor array demonstrates image sensing and memory capabilities, showing in situ enhanced imaging when switching the bias from 0 to -0.5 V, and over 200 s of image memory. The image processing and recognition abilities are further explored by constructing an AVS using a 28 × 28 device array combined with an artificial neural network (ANN). The adjustable synaptic weight under different reverse biases allowed for optimized simulated recognition, achieving an accuracy of 92% after 160 training epochs. This work presents a novel method for creating dual-functional photodetection and photosynaptic devices, paving the way for a more integrated and efficient AVS.

Sustainable Fabrication and Transfer of High-Precision Nanoparticle Arrays Using Recyclable Chemical Pattern Templates.

Nanoparticle (NP) arrays, particularly those with plasmonic properties, have diverse applications in electronics, photonics, catalysis, and biosensing, but their precise and scalable fabrication remains challenging. In this work, a facile chemical-based strategy is presented for the fabrication of precise NP patterns using a combination of soft thermal nanoimprinting and template-directed assembly. The approach enables the creation of well-defined NP arrays with single-particle resolution and yields over 99%, covering a diverse range of NP sizes from 30 to 150nm. These patterns can be transferred onto various substrates including semiconductors, insulators, 2D materials, and flexible polymers, maintaining high uniformity and repeatability for over 60 cycles with minimal degradation. Moreover, the method enables the fabrication of extensive NP arrays up to 1 cm2 with a positional accuracy of ±11 nm for 30nm NPs. As a result, the obtained silver NP arrays exhibit ultranarrow surface lattice resonances with a linewidth of 4nm and a quality factor (Q) of 216. The method offers new avenues for the creation of plasmonic NP arrays for flexible and wearable devices.

Highly dispersive multiplexed micromechanical device array for spatially resolved sensing and actuation

The powerful resource of parallelizing simple devices for realizing and enhancing complex operations comes with the drawback of multiple connections for addressing and controlling the individual elements. Here we report on a technological platform where several mechanical resonators can be individually probed and electrically actuated by using dispersive multiplexing within a single electrical channel. We demonstrate room temperature control of the individual device vibrational motion and spatially-resolved readouts. As the single elements have proven to be excellent bolometers and individual nodes for reservoir computing, our platform can be directly employed for single-channel addressing of multiple devices, with immediate applications for far-infrared cameras, spatial light modulators and recurrent neural networks operating at room temperature.

Robust Sodium Carboxymethyl Cellulose-Based Neuromorphic Device with High Biocompatibility Engineered through Molecular Polarization for the Emulation of Learning Behaviors in the Human Brain.

Sodium carboxymethyl cellulose (CMC-Na), derived from natural cellulose and frequently employed as a biocompatible coating, thus renders it an ideal component for the construction of highly biocompatible neuromorphic devices aimed at biomachine interfaces. Here, an array of Mo/CMC-Na/ITO neuromorphic devices is fabricated, with CMC-Na serving as the functional layer. The devices exhibit capabilities to emulate various synaptic learning rules and demonstrate high endurance performance among biomaterial-based electronics, achieving stability over 2 × 104 pulses. Then, simulations of human brain-inspired learning and forgetting paradigms are conducted, highlighting the versatility of the device array in mimicking learning processes. Applications in pattern recognition leverage "learning-forgetting" paradigms, showcasing the potential of the device in cognitive tasks. Electrical measurements elucidate the mechanism of molecular polarization rotation, which offers insights into the modulation of synaptic weights within biocompatible biomaterial-based devices. Furthermore, the biocompatible properties of the devices are evaluated using human embryonic kidney 293 cells, confirming their excellent biocompatibility. The biodegradability of the devices is assessed by using physical transient tests to evaluate their sustainability in biomedical applications. Such advances represent pivotal improvements in implantable bioinspired electronics and show potential in biomachine interface and cognitive computing applications.

Dual‐Layer‐Per‐Array Operation Using Local Polarization Switching of Ferroelectric Tunnel FETs for Massive Neural Networks

AbstractA novel dual‐layer‐per‐array (DLPA) operation is proposed and experimentally demonstrated by using ferroelectric tunnel field‐effect transistors (FeTFETs) as synaptic transistors for high‐density and low‐power neuromorphic computing applications for the first time. Through local polarization switching (LPS), two distinct synaptic weight sets are stored and processed by utilizing the symmetrical and independent forward and ambipolar current regions within a single FeTFET. The stored weights of each region are multiplied by input gate voltages in the two‐layer operation modes of TFETs: forward and ambipolar layer, enabling separate vector‐matrix multiplication (VMM) operations within a single device array and doubling computational density. It is expected that the DLPA operation of FeTFETs will facilitate the implementation of large neural networks by reducing the footprint of conventional neuromorphic hardware by 50%.

Gold‐Assisted Exfoliation of Large‐Area Monolayer Transition Metal Dichalcogenides: From Interface Properties to Device Applications

AbstractSemiconductor transition metal dichalcogenides (TMDs), such as MoS2, are currently regarded as key‐enabling materials for sub‐1 nm channel transistors, beyond‐complementary metal–oxide–semiconductor electronic and optoelectronic devices and sensors. Owing to this wide application potential, several bottom‐up and top‐down synthesis approaches for these materials have been explored so far. Despite the huge progresses in scalable deposition methods (such as chemical vapor deposition, metal–organic chemical vapor deposition), exfoliated layers from bulk crystals still represent the benchmark for record electronic properties of TMDs. Among exfoliation approaches, metal‐assisted mechanical exfoliation emerges as the most effective method to separate large‐area (mm2 to cm2) single‐crystalline monolayer membranes of TMDs (and many other 2D materials) from the parent bulk crystals. This paper reviews the state‐of‐the‐art in this field, from current understanding of MoS2 exfoliation mechanisms on Au (considered as a model system), to the main device applications of as‐exfoliated and transferred large‐area MoS2 membranes (including Au/MoS2/Au memristors, MoS2 photodetectors, and field‐effect transistors). Perspectives of this method in the realization of arrays of 2D heterojunction devices, including Moirè superlattice devices, and open challenges for its widespread application are finally discussed.

Integrating the Airway Lead structure into a large healthcare system to appraise the landscape of airway management resources

Airway Leads are clinicians who guide safe airway management institutionally and act as liaisons between the evolving airway management landscape and bedside clinicians. Internationally, resources produced by Airway Leads Networks aid clinicians in establishing emergency airway management protocols and making difficult airway equipment decisions. The creation of an Airway Leads Network within the United States' multi-payer healthcare system is ongoing, spearheaded nationally by groups such as the Society for Airway Management. We aimed to build a committee of airway leaders across the Yale New Haven Health system and to leverage this committee to appraise the airway equipment and personnel resources throughout the system. We identified key stakeholders in airway management across the healthcare system and administered a quality improvement survey to members of the assembled committee querying their knowledge of the availability of airway management devices. The dataset was gathered from 14 airway management leaders identified across 4 surgical facilities, 6 emergency departments and 5 medical intensive care units at 8 hospitals and hospital campuses within the Yale New Haven Health system. Equipment available in greater than 75 % of locations included hyperangulated and standard geometry videolaryngoscopes, rigid tracheal tube stylets, tracheal tube introducers, flexible intubation scopes, scalpels and waveform capnography. Equipment available in 25 % to <75 % of locations included emergency invasive airway kits, wheeled airway towers or airway boxes, intubating oral airways, airway exchange and Aintree catheters, intubation-capable supraglottic airways, and awake intubation supplies. Glidescope (Verathon) was the most common videolaryngoscope and flexible intubation scope, and Aura (Teleflex) was the most common intubation-capable supraglottic airway available. The initiative illustrated the feasibility and utility of developing a committee of airway leaders in a large health system. While all locations had access to a requisite array of airway management devices, there was variation in the availability and brand of individual airway equipment.

Spin-Tunneling Magnetoresistive Effects in Bottom-Up-Grown Ni/Graphene/Ni Nanojunctions.

Two-dimensional (2D) materials embedded in magnetic tunnel junctions (MTJs) provide a platform to increase the control over spin transport properties by the proximity spin-filtering effect. This could be harnessed to craft spintronic devices with low power consumption and high performance. We explore the spin transport in the 2D MTJs based on graphene, which is uniformly grown on Ni(111) substrates using the chemical vapor deposition technique. After the Ni thin film is deposited bottom-up on the well-grown Ni(111)/graphene surface in an e-beam evaporation system by the physical vapor deposition method, the Ni/graphene/Ni nanojunction array devices are successfully prepared by using nanography technology. Evidence of the emergence of tunneling magnetoresistance (TMR) effects with ultrasmall resistance × area products in graphene-based nanojunctions is observed by the exclusion of anisotropic magnetoresistance. The theoretical analysis shows that this TMR is mainly attributed to the strong spin-filtering effect at the perfect Ni(111)/graphene interface. Besides, earlier findings indicate that the TMR would be promoted more effectively if the short-circuit effect formed in the process of nanographic etching by an ion beam can be further eliminated. Overall, this study provides a path to harness the full potential of graphene-based MTJ array devices with a high efficiency and performance.

Six-Letter DNA Nanotechnology: Incorporation of Z-P Base Pairs into Self-Assembling 3D Crystals.

Artificially expanded genetic information systems (AEGIS) were developed to expand the diversity and functionality of biological systems. Recent experiments have shown that these expanded DNA molecular systems are robust platforms for information storage and retrieval as well as useful for basic biotechnologies. In tandem, nucleic acid nanotechnology has seen the use of information-based "semantomorphic" encoding to drive the self-assembly of a vast array of supramolecular devices. To establish the effectiveness of AEGIS toward nanotechnological applications, we investigated the ability of a six-letter alphabet composed of A:T, G:C and synthetic Z:P (Z, 6-amino-3-(1'-β-d-2'-deoxy ribofuranosyl)-5-nitro-(1H)-pyridin-2-one; P, 2-amino-8-(1'-β-d-2'-deoxyribofuranosyl)-imidazo-[1,2a]-1,3,5-triazin-(8H)-4-one) base pairs to engage in 3D self-assembly. We found that crystals could be programmably assembled from AEGIS oligomers. We conclude that unnatural base pairs can be used for the topological self-assembly of crystals. We anticipate the expansion of AEGIS-based nucleic acid nanotechnologies to enable the development of novel nanomaterials, high-fidelity signal cascades, and dynamic nanoscale devices.

Continuous monitoring of heart failure biomarker using a sensitive graphene-based electrical sensor

Abstract Heart Failure (HF) is a complex condition that imposes significant burdens on both patients and healthcare systems. The economic impact of HF therapy and management is substantial, underscoring the urgency for proactive measures to mitigate its development. Regular assessments play a pivotal role in identifying individuals at risk and initiating timely interventions to prevent or delay HF progression [1, 2]. NT-proBNP, an amine-terminated form of brain natriuretic peptide, emerges as a promising biomarker in the realm of chronic HF diagnosis, prognosis, and risk assessment [3]. Its utility lies in providing valuable insights into disease progression and prognosis. In recent years, biosensors based on Field Effect Transistors with Graphene (Gr) gate (GFET) have garnered attention for their rapid response, sensitivity, and on-chip integration [4]. Here, we present a sensitive miniaturized GFET sensor for continuous NT-proBNP measurement. The sensor is an array of GFET devices with sensing gates of a monolayer Gr decorated with aptamers as catch probes. Averaging over similar devices in an array approach ensures measurement consistency throughout the experiment. Moreover, the significant challenge posed by the Debye length in FET biosensors is effectively addressed through the functionalization with short folding aptamers [4]. The sensor is built based on a chip comprising an array of 28 individual micro GFETs (Fig. 1a). For the functionalization of Gr gates, we utilized 1-pyrene butyric acid N-hydroxysuccinimide ester as a linker between the aptamer probes and the Gr surface. Subsequently, the Gr surface was incubated with an amine-terminated aptamer solution (Fig. 1c). A schematic diagram of the sensory chip having a droplet of the sample is shown in Fig. 1b. To quantify NT-proBNP levels an 8µL droplet of the buffer solution containing a specific NT-proBNP concentration was deposited onto the sensor. The drain current (IDS) served as the sensor signal for each target concentration (Figs. 2a and 2b). The sensor signal decreased with increasing target concentration, while negligible response was observed when injecting blank buffers. This phenomenon can be attributed to the folding of aptamers upon binding to their target. Also, continuous measurement was conducted at a fixed gate voltage of 0.9V, recording the drain current while the target concentration gradually increased in the sample droplet. This process revealed a decrease in sensor current as we expected (Fig. 2c). The sensor exhibits remarkably low detection limits of 50 pg/mL and a linear range from 100 pg/mL to 10 ng/mL, which are highly conducive for early HF diagnosis and aligning well with reported NT-proBNP levels in patient biofluid [5]. The proposed sensor holds promise as a wearable device for continuous monitoring of high-risk patients. Additionally, this technology shows potential as a detection tool for acute heart failure in hospitalized patients.Sensor viewSensor responses

Scalable fabrication of vertically arranged Bi2Se3 crossbar arrays for memristive device applications

Despite the unique advantages of the memristive switching devices based on two-dimensional (2D) transition metal dichalcogenides, scalable growth technologies of such 2D materials and wafer-level fabrication remain challenging. In this work, we present the gold-assisted large-area physical vapor deposition (PVD) growth of Bi2Se3 features for the scalable fabrication of 2D-material-based crossbar arrays of memristor devices. This work indicates that gold layers, prepatterned by photolithography processes, can catalyze PVD growth of few-layer Bi2Se3 with 100-folds larger crystal grain size in comparison with that grown on bare Si/SiO2 substrates. We also present a fluid-guided growth strategy to improve growth selectivity of Bi2Se3 on Au layers. Through the experimental and computational analyses, we identify two key processing parameters, i.e., the distance between Bi2Se3 powder and the target substrate and the distance between the leading edges of the substrate and the substrate holder with a hollow interior, which plays a critical role in realizing large-scale growth. By optimizing these growth parameters, we have successfully demonstrated cm-scale highly-selective Bi2Se3 growth on crossbar-arrayed structures with an in-lab yield of 86%. The whole process is etch- and plasma-free, substantially minimizing the damage to the crystal structure and also preventing the formation of rough 2D-material surfaces. Furthermore, we also preliminarily demonstrated memristive devices, which exhibit reproducible resistance switching characteristics (over 50 cycles) and a retention time of up to 106 s. This work provides a useful guideline for the scalable fabrication of vertically arranged crossbar arrays of 2D-material-based memristive devices, which is critical to the implementation of such devices for practical neuromorphic applications.

Intralayer/Interlayer Codoping Stabilizes Polarity Modulation in 2D Semiconductors for Scalable Electronics.

2D semiconductors show promise as a competitive candidate for developing future integrated circuits due to their immunity to short-channel effects and high carrier mobility at atomic layer thicknesses. The inherent defects and Fermi level pinning effect lead to n-type transport characteristics in most 2D semiconductors, while unstable and unsustainable p-type doping by various strategies hinders their application in many areas, such as complementary metal-oxide-semiconductor (CMOS) devices. In this study, an intralayer/interlayer codoping strategy is introduced that stabilizes p-type doping in 2D semiconductors. By incorporating oppositely charged ions (F and Li) with the intralayer/interlayer of 2D semiconductors, remarkable p-type doping in WSe2 and MoTe2 with air stability up to 9 months is achieved. Notably, the hole mobility presents a 100-fold enhancement (0.7 to 92 cm2 V-1 s-1) with the codoping procedure. Structural and elemental characterizations, combined with theoretical calculations validate the codoping mechanism. Moreover, a CMOS inverter and more complex logic functions such as NOR and XNOR, as well as large-area device arrays are demonstrated to showcase its applications and scalability. These findings suggest that stable and straightforward intralayer/interlayer codoping strategy with charge-space synergy holds the key to unlocking the potential of 2D semiconductors in complex and scalable device applications.

Tailored Environment-Friendly Reverse Type-I Colloidal Quantum Dots for a Near-Infrared Optical Synapse and Artificial Vision System.

Colloidal quantum dots (QDs) are emerging as potential candidates for constructing near-infrared (NIR) photodetectors (PDs) and artificial optoelectronic synapses due to solution processability and a tunable bandgap. However, most of the current NIR QDs-optoelectronic devices are still fabricated using QDs with incorporated harmful heavy metals of lead (Pb) and mercury (Hg), showing potential health and environment risks. In this work, we tailored eco-friendly reverse type-I ZnSe/InP QDs by copper (Cu) doping and extended the photoresponse from the visible to NIR region. Transient absorption spectroscopy analysis revealed the presence of Cu dopant states in ZnSe/InP:Cu QDs that facilitated the extraction of photogenerated charge carriers, leading to an enhanced photodetection performance. Specifically, under 400 nm illumination, the Cu-doped ZnSe/InP QDs-based PDs presented a broadband photodetection ranging from ultraviolet (UV) to NIR, with a responsivity of 70.5 A W-1 and detectivity of 2.8 × 1011 Jones, surpassing those of the undoped ZnSe/InP QDs-based PDs (49.4 A W-1 and 1.9 × 1011 Jones, respectively). More importantly, the ZnSe/InP:Cu QDs-PDs demonstrated various synapse-like characteristics of short-term plasticity (STP), long-term plasticity (LTP), and learning-forging-relearning under NIR light illumination, which were further used to construct PD array devices for simulating the artificial visual system that is available in prospective optical neuromorphic applications.

Key Imaging Factors for Transcatheter Management of Tricuspid Regurgitation: Device and Patient Selection

The growing awareness of tricuspid regurgitation (TR) and the fast-expanding array of devices aiming to percutaneously repair or replace the tricuspid valve have underscored the central role of multi-modality imaging in comprehensively assessing the anatomical and functional characteristics of TR. Accurate phenotyping of TR, the right heart, and pulmonary vasculature via echocardiography, computed tomography, and, occasionally, cardiovascular magnetic resonance and right heart catheterization is deemed crucial in choosing the most suitable treatment strategy for each patient and achieving procedural success. In the first part of the present review, key imaging factors for patient selection will be discussed. In the ensuing sections, an overview of the most commonly used, commercially available systems for transcatheter repair/replacement will be presented, along with their respective selection criteria and information on intraprocedural imaging guidance; these are edge-to-edge repair, orthotopic and heterotopic replacement, and valve-in-valve procedures.

Safety of Magnetic Resonance Imaging in Patients with Cardiac Implantable Electronic Devices.

MRI (magnetic resonance imaging) represents the diagnostic image modality of choice in several conditions. With an increasing number of patients requiring MRI for diagnostic purposes, the issue of safety in patients with cardiac implantable electronic devices (CIED) undergoing this imaging modality will play an ever more important role. The purpose of this study was to assess the safety and device function following MRI in an unrestricted real-world cohort of patients with a wide array of cardiac devices. We conducted a retrospective single-center study including 1010 MRI studies conducted in adult patients (≥18 years) with an implanted CIED treated in the University Hospital of Munich (LMU) between July 2012 and March 2024. Patients with non-MR conditionally labeled leads, abandoned or epicardial leads, as well as lead fragments, were included for analysis. Across a total of 1010 MRIs (920 total MR-conditional device generators) performed in patients with an implanted CIED, there were no deaths, reports of discomfort, palpitations, heating, or ventricular arrythmias in the 24 h following MRI. Only 2/1010 MRIs were followed by a reported atrial arrhythmia within 24 h, both in patients with an MR-conditional pacemaker (PM) device without an abandoned lead. No significant changes in device function following MRI from baseline were observed across all included CIEDs. Lastly, no instances of severe malfunction, such as generator failure, loss of capture, electrical reset, or inappropriate inhibition of pacing, were found in post-MRI interrogation reports across all MRI studies. Based on the analysis of 1010 MRIs undergone by patients with CIEDs, following standardized device interrogation, manufacturer-advised device programming, monitoring of vital function, and manufacturer-advised reprogramming, MRI can be performed safely and without adverse events or changes in device function.

All-In-One Optoelectronic Transistors for Bio-Inspired Visual System.

Visual perception has profound effects on human decision-making and emotional responses. Replicating the functions of the human visual system through device development has been a constant pursuit in recent years. However, to fully simulate the various functions of the human visual system, it is often necessary to integrate multiple devices with different functions, resulting in complex, large-volume device structures and increased power consumption. Here, an optoelectronic transistor with comprehensive visual functions is introduced. By coupling diverse photoreceptive properties of the channel and electrical regulation through charge injection/ferroelectric switching from the hafnium-based gate, the devices can simulate functions of both photoreceptors in the retina and synapses in the visual cortex. A device array is constructed to confirm the perceptual functions of cone and rod cells. Subsequently, color discrimination and recognition for color images are achieved by combining the tunable perception and synapse functions. Then an intelligent traffic judgment system with this all-in-one device is developed, which is capable of making judgments and decisions regarding traffic signals and pedestrian movements. This work provides a potential solution for developing compact and efficient devices for the next-generation bio-inspired visual system.

Wafer-Sized CsPbBr3/CsPbCl3 Heterojunction: Breaking the Trade-Off between Sensitivity and Dark Current for Efficient X-ray Detector.

Polycrystalline lead halide perovskite finds promising use in fabricating X-ray detectors with a large lateral size, adjustable thickness, and diverse synthesis processes. However, a large dark current hinders its development for weak signal detection. Herein, we propose a multistep pressing strategy for manufacturing a CsPbBr3/CsPbCl3 heterojunction wafer for a reduced dark current X-ray detector, and the device keeps a high sensitivity value after the insertion of a barrier by heterojunction; thus, the trade-off between sensitivity and dark current can be broken. The X-ray detector with a metal-semiconductor-metal structure yields a sensitivity of 6.32 × 104 μC Gyair-1 cm-2 at a bias of 12 V, a 1/f noise of 1.02 × 10-13 A/Hz-1/2, and a detection limit of 66.58 nGy s-1. These performance parameters are considerably better than those of a similar X-ray detector based on the single-structure wafer. The improved device performance of the heterostructure X-ray detector is ascribed to the suppressed carrier recombination, enhanced carrier transportation of the heterojunction, and strong X-ray attenuation of the CsPbCl3 layer. The pixel array device is further used in imaging applications. Hence, this study provides an efficient strategy for fabricating heterostructure polycrystalline lead halide perovskite wafers for use in high-performance wafer-based X-ray detectors.

Influences of VR technology on the effect of museum narrative based on embodied cognitive theory: a case study of the opium war museum

Purpose With an increasing array of new technologies and devices emerging as novel approaches to museum narratives, scholars are intrigued by the narrative effect they produce. Within this context, this study aims to conduct a quantitative case study on the influencing mechanisms among technology embodiment, technology attachment, museum narrative effect and perceived museum image based on embodied cognitive theory (ECT). Design/methodology/approach By introducing the Opium War Museum, Dongguan City, Guangdong Province, China, as an empirical case study, the authors collected data, through questionnaires, from 425 visitors who had experienced virtual reality (VR) technology in the museum. The data was then analyzed by using the maximum likelihood estimate for structural equation modeling. Findings Technology embodiment and technology attachment have significant positive correlations with the museum narrative effect. Technology attachment provides a partial mediating effect between technology embodiment and the museum narrative effect. The perceived museum image moderates such mediating effects of technology attachment. Originality/value This study brings the emerging idea of developing visitor experiences with VR through expanding the applications of ECT in the museum scenario. First, the authors identified the underlying interaction patterns between various factors that influence the museum narrative effect. Second, the authors verified that technology can optimize the museum narrative effect and help the creative transformation of cultural relics and culture. This study also provides practical recommendations to improve the technological service experience and strengthen the “audience-centric” management concept of museums

Integrated mid-infrared sensing and ultrashort lasers based on wafer-level Td-WTe2 Weyl semimetal

There is an urgent need for infrared (IR) detection systems with high-level miniaturization and room-temperature operation capability. The rising star of two-dimensional (2D) semimetals with extraordinary optoelectronic properties can fulfill these criteria. However, the formidable challenges with regard to large-scale patterning and substrate-selective requirements limit material deposition options for device fabrication. Here, we report a convenient and straightforward eutectic-tellurization transformation method for the wafer-level synthesis of 2D type-II Weyl semimetal WTe2. The non-cryogenic WTe2/Si Schottky junction device displays an ultrawide detection range covering 10.6 μm with a high detectivity of ∼109 Jones in the mid-infrared (MIR) region and a short response time of 1.3 μs. The detection performance has surpassed most reported IR sensors. On top of that, on-chip device arrays based on Schottky junction display an outstanding MIR imaging capability without cryogenic cooling, and 2D WTe2 Weyl semimetal can serve as a saturable absorber for stable Q-switched and mode-locked laser operation applications. Our work offers a viable route for wafer-scale vdW preparation of 2D semimetals, showcasing their intriguing potential in on-chip integrated MIR detection systems and ultrafast laser photonics.

FPGA Implementation of Sliding Mode Control and Proportional-Integral-Derivative Controllers for a DC–DC Buck Converter

DC–DC buck converters have been designed by incorporating different control stages to drive the switches. Among the most commonly used controllers, the sliding mode control (SMC) and proportional-integral-derivative (PID) controller have shown advantages in accomplishing fast slew rate, reducing settling time and mitigating overshoot. The proposed work introduces the implementation of both SMC and PID controllers by using the field-programmable gate array (FPGA) device. The FPGA is chosen to exploit its main advantage for fast verification and prototyping of the controllers. In this manner, a DC–DC buck converter is emulated on an FPGA by applying an explicit multi-step numerical method. The SMC controller is synthesized into the FPGA by using a signum function, and the PID is synthesized by applying the difference quotient method to approximate the derivative action, and the second-order Adams–Bashforth method to approximate the integral action. The FPGA synthesis of the converter and controllers is performed by designing digital blocks using computer arithmetic of 32 and 64 bits, in fixed-point format. The experimental results are shown on an oscilloscope by using a digital-to-analog converter to observe the voltage regulation generated by the SMC and PID controllers on the DC–DC buck converter.