Nanofluidic ionic transistors typically require gate voltages above 1 V and operate only at submillimolar ionic strengths, limiting their biocompatible applications. We demonstrate ionic transistors consisting of single sub-10 nm nanopores drilled in van der Waals (vdW) heterostructures with internal gate electrodes made of few-layer graphene. These devices deliver up to 10-fold current modulation at gate voltages as low as 0.3 V in 10 mM KCl, and ∼2-fold modulation at near-physiological 100 mM KCl. Baseline conductance with no gate shows surface-charge-dominated transport below 100 mM KCl, consistent with negatively charged hBN walls and ∼5 nm opening of the pores. The surface charge and the electrochemical asymmetry introduced by the three-electrode configuration govern the device's behavior: negative gate voltage (VG) enriches ionic concentrations and enhances current, whereas positive VG induces a local depletion zone that suppresses transport. The current modulation by VG is dependent on the polarity of the transmembrane potential and leads to ion current rectification. Molecular dynamics simulations of a nanopore in a hBN-graphene-hBN stack reveal confinement and surface charge-dependent suppression of the relative permittivity of interfacial water. Continuum modeling with radially varying interfacial water permittivity reproduces the asymmetric I-V characteristics and explains how the embedded gate sculpts local potential and ion concentrations. By enabling sub-0.5 V control of ionic transport at up to 100 mM salt concentrations, these devices address a key need in nanofluidics to create low-power ionic circuits and biosensing.

A comprehensive first-principles investigation of tunable quantum transport in pyrrole-based molecular junctions is performed by using density functional theory combined with the nonequilibrium Green's function approach. When coupled to zigzag graphene nanoribbon electrodes, the pyrrole monomer/oligomer-based devices exhibit three essential transport characteristics, namely a pronounced negative differential resistance (NDR) effect, nonlinear gate-controlled modulation, and destructive quantum interference (DQI)-induced switching. The current amplitude decreases systematically with increasing oligomer length, while the peak-to-valley ratio increases, reaching a maximum of 17.36. Gate modulation effectively preserves and enhances the NDR effect, where a negative gate voltage shifts the HOMO toward the Fermi level, broadening the HOMO-dominated transmission peak and improving the stability of NDR. Furthermore, conformational rotations disrupt the π-conjugated pathway, inducing strong DQI that drastically suppresses conductance. This mechanism enables a robust molecular switching behavior, achieving an on/off ratio reaching as high as 6.48 × 103. These results establish clear structure-transport correlations and demonstrate the potential of pyrrole-based molecular junctions for highly tunable functional components in future molecular electronic devices.

An optimization method based on a dual negative voltage driving waveform is proposed to address the droplet jetting instability caused by residual oscillations in piezoelectric drop-on-demand (DOD) inkjet printing of ultralow viscosity photoresist (0.71 mPa·s). The experimental system for photoresist droplet ejection and observation is developed to systematically investigate the effect of driving waveform parameters on droplet generation. Experimental results demonstrate that the designed dual negative voltage driving waveform effectively suppresses residual oscillations and significantly improves the stability of photoresist droplet jetting by introducing a suppression negative voltage into the traditional drive waveform. Furthermore, by optimizing the timing parameters, the optimal duration and interval time of the suppression voltage are determined to be t3 = 2.4 μs and Δt2 = 4.1 μs, respectively, enabling uniform and stable photoresist droplet jetting from three-phase nozzles without satellite droplets. Moreover, the effects of printhead driving parameters on droplet characteristics are quantitatively explored. The optimal droplet diameter and ejection velocity are 23.20 μm and 9.51 m/s at the driving voltage and frequency of 6.3 V and 5 kHz, respectively. This work not only provides a feasible waveform design strategy for stable droplet jetting of ultralow viscosity photoresist but also lays a solid foundation for the application of inkjet technology in semiconductor wafer-level packaging.

We investigated the recently discovered extremely long-period stripe structure (ELPSS) in LaTe3using scanning tunneling microscopy (STM)/scanning tunneling spectroscopy. We found that the contrast of the ELPSS was inverted between STM images acquired at positive and negative setup bias voltages, and that the tunneling spectrum exhibited a spatial variation corresponding to the ELPSS. These results indicate that the ELPSS is a charge density wave (CDW) with an energy gap opening near the Fermi energy and suggest that the bilayer splitting induces the formation of this extremely long-period CDW.

In this work, the influences of the direct current blocking capacitor, stray capacitance, and stray resistance in the external circuit on the self-bias driven by tailored voltage waveform (TVW)-driven asymmetric capacitive discharges are investigated using a one-dimensional three-velocity particle-in-cell/Monte Carlo collision model coupled with an external circuit. Under a zero-initial-phase sinusoidal TVW drive with an amplitude ratio of 3:2:1, a dc self-bias voltage is generated and can be significantly modulated by the blocking capacitor, stray resistance, and stray capacitance. The approximate adjustment ranges of each external circuit parameter, as well as an optimized combination of circuit parameters under specific discharge conditions are presented. Based on bias control using a single external component, combined control of multiple external circuit parameters enables a wider tuning range of plasma density, ion flux, and ion energy at the boundary. In addition, the mechanisms responsible for the formation of positive and negative self-bias voltages at different pressures are discussed. These results may provide insight and a theoretical reference for the engineering design of bias control in electrical asymmetric capacitively coupled plasma systems.

We present a novel promising fabrication technique for Surface Dielectric Barrier Discharge (SDBD) plasma actuators based on Aerosol Jet Printing (AJP) technology of conductive inks on dielectric surfaces and characterize the AJP-SDBDs optical and electromechanical performance. Linear SDBD designs, with ultra-smooth electrode edges of micrometer thickness have been fabricated, which when driven by AC, High Voltage waveforms, present stable plasma operation and reproducible features. We measure the electromechanical characteristics in terms of ink-related electrical properties (through Van der Pauw-resistivity and Hall measurements), plasma properties through electrical diagnostics, time-resolved imaging and optical emission spectroscopy (OES), while we perform Particle Tracking Velocimetry (PTV) measurements of the induced wall-jet flow. The printed electrodes show a clear metallic behavior, with their electronic properties comparing very favorably to other printable materials. The AJP-SDBDs show similar electromechanical characteristics with conventional SDBDs fabricated via conventional methods, good robustness, and more intense nature indicating lower breakdown voltage requirements. The emission spectra from the discharge show dominant formation of excited N 2 and N 2 + species. Based on high-resolution OES, an estimation of rotational and vibrational temperatures of the N 2 (C) state is performed, showing the strong non-equilibrium nature of the discharges produced. This helps in maintaining the average gas temperature in the positive and negative AC voltage phase at low levels (below 350 K) indicating its minimal impact on the gas dynamics. In terms of induced flow and electrohydrodynamic (EHD) forcing, the AJP-SDBD resulted in wall-jet flows with a maximum velocity achieved of approximately 5 m/s and a wall-jet height of approximately 3 mm at 7 mm from the exposed electrode edge for the 30 kV 3 kHz case. At the same conditions, the EHD force reached more than 27.5 mN/m. The obtained values and trends are in good agreement with literature values of conventional AC driven SDBD actuators, showcasing AJP potential as a promising fabrication technique for robust and efficient plasma actuators and related applications. • First time application of Aerosol Jet Printing (AJP) technology in the fabrication of Surface Dielectric Barrier Discharge (SDBD) plasma actuators. • Silver ink electrodes present perfect alignment, great adhesion, ultra-fine and ultra-smooth edges, micrometer thickness and low resistivity. • Optical and electromechanical characterization show similar characteristics with SDBDs fabricated via conventional methods, good robustness, and enhanced discharge ignition and intensity characteristics. • Measured maximum induced flow velocities of about 5 m/s and total EHD body force more than 27.5 mN/m. • AJP-SDBDs show great promise as a fabrication technique for next generation of robust, efficient and novel plasma actuators.

The growing demand for fast and energy-efficient computing has motivated the development of neuromorphic hardware inspired by biological neural systems. Spiking neural networks (SNNs), as the third generation of neural networks, offer an event-driven and highly parallel computing paradigm that is well suited for such applications. A key challenge in hardware SNNs is the efficient implementation of synaptic learning mechanisms, particularly spike-timing-dependent plasticity (STDP), with minimal circuit complexity and energy overhead. In this work, we propose a fully CMOS leaky integrate-and-fire (LIF) neuron designed to enable local, on-chip STDP-like learning when interfaced with analog memristive synapses. The proposed neuron generates a bipolar output spike composed of both positive and negative voltage pulses, allowing direct modulation of memristor conductance without the need for complex peripheral circuits or explicit timing storage elements. The neuron operates in two distinct modes of training mode, which produces bipolar spikes to support synaptic updates, and inference mode, which generates a single unipolar spike while deactivating non-essential circuitry to reduce power consumption. To validate the proposed design, a proof-of-concept 15×4 spiking neural network incorporating a winner-takes-all (WTA) mechanism is implemented in 65-nm CMOS technology and evaluated using circuit-level simulations. The results demonstrate correct local synaptic adaptation, stable neuron operation under process variations, and successful pattern association during training and inference. The network processes each training pattern within 0.6 ms and performs inference within 0.32 ms.

Two-dimensional (2D) heterostructures with outstanding frictional properties have sparked immense interest in the field of tribology. Here, graphene oxide (GO)-coated conductive probes were fabricated, and the frictional behavior of the GO/graphene heterointerface under varying bias voltages was investigated using conductive atomic force microscopy. The friction at the GO/graphene interface increases with applied bias, enabling real-time and reversible control within a low-bias regime. Owing to the dielectric property of GO and the electrical conductivity of graphene, charges accumulate at the interface. Because atomically thin thickness of 2D materials, the accumulated charges produce a large interfacial electrostatic force for stable friction control. However, the stability of this control decreases when high positive bias is applied. Scanning Kelvin probe microscopy and adhesion measurements indicate that strong electric fields enable a fraction of the accumulated electrons to tunnel through the GO barrier, thereby altering the interfacial electrostatic interactions. In contrast, high negative bias voltages induce electrochemical oxidation of graphene to varying extents, resulting in a permanent and substantial friction modulation. These findings advance the fundamental understanding of friction in 2D heterointerfaces and provide important insights for friction regulation and the development of electrically tunable smart tribological systems.

Recent advancements in AI and ML algorithms demand high-density and low-power devices. The Tunnel Field-Effect Transistor (TFET) presents a viable strategy for digital systems with reduced power consumption. The overall performance of digital circuits that use TFETs is deteriorated by the substantial P-I-N forward leakage currents that these devices encounter when exposed to large negative drain-to-source voltages. Therefore, using 2-D simulations, we discuss in detail the nature of P-I-N forward leakage current dependency on the negative drain voltages. In addition, we have analyzed how basic device design parameters affect the P-I-N forward leakage current. Furthermore, a novel TFET structure having an additional electrode has been proposed to mitigate the P-I-N forward leakage current. The suggested architecture is an attractive substitute for conventional TFETs since it substantially decreases ambipolar current by three orders of magnitude and forward leakage current by ten orders of magnitude.

Active control of thermal emission is increasingly important for applications in thermal management, infrared sensing, and energy conversion. While various approaches have been taken to achieve dynamic change of emissivity, electrical tuning in particular holds great promise for the benefits of analog control and programming. In this work, we propose a voltage-gated metal–oxide–semiconductor (MOS) nanowire device for achieving active tunable spectral-directional emittance within an analog voltage range. With negative voltages from 0 to −8.5 V, numerical simulation shows the non-uniform carrier concentration depleted within most of the nanometric semiconductor layer. By considering the semiconductor layer as a gradient index medium upon depletion at a given gating voltage, full-wave optical simulation demonstrates a spectral emittance peak whose amplitude and wavelength can be tuned from 0.80 at 8 μm to 0.40 at 13 μm for transverse-magnetic polarized waves at a 45° emission angle. The underlying mechanism is elucidated as the Berreman mode associated with the near-zero effective dielectric function of the extraordinary component of the nanowire structures, which changes significantly with depleted carrier concentration upon gating. In comparison, the planar MOS counterpart device does not show any tunable infrared emittance as the penetration depth of the semiconductor thin film is much larger than the nanometric depletion length.

The modern power network is composed of a huge number of transmission lines and generators. The synchronous generator modelling and its stability analysis are crucial in a power system network. The single machine is analyzed with Phillips Heffron or K1 to K6 model, usually all constants are positive in the general case. In a few cases, the constants K4 and K5 are negative; for high values of external system reactance and high generator outputs, K5 becomes negative. With a negative K5 value automatic voltage regulator action introduces a positive synchronizing torque and negative damping torque. The classical system usually has a positive K4 value; as long as it is positive, it introduces positive damping torque. In some special situations, it can become negative; hence, this article aims to show that typical power systems lead to negative K4 values and their effects on system small-signal stability. The two typical power systems lead to negative K4 values being realized and modeled for stability study in this article, and the improvement of small signal stability is achieved with the design and implementation of a PID controller and power system stabilizer. Finally, comparison is performed without any controller, with a PID controller, and with power system stabilizers on small signal stability; the results prove the effectiveness of the PSS on SSS improvement.

We report the dielectric and magnetic properties of epitaxial thin films of the high entropy oxide (HEO) perovskite Nd(Cr0.2Mn0.2Fe0.2Co0.2Ni0.2)O3, which orders magnetically below Tmag≈190 K. At T ≫ Tmag, the dielectric response reveals a Debye-type frequency dependence with a zero-frequency dielectric constant of ≈230-250. The dc bias voltage loops of are reversible but exhibit three distinct peaks centred at zero and finite positive and negative voltage. We provide evidence that the zero-bias peak is governed by the oxygen sublattice while the finite bias peaks originate from cationic dipoles. The maximal response of the latter appears to be shifted to finite bias by a static uncompensated electric field due to a vertical gradient of the oxygen content. Below Tmag, this anomalous dielectric response is strongly suppressed, presumably by magnetostriction that counteracts and freezes the ionic displacements. These findings indicate a unique correlation between configurational entropy, dielectric response, and magnetic properties. In combination with a large dielectric strength, it enables a non-hysteretic tuning of the dielectric response of magnetoelectronic devices with multiple parameters like temperature, electric, and magnetic field. This HEO is equally interesting for fundamental studies of competing electric and magnetic orders in strongly disordered materials.

This paper will investigate influencing factors (gate voltage, switch on time etc.) on the dynamic behaviour of the source-drain voltage characteristic (V SD ) of SiC-MOSFETs. V SD is a critical parameter needed for temperature read-out during the power cycling or other reliability test via the V SD (T) method. 1200 V SiC MOSFETs from ten different manufacturers as well as chip generations with approximately same R DSON of 80 mΩ were used in this work. If the off-gate voltage is not sufficiently negative during temperature read-out, a “run-in” behaviour of the forward voltage of the body diode up to a static value occurs for every manufacturer. This should be avoided when determining the temperature of the chip. Otherwise, large errors in temperature detection are likely and possible gate under- and overshoots due to high parasitic gate loops of a power cycling test benches have stronger impact on the transient response of the V SD . Therefore, a sufficiently negative gate voltage should be applied to close the n-channel completely – in some cases even below the allowed datasheet value. Further, it has been confirmed that some manufacturers still face a transient V SD response, although the gate voltage is already very negative, which could make the temperature read-out quite complicated. Furthermore, a small load current (∼1 A for example) has no influence depending on the test mode (MOSFET/3rd Quadrant) on the V SD -response. • Chip technology (SiO 2 /SiC interface defect rate, …) + power cycling test setup (e.g. L G , R G,off , …) defines dynamic V SD behaviour • If the n-channel is completely closed the V SD -value for the planar and asymmetric trench structure is directly stable • For the newer double trench structures further longer lasting dynamic V SD effects were found, although the n-channel is closed • Run gate pulse pattern w/o small load current (∼1A) to detect any temperature readout errors; Compare T C and T vj before start

ABSTRACT This study employed a Langmuir probe to investigate charged particle production characteristics in a cesium‐free aluminum plasma grid (Al‐PG) system, wherein different electric voltage differences were applied across the control grid (CG), extraction grid (EX), and analyzer limiter plate (ALP). The probe enabled measurements of current at various spatial positions and bias voltages, providing direct insight into the behavior of electrons and ions under different electrode voltage conditions. The probe current results indicate that, when comparing different CG voltages, the probe current at V (positive ion extraction) is significantly larger than that at V (negative ion extraction). Probe measurements revealed that, when the ALP voltage is varied below the probe voltage, the probe current initially increases and subsequently decreases. Under the same conditions, the probe current gradually decreases with increasing EX voltage. When a negative voltage is applied to the probe, the floating potential corresponds to the probe current peak, and this peak shifts progressively with increasing EX voltage. These probe‐based observations clarify the influence of electrode potentials on charged particle transport and provide experimental guidance for optimizing cesium‐free negative ion sources for advanced plasma applications.

In this work, the experimental results of the electrical discharge and output ion beam characteristics of the cold conical cathode ion source at different pressures are measured using nitrogen and argon gases. The optimum distance between the disc anode and the conical cathode, as well as the optimum inner diameters of two insulator confinement rings, are determined at different pressures using nitrogen gas. Also, the optimum distance between the ion exit aperture of the conical cathode and the ion collector plate is determined at a constant pressure and different discharge currents using nitrogen and argon gases. The ion source optimum efficiency at optimum operating conditions, constant pressure and discharge current is determined using nitrogen and argon gases. Also, the effect of negative voltage applied to the ion collector plate on the extracted ion beam current at optimum operating conditions and constant pressure is measured using nitrogen and argon gases. Additionally, the changes in optical properties of Makrofol nuclear track detector samples after exposure to different ion fluence from 5 × 1016 ions / cm2 up to 5 × 1018 ions / cm2 are determined using argon ions. The transmission of these samples in the wavelength range 200–2500 nm is measured. In addition, the color intensity, ΔE (the color difference between the non-exposure Makrofol sample and samples exposed to different argon ion fluence), is calculated. The color intensity increased with increasing argon ion fluence, indicating a significant color difference.

Inspired by the gating behavior of biological ion channels, microchannel-based sensing has emerged as an effective strategy for regulating ionic transport through charge density and pore size modulation. Field-effect transistor (FET)-based biosensors have received considerable attention owing to their high sensitivity to subtle charge variations. In this study, this character had been coupled with the junction field-effect transistor (JFET) detection technique to develop a sensitive biosensor for glutathione (GSH). A hydrogel was formed by Schiff-base crosslinking between aldehyde-modified hyaluronic acid (AHA) and 3-[(3-hydrazinyl-3-oxopropyl)disulfanyl] propanehydrazide (DTP) and subsequently confined within the microchannel, which served as a tunable resistor positioned between the gate and source of the JFET. Variations in the microchannel resistance induce a voltage division effect, thereby modulating the distribution of the effective gate voltage, which changes the channel current. Upon the presence of GSH, disulfide bonds of DTP within the hydrogel were reduced, generating thiol groups and disrupting the hydrogel network, which enlarged the pore size and increased the negative charge density. These changes reduced the microchannel resistance and increased the effective negative gate voltage, leading to a significant reduction of the channel current. The biosensor exhibited excellent sensitivity and selectivity toward GSH with a linear range from 100 nM to 1.00 mM, and the detection limit was 38.1 nM, along with good recovery and reproducibility in diluted human serum samples. This sensor provides a novel strategy for highly sensitive GSH detection and holds potential as a versatile platform for clinical diagnostics and disease monitoring.

Persistent photocurrent is widely observed in van der Waals (vdW) heterostructures and is often attributed to trap-assisted photogating, yet its microscopic origin remains unclear. Here, we clarify the mechanism in a gate-tunable MoS2/black phosphorus (BP) p-n heterojunction by combining DC and lock-in measurements with time-resolved decay. We simultaneously measure the general photocurrent (DC difference between illuminated and dark currents) and the net photocurrent extracted by the lock-in detection of a modulated laser. The net photocurrent is small and short-lived, whereas the DC photocurrent shows decay lifetimes (τ) exceeding hundreds of seconds at negative back-gate voltage (Vg) but collapses rapidly for positive Vg or under reverse bias. This τ-Vg and bias dependence is incompatible with a purely trap-dominated picture. We show that the long-lived response is dominated by majority-carrier recombination-induced self-heating in the forward-biased p-n junction, which drives thermoelectric and bolometric currents. By tuning the heterostructure between a p-n and an n-n configuration, the back gate effectively switches this thermal channel on and off. Using the experimentally extracted τ(Vg) in a leaky integrate-and-fire model, we further demonstrate an in-sensor spiking neural network with 91.95% accuracy on MNIST, highlighting the potential of thermally engineered persistent-photocurrent devices for neuromorphic vision.

Abstract The depth-resolved spatial distribution of trapped charges in silicon nitride (SiN) was directly visualized using operando voltage-applied angle-resolved hard X-ray photoelectron spectroscopy (AR-HAXPES) on metal–nitride–oxide–semiconductor (MNOS) structures. Analysis of voltage- and angle-dependent Si 1s binding-energy shifts reveals that, in the as-deposited state, hole traps are distributed throughout the SiN bulk, accounting for the negative flat-band voltage shift observed in capacitance–voltage (C–V) measurements. Under an accumulation bias, hole trapping is found to localize predominantly near the metal/SiN interface, while electrons accumulate near the SiN/SiO2 interface, producing oppositely directed potential gradients. This experimentally demonstrated spatial separation of trapped charges provides a direct physical origin of flat-band voltage shifts and establishes operando AR-HAXPES as a powerful tool for probing charge trapping in buried dielectric layers of advanced memory devices.

Introduction: A flexible traction substation provides power to the trains and the communication and signal facilities at the same time, taking into account the scarcity of strong power sources in the weak power grids. However, the severe impact of single-phase traction loads gives rise to negative sequence (NS) and voltage sag (VS) problems, which compromise the safe operation of electrical equipment. Methodology: To address these issues, this paper proposes a flexible traction power supply topology that integrates a power flow controller, a quasi-Z-source inverter, a dynamic voltage restorer, and photovoltaic (PV) cells, together with a comprehensive compensation strategy for NS and VS based on power quality standards. Results: The strategy employs the three-phase voltage unbalance factor (VUF) as a constraint and quantifies the influence of NS on VS detection accuracy, thereby achieving optimal NS compensation and in-phase VS compensation. Discussion: Hardware-in-loop (HIL) experiments confirm that the proposed structure and strategy reduce compensation power demand, maintain the VUF within 2%, and stabilize the grid voltage at 1 p.u. by providing active power support via the PV system, thereby reducing the capacity requirement of the primary compensation devices. Conclusion: These results demonstrate the capability of the integrated system to mitigate the impacts of single-phase traction loads and enhance power quality in weak grids.

The development of new n-type semiconductors is crucial for the further advancement of electronic and optoelectronic devices. Steamed buns, anciently known as "man tou", mainly made of wheat flour and are one of the staple foods for Chinese people. After being subjected to high-temperature treatment, the steamed buns transformed into carbonized steamed buns (CSB) with porous nanostructures, which exhibit a Hall mobility of up to 1.62 cm2/(V·s), far greater than C60(1.5 × 10−3−2.5 × 10−2 cm2/(V·s)), PCBM (2.0 × 10−7 cm2/(V·s)) and many polymer semiconductors (~10−6−10−2 cm2/(V·s)). A CSB-based bulk heterojunction memristor with a configuration of ITO/the CSB: PVK blends/Al is successfully fabricated. The device shows outstanding history dependent memristive switching performance, with 35 distinguishable conductance states, at a small sweep voltage range of ±1 V. An achieved production yield reaches up to 89%. Upon being subjected to consecutive positive or negative voltage sweeps, the current flowing through the device can be modulated continuously. When the 15 consecutive pulse voltages (pulse amplitude: 0.1 V; pulse width:10 μs, pulse period: 20 μs) were applied to the device, the observed total power consumption was about 7.63 nJ, suggesting a potential in low-energy neuromorphic computing applications. As expected, both the CSB and PVK do not exhibit any memristive effect under the same experimental condition. Utilizing the characteristic that the device can linearly adjust the weights, a simple convolutional neural network for traffic sign recognition was successfully constructed. After 300 rounds of training, the achieved recognition accuracy rate reached 88.77%. This work not only provides a new approach for developing low-cost and readily available organic semiconductors with high Hall mobility, but also offers a new idea for the subsequent development of high-performance artificial synapses and optoelectronic devices using carbonized steamed buns.