Search

Non-equilibrium Green's function (NEGF) and density functional theory (DFT) calculations are used to explore the impact of doping on the electron transport properties in a single tetracene molecule linked to gold electrodes using isocyanide anchoring groups. Boron (B) and Nitrogen (N) atoms are used for doping and co-doping (BN) of the carbon atoms placed at the edge of the tetracene molecule. It was found that the chemical doping of tetracene molecules mainly impacts the rectification trends compared to non-doped molecules. Our findings indicate that B doping significantly improves the rectification ratio compared to other dopants because of a greater difference between the current values under positive and negative biases as a result of asymmetric I-V characteristics. These inferences have also been assessed in terms of MPSH and transmission spectra. In addition, novel characteristic of negative differential resistance (NDR) is attained in single dopant molecular junctions. [ABSTRACT FROM AUTHOR]

Developing emerging technologies in Internet of Things and artificial intelligence requires high-speed, low-power, high-sensitivity, and switchable-functionality strain sensors capable of sensing subtle mechanical stimuli in complex ambience. Resonant tunneling diodes (RTDs) are the good candidate for such sensing applications due to the ultrafast transport process, lower tunneling current, and negative differential resistance. However, notably enhancing sensing sensitivity remains one of the greatest challenges for RTD-related strain sensors. Here, we use piezotronic effect to improve sensing performance of strain sensors in double-barrier ZnO nanowire RTDs. This strain sensor not only possesses an ultrahigh gauge factor (GF) 390 GPa−1, two orders of magnitude higher than these reported RTD-based strain sensors, but also can switch the sensitivity with a GF ratio of 160 by adjusting bias voltage in a small range of 0.2 V. By employing Landauer–Büttiker quantum transport theory, we uncover two primary factors governing piezotronic modulation of resonant tunneling transport, i.e., the strain-mediated polarization field for manipulation of quantized subband levels, and the interfacial polarization charges for adjustment of space charge region. These two mechanisms enable strain to induce the negative differential resistance, amplify the peak-valley current ratio, and diminish the resonant bias voltage. These performances can be engineered by the regulation of bias voltage, temperature, and device architectures. Moreover, a strain sensor capable of electrically switching sensing performance within sensitive and insensitive regimes is proposed. This study not only offers a deep insight into piezotronic modulation of resonant tunneling physics, but also advances the RTD towards highly sensitive and multifunctional sensor applications. [ABSTRACT FROM AUTHOR]

Nanofluidic devices have turned out to be exemplary systems for investigating fluidic transport properties in a highly restricted area, where the electrostatic interactions or chemical reactions between nanochannel and flowing species strongly dominate the ions and flow transport. Numerous nanofluidic devices have recently been explored to manipulate ion currents and construct electronic devices. Enlightened by electronic field effect transistors, utilizing the electric field effect of nanopore nanochannels has also been adopted to develop versatile nanofluidic devices. Here, we report a nanopore-based nanofluidic unijunction transistor composed of a conical glass nanopipette with the biomaterial polydopamine (PDA) coated at its outer surface. The asfabricated nanofluidic device exhibited negative differential resistance (NDR) and ion current oscillation (ICO) in ionic transport. The pre-doped copper ions in the PDA moved toward the tip as increasing the potential, having a robust shielding effect on the charge of the tip, thus affecting the surface charge density of the nanopore in the working zone. Finite element simulation based on a continuum model coupled with Stokes-Brinkman and Poisson-Nernst-Planck (PNP) equations revealed that the fluctuations in charge density remarkably affect the transport of ionic current in the nanofluidic device. The as-prepared nanofluidic semiconductor device was a ready-to-use equipment that required no additional external conditions. Our work provides a versatile and convenient way to construct nanofluidic electronic components; we believe by taking advantage of advanced surface modification methods, the oscillation frequency of the unijunction transistors could be controlled on demand, and more nanofluidic devices with resourceful functions would be exploited. [ABSTRACT FROM AUTHOR]

Computing‐in‐memory (CIM) architecture inspired by the hierarchy of human brain is proposed to resolve the von Neumann bottleneck and boost acceleration of artificial intelligence. Whereas remarkable progress has been achieved for CIM, making further improvements in CIM performance is becoming increasingly challenging, which is mainly caused by the disparity between rapid evolution of synaptic arrays and relatively slow progress in building efficient neuronal devices. Specifically, dedicated efforts are required toward developments of more advanced activation units in terms of both optimized algorithms and innovative hardware implementations. Here a novel bio‐inspired dendrite function‐like neuron based on negative‐differential‐resistance (NDR) behavior is reported and experimentally demonstrates this design as a more efficient neuron. By integrating electrochemical random‐access memory (ECRAM) with ionic regulation, the tunable NDR neuron can be trained to enhance neural network performances. Furthermore, based on a high‐density RRAM chip, fully hardware implementation of CIM is experimentally demonstrated by integrating NDR neuron devices with only a 1.03% accuracy loss. This work provides 516 × and 1.3 × 105 × improvements on LAE (Latency‐Area‐Energy) property, compared to the digital and analog CMOS activation circuits, respectively. With device‐algorithm co‐optimization, this work proposes a compact and energy‐efficient solution that pushes CIM‐based neuromorphic computing into a new paradigm. [ABSTRACT FROM AUTHOR]

A double-barrier quantum well is created using a larger band gap V-cut modified armchair graphene nanoribbon (AGNR) for the barrier region and a pristine AGNR with a smaller bandgap for the channel region. The numerical non-equilibrium Green’s function (NEGF) method, based on the pi-orbital tight-binding model, is employed to study the quantum transport properties of the device. The effects of various dimensional parameters, such as contact width, channel length, and distance between V-cuts in the barrier region, are investigated. The plot of the local density of states (LDOS) shows the formation of a single quantized quasi-energy state in the channel region, corresponding to a peak in transmission. The V–I characteristics of the device exhibit negative differential resistance (NDR) regions for a certain range of bias values. This device’s resonant tunneling performance parameters are compared with those of a similar, previously reported structure. [ABSTRACT FROM AUTHOR]

Carbon xerogel was prepared by a sol–gel technique by mixing formaldehyde with dissolved resorcinol in acetone solution using picric acid as a catalyst, followed by pyrolysis treatment at the desired temperature. X-ray diffraction analysis revealed that the obtained product has an amorphous phase, with an average grain size of approximately 2 nm. Scanning electron microscopy showed the existence of a mesoporous structure in the resorcinol–formaldehyde (RF) matrix with a pore size of about 50 nm. The electrical measurements carried out on our material showed interesting results. In fact, DC conductivity indicated that the xerogel is transformed from an insulating phase to a carbon-conducting phase under the pyrolysis temperature effect. The current–voltage (I–V) characteristics of the sample prepared at 650°C show different regions—an ohmic region at low applied voltages and a negative differential resistance (NDR) region at higher voltages, with the NDR phase appearing above a threshold voltage. Also, a hysteresis effect depending on the synthesis and measurement parameters was observed. The observed behaviors are explained in terms of the filament formation phenomenon and the Joule heating effect. These interesting behaviors are promising for threshold switching and neuromorphic computing applications. [ABSTRACT FROM AUTHOR]

Ferroelectric tunnel junctions (FTJs) have gained substantial attention as emerging electronic devices such as nonvolatile memory and artificial synapse, owing to their low power consumption and nonvolatile properties. In this work, a 2D semiconductor (2DS)/α‐In2Se3/metal FTJ structure is proposed that combines a semiconductor ferroelectric material and a semiconducting electrode. The incorporation of 2DS not only enhances the barrier height modulation but also provides an effective approach to mitigate the thermionic current leakage. Notably, the proposed MoS2/α‐In2Se3/Ti FTJs exhibit both room‐temperature negative differential resistance (NDR) effect and high tunnel electroresistance (TER) exceeding 104 simultaneously. Furthermore, the versatility of this structure extends to several 2DS (including MoS2, PdSe2, and SnSe2) and graphene electrodes to rationalize both tunneling and thermionic current transport mechanisms. The proposed 2DS/α‐In2Se3/metal FTJs present great superiority over existing structures in terms of robustness, temperature independence, high TER, and versatility for various potential application scenarios. [ABSTRACT FROM AUTHOR]

The article examines the main characteristics of parametric autogenerator thickness measurement transducers with a frequency output signal. The design of the proposed autogenerator transducers is based on transistor structures with negative differential resistance. Capacitors with round and rectangular covers are used as parametric transducers for measuring the thickness of materials, which are passive elements of autogenerator transducers, which greatly simplifies the design of devices for measuring the thickness of materials. Mathematical models of autogenerator transducers were developed based on the principle of converting the energy of a constant electric field into the energy of an alternating electric field, which made it possible to obtain the conversion and sensitivity functions of autogenerator transducers without using a rather complicated method of obtaining Kirchhoff equations from nonlinear equivalent circuits of parametric transducers. It is shown that the main contribution to the change in the conversion functions and the sensitivity equation is made by the change in the thickness of the measured material, which causes a change in the equivalent capacitance and negative differential resistance in the oscillating system of autogenerators, which changes the output frequency of the autogenerator transducers. The sensitivity of thickness measurement transducers varies from 5.31 kHz/μm to 7.5 kHz/μm in the thickness range from 0 to 500 μm. Autogenerator transducers for thickness measurement with frequency output do not require analog-digital transducers and amplifiers for further processing of informative signals, which significantly reduces the cost of informationmeasuring equipment, and when working at ultra-high frequencies, it is possible to transmit information over considerable distances. [ABSTRACT FROM AUTHOR]

Dynamical and statistical behaviour of the ionic particles in dissolved salts have long been known, but their hydration shells still raise unsettled questions. We engineered a “diffusion tunnel diode” that is structurally analogous to the well-known Esaki diode, but now concentration gradients serve as generalized voltages and the current means particle flow. In an equipartition sense, the hydrated ions enter a cavity as individual particles and later, upon increase of their concentration therein, they lose water molecules that henceforth are particles of their own. These temporarily attached water molecules thus are the tunnel current analogue. Unlike the original tunnel diode, our negative differential resistance has implications for the second law of thermodynamics, due to thermal effects of changes in the hydration shells.

Negative differential resistance (NDR) has garnered substantial interest in propelling the progression of next-generation electronic devices. Weyl semimetals (WSMs) are a potential candidate for NDR devices; however, the NDR effect in WSMs has not been investigated. Here, we propose the gate-tunable transistor to theoretically develop the NDR effect in WSMs for the first time. The maximum peak-to-valley current ratio (PVR) of over 2 with a high current density peak at the NDR regime is observed with the help of the control gate and periodicity. Notably, it is demonstrated that the NDR effect can present stability for varying temperatures, even at room temperature, making the proposed device to be applied into practice. Finally, the NDR performances of the proposed devices are better than those of the present literature. Our findings highlight the potential of the NDR devices utilizing WSMs.

The electrophysical and radiation characteristics of the original and irradiated electrons with E = 2 MeV GaAsP light emitting diodes were studied. The results of measurements of current-current characteristics in the range of 77 - 300 K are given. In the range of 180 - 77 K, a region of negative differential resistance was detected. The main characteristic parameters of light emitting diodes radiation are determined. The consequences of the effect of radiation defects on the emissivity and quantum yield of the studied structures are discussed.

Two-dimensional (2D) materials promise advances in electronic devices beyond Moore's scaling law through extended functionality, such as non-monotonic dependence of device parameters on input parameters. However, the robustness and performance of effects like negative differential resistance (NDR) and anti-ambipolar behavior have been limited in scale and robustness by relying on atomic defects and complex heterojunctions. In this paper, we introduce a novel device concept that utilizes the quantum capacitance of junctions between 2D materials and molecular layers. We realized a variable capacitance 2D molecular junction (vc2Dmj) diode through the scalable integration of graphene and single layers of stearic acid. The vc2Dmj exhibits NDR with a substantial peak-to-valley ratio even at room temperature and an active negative resistance region. The origin of this unique behavior was identified through thermoelectric measurements and ab initio calculations to be a hybridization effect between graphene and the molecular layer. The enhancement of device parameters through morphology optimization highlights the potential of our approach toward new functionalities that advance the landscape of future electronics. [ABSTRACT FROM AUTHOR]

Owing to rapid developments in spintronics, spin-based logic devices have emerged as promising tools for next-generation computing technologies. This paper provides a comprehensive review of recent advancements in spin logic devices, particularly focusing on fundamental device concepts rooted in nanomagnets, magnetoresistive random access memory, spin–orbit torques, electric-field modulation, and magnetic domain walls. The operation principles of these devices are comprehensively analyzed, and recent progress in spin logic devices based on negative differential resistance-enhanced anomalous Hall effect is summarized. These devices exhibit reconfigurable logic capabilities and integrate nonvolatile data storage and computing functionalities. For current-driven spin logic devices, negative differential resistance elements are employed to nonlinearly enhance anomalous Hall effect signals from magnetic bits, enabling reconfigurable Boolean logic operations. Besides, voltage-driven spin logic devices employ another type of negative differential resistance element to achieve logic functionalities with excellent cascading ability. By cascading several elementary logic gates, the logic circuit of a full adder can be obtained, and the potential of voltage-driven spin logic devices for implementing complex logic functions can be verified. This review contributes to the understanding of the evolving landscape of spin logic devices and underscores the promising prospects they offer for the future of emerging computing schemes. [ABSTRACT FROM AUTHOR]

Nanoparticles interconnected by insulating organic molecules exhibit nonlinear switching behavior at low temperatures. By assembling these switches into a network and manipulating charge transport dynamics through surrounding electrodes, the network can be reconfigurably functionalized to act as any Boolean logic gate. This work introduces a kinetic Monte Carlo-based simulation tool, applying established principles of single electronics to model charge transport dynamics in nanoparticle networks. We functionalize nanoparticle networks as Boolean logic gates and assess their quality using a fitness function. Based on the definition of fitness, we derive new metrics to quantify essential nonlinear properties of the network, including negative differential resistance and nonlinear separability. These nonlinear properties are crucial not only for functionalizing the network as Boolean logic gates but also when our networks are functionalized for brain-inspired computing applications in the future. We address fundamental questions about the dependence of fitness and nonlinear properties on system size, number of surrounding electrodes, and electrode positioning. We assert the overall benefit of having more electrodes, with proximity to the network's output being pivotal for functionality and nonlinearity. Additionally, we demonstrate an optimal system size and argue for breaking symmetry in electrode positioning to favor nonlinear properties. [ABSTRACT FROM AUTHOR]

Analog neuromorphic circuits use a range of volatile and non-volatile memristive effects to mimic the functionalities of neurons and synapses. Creating devices with combined effects is important for reducing the footprint and power consumption of neuromorphic circuits. This work presents an epitaxial SmNiO3/BaTiO3 electrical device that displays non-volatile memristive switching to either allow or block access to a volatile threshold switching regime. This behavior arises from coupling the BaTiO3 ferroelectric polarization to SmNiO3 metal-insulator transition; the polarization in the BaTiO3 layer that is in contact with the SmNiO3 layer modifies the device resistance continuously in a controllable, non-volatile manner. Additionally, the polarization state varies the threshold voltage at which the Joule-heating-driven insulator-to-metal phase transition occurs in the nickelate, which results in a negative differential resistance curve and produces a sharp, volatile threshold switch. Reliable current oscillations with stable frequencies, large amplitude, and a relatively low driving voltage are demonstrated when the device is placed in a Pearson-Ansonlike circuit. [ABSTRACT FROM AUTHOR]

Membranotronic devices are artificial neural membranes mimicing the functionality of biological neural networks. These devices rely on the emergence of negative differential resistance (NDR). A minimalistic physical model for membranotronic devices capable of generating NDR is presented. The model features a deformable membrane with holes that facilitate ion currents. The deformation of the membrane, induced by electrostatic pressure from an applied voltage, modulates these currents. The model comprises a well‐established mechanical framework for describing deformable membranes with holes, alongside a model for ionic current that considers temperature‐dependent ion mobilities. It is demonstrated that the model can faithfully reproduce NDR across a wide and physically realistic range of parameter combinations. Furthermore, the simulations reveal that the temperature of the electrolyte can exceed its boiling point, resulting in bubble formation. To mitigate this issue, materials with high heat transfer coefficients and low conductivity are recommended. In essence, the work bridges the gap between artificial membranotronic devices and biological neural networks by providing a robust physical model capable of emulating NDR, a key feature in the operation of such systems. This advancement in membranotronics holds great promise for the development of bioinspired soft artificial neuromimetic systems that closely mimic their biological counterparts. [ABSTRACT FROM AUTHOR]

The electrophysical and radiation characteristics of the original and irradiated electrons with E = 2 MeV GaAsP light emitting diodes were studied. The results of measurements of current-current characteristics in the range of 77 - 300 K are given. In the range of 180 - 77 K, a region of negative differential resistance was detected. The main characteristic parameters of light emitting diodes radiation are determined. The consequences of the effect of radiation defects on the emissivity and quantum yield of the studied structures are discussed. [ABSTRACT FROM AUTHOR]

The electrophysical and radiation characteristics of the original and irradiated electrons with E = 2 MeV GaAsP light emitting diodes were studied. The results of measurements of current-current characteristics in the range of 77 - 300 K are given. In the range of 180 - 77 K, a region of negative differential resistance was detected. The main characteristic parameters of light emitting diodes radiation are determined. The consequences of the effect of radiation defects on the emissivity and quantum yield of the studied structures are discussed. [ABSTRACT FROM AUTHOR]

A promising approach to advance electronics beyond static operations is to enhance state-ofthe- art systems by the functional diversification of transistors. Here, we experimentally demonstrate that an ultra-thin Ge channel implemented on a Si on insulator platform enables run-time switchable symmetric pand n-type field-effect transistor operability as well as the prominent feature of distinct room-temperature negative differential resistance. Temperature dependent bias spectroscopy is utilized to map electronic transport in these so called negative differential resistance mode reconfigurable transistors. Thereof, a profound understanding of the involved transport physics and electrostatic gating mechanisms is obtained and evaluated. Further, we show that a multi-gate negative differential resistance reconfigurable transistor can effectively replace a cascode of negative differential resistance devices, contributing to a smaller area footprint, and reduced latency of critical paths. Notably, the experimentally obtained multi-heterojunction transistors constitute the first chip-scale platform that combines efficient polarity control as well as sizeand energy-efficient room-temperature negative differential resistance, providing an inherent component of emerging neuromorphic computing.

This work presents a novel InGaAs/InP avalanche photodiode, fabricated in the separate absorption, grading, charge, and multiplication configuration operated at non-cryogenic conditions under low-frequency ramp gating. An optimized three stage InP multiplication layer of $1\mu m$ thickness offers an extended linear mode operation by reducing the punch-through voltage, and indefinitely increasing the avalanche threshold voltage. A large background dark current is observed following steady, and linear multiplication in approximately direct relationship with the ramp gating. For 1310 nm short-wave infrared, normal incidence pulsed illumination at instant-to-peak voltage ratios of $(0.11,0.2,0.6, 0.89, 0.98, 0.9)$ , a sort of negative differential resistance is incorporated into the device in a qualitative sense, owing to the illumination induced switching/variations in the intrinsic values of electron, and hole avalanche coefficients in the multiplication region. Under fixed illumination, an interesting deduction from the transient photo response is the slow quenching phenomenon prolonging $\sim 120 \mu s$ for all the electrical field establishments in the device. The related measurement scheme paves the way for futuristic ramp-driven InGaAs/InP APDs for detecting SWIR wavelengths under required low power consumption environments.

Perovskite semiconductors, as an emerging material, have gained widespread attention in the preparation of memristor devices with resistive switching (RS) behavior due to their excellent properties, such as ion migration, adjustable bandgap, and high OFF/ON ratio. The negative differential resistance (NDR) effect-coupled RS behavior has important prospects for the preparation of multifunctional devices due to its potential to break the limitations of Moore's law. In this work, the La0.7Sr0.3MnO3 films with different nanoscale thicknesses were prepared on fluorine-doped SnO2 (FTO) substrates by the radio frequency (RF) magnetron sputtering method as a functional layer of the memristor device. The Ag/La0.7Sr0.3MnO3/FTO memristor device achieves bipolar RS behavior with both nonvolatile memory and NDR effect, and the NDR-coupled RS effect can be successfully regulated by the functional layer thickness and bias voltage range. The conduction mechanism of the NDR-coupled RS phenomenon in the device can be explained by the formation and fracture of metal ion oxygen vacancy (V02+) conduction paths inside the functional layer. This work provides an important avenue for understanding the multiple physical mechanisms in memristor devices. [ABSTRACT FROM AUTHOR]

This article presents a theoretical study on the negative differential resistance (NDR) behavior of a bilaterally hydrogen-passivated Zigzag GeSe nanoribbon based single-gate field-effect transistor. It is focused on a 5-nm channel length device, and the study utilizes a simulation calculation that combines the density functional theory and non-equilibrium Green's function. In this study, a nitrogen atom is introduced as a substitutional dopant to replace the Ge atom in the source and drain regions of the GeSe field-effect transistor to created special symmetry structure. The numerical results demonstrate that the current peak-to-valley ratio (PVR) of the device can be effectively controlled by applying a gate voltage and up to 105 with the current peak value of 0.3 nA at room temperature (300 K). The device configuration described in this study meets the requirements of real-world industrial applications. These findings highlight the potential of GeSe Zigzag nanoribbon for future electronic device applications at nanoscale. [ABSTRACT FROM AUTHOR]

In this paper, the effect of temperature on Single-Electron Transistor (SET) electrical behavior is investigated. In particular, a study of the current-voltage (I-V) curves according to parameter (temperature and gate voltage) variation is presented. Among others, the interesting phenomenon of the N-type negative differential resistance is reported as the temperature increases from absolute zero (0 K) to room temperature. Finally, theoretical analysis and simulation shows that the choice of the appropriate temperature and gate-voltage combination the SET I-V curves demonstrates either a negative differential resistance region, a switching effect, or a simple resistance behavior. [ABSTRACT FROM AUTHOR]

Copyright of Informacije MIDEM: Journal of Microelectronics, Electronic Components & Materials is the property of MIDEM Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Based on two-dimensional green phosphorene, we designed two molecular electronic devices with zigzag (Type 1) and whisker-like (Type 2) configurations. By combining density functional theory (DFT) and non-equilibrium Green's function (NEGF), we investigated the electronic properties of Types 1 and 2. Type 1 exhibits an interesting negative differential resistance (NDR), while the current characteristics of Type 2 show linear growth in the current–voltage curve. We studied the electronic transport properties of Type 1 under uniaxial strain modulation and find that strained devices also exhibit a NDR effect, and the peak-to-valley ratio of device could be controlled by varying the strain intensity. These results show that the transport properties of green phosphorene with different edge configuration are different, and the zigzag edge have adjustable negative differential resistance properties. [ABSTRACT FROM AUTHOR]

The simultaneous control of the orientation and position of organic semiconductor nanowires remains a major challenge when integrating them into monolithic devices. In this study, tris(8‐hydroxyquinoline)aluminum(III) (Alq3) molecules are self‐assembled into single‐crystalline nanowires with consistent orientation and predictable positions by selective‐area graphoepitaxial growth. The nanowire orientation is determined by parallel nanogrooves on a periodically modified faceted sapphire surface, and the position is simultaneously defined using a shadow mask. Computational fluid dynamics simulations showed that the mass flow field over the sapphire surface is tailored by the mask, resulting in preferential nanowire nucleation around the hole centers and leaving sufficient free space for the subsequent growth. Accordingly, the number, length, and density of the nanowires can be controlled by adjusting the mask layout. The good alignment and predictable positions of these nanowires facilitated their subsequent device integration, eliminating laborious assembly steps and potential damage after nanowire growth. Measurements from an in situ integrated two‐terminal device based on the Alq3 nanowires revealed that the nanowires exhibit a remarkable negative differential resistance and fast photoresponse in the UV region. Overall, selective‐area graphoepitaxial growth provides a versatile protocol for fabricating site‐ and orientation‐controlled organic semiconductor nanowires for the monolithic fabrication of nanowire‐based devices. [ABSTRACT FROM AUTHOR]

Nanoparticles interconnected by insulating organic molecules exhibit nonlinear switching behavior at low temperatures. By assembling these switches into a network and manipulating charge transport dynamics through surrounding electrodes, the network can be reconfigurably functionalized to act as any Boolean logic gate. This work introduces a kinetic Monte Carlo-based simulation tool, applying established principles of single electronics to model charge transport dynamics in nanoparticle networks. We functionalize nanoparticle networks as Boolean logic gates and assess their quality using a fitness function. Based on the definition of fitness, we derive new metrics to quantify essential nonlinear properties of the network, including negative differential resistance and nonlinear separability. These nonlinear properties are crucial not only for functionalizing the network as Boolean logic gates but also when our networks are functionalized for brain-inspired computing applications in the future. We address fundamental questions about the dependence of fitness and nonlinear properties on system size, number of surrounding electrodes, and electrode positioning. We assert the overall benefit of having more electrodes, with proximity to the network’s output being pivotal for functionality and nonlinearity. Additionally, we demonstrate an optimal system size and argue for breaking symmetry in electrode positioning to favor nonlinear properties.

Analog neuromorphic circuits use a range of volatile and non-volatile memristive effects to mimic the functionalities of neurons and synapses. Creating devices with combined effects is important for reducing the footprint and power consumption of neuromorphic circuits. This work presents an epitaxial SmNiO3/BaTiO3 electrical device that displays non-volatile memristive switching to either allow or block access to a volatile threshold switching regime. This behavior arises from coupling the BaTiO3 ferroelectric polarization to SmNiO3 metal–insulator transition; the polarization in the BaTiO3 layer that is in contact with the SmNiO3 layer modifies the device resistance continuously in a controllable, non-volatile manner. Additionally, the polarization state varies the threshold voltage at which the Joule-heating-driven insulator-to-metal phase transition occurs in the nickelate, which results in a negative differential resistance curve and produces a sharp, volatile threshold switch. Reliable current oscillations with stable frequencies, large amplitude, and a relatively low driving voltage are demonstrated when the device is placed in a Pearson–Anson-like circuit.

Abstract Memristors, or more generally “memristive systems,” are nonlinear electric components that change their resistance depending on a set of state variables. Meanwhile, negative differential resistance (NDR) is an uncommon electrical property that occurs in a few nonlinear electric components. Such a nonlinear property is now widely used in amplifiers and oscillators. It finds that one of the bilayer‐type nickel‐dithiolene complexes shows nonlinear transport with the NDR property and self‐oscillates under a bias current by simply adding a capacitor in parallel. Surprisingly, the Lissajous figure of this molecular material shows a “pinched hysteresis loop” typical of a memristor, and an inductive reactance emerges when a bias current or voltage is applied to the sample. Herein, a new type of oscillator that uses the NDR and hidden inductive properties of a memristive system is reported. The findings suggest that a memristive system can mimic other passive elements, such as an inductor, and can oscillate itself without having them in the circuit. The oscillation mechanism is straightforward and applicable to a wide variety of memristive materials, including resistors with large negative temperature coefficients, discharge tubes, and even nerve cells in the living body.

Negative differential resistance (NDR) devices have recently attracted interest as multi-valued logic (MVL) circuits, owing to their folded electrical characteristics. However, with necessity of sophisticated computing systems, advanced NDR devices are required for stable low-power-consumption MVL circuits. Here, we developed van der Waals (vdW) NDR device with high peak-to-valley current ratio (PVCR) and low peak voltage (Vpeak), utilizing the passivation and doping effects of APTES layer as aminosilane coupling agent, at dielectric interface. The PVCR of NDR device reached 10 through reduced interface trap owing to the passivation effect of APTES silane group. Additionally, low Vpeak of NDR device was achieved at 0.2 V through doping effect of the APTES amine group. These PVCR and Vpeak values indicate the one of the best vdW NDR performance. Furthermore, stable logic state and low operation voltage of the ternary inverter were implemented using NDR device with high PVCR and low Vpeak. This NDR device represents a significant advancement for next-generation MVL technologies.

SrTiO3, a perovskite oxide, holds significant potential for application in the field of oxide electronics. Notably, its photoelectric activity in the low temperature regime, which overlaps with the quantum paraelectric state, exhibits remarkable characteristics. In this study, it is demonstrated that when photo‐excited with above band gap energy photons, SrTiO3 exhibits non‐linear transport of photocarriers and voltage‐controlled negative resistance, resulting from an intervalley transfer of photo‐induced electrons. As a consequence of the negative resistance, the photocurrent becomes unstable and spontaneously gives rise to low frequency Gunn‐like oscillations. [ABSTRACT FROM AUTHOR]

Devices with volatile memristive switching and self‐sustained relaxation oscillations have received significant attention for their use in neuromorphic computing and solving optimization problems. However, obtaining devices with stable response and reliable oscillation remains challenging. This work describes the utility of metal/oxide interlayers in achieving reliable device performance with tuneable characteristics using Nb‐Nb2O5‐Pt structures. Detailed physical characterization of the Nb/Nb2O5 interlayer region shows that it consists of a thin, near‐stoichiometric Nb2O5 and an NbOx layer with a graded oxygen content. The impact of these interlayers on device performance is assessed by investigating their switching characteristics and oscillation dynamics. It is shown that the presence of the interlayer has a direct impact on the memristive switching mode and parameters threshold switching characteristics parameters. These dependencies are explained with reference to a lumped‐element circuit model of the device and shown to be dominated by changes in device resistance caused by interlayer formation. Significantly, stable oscillation with tuneable frequency is obtained by increasing the thickness of the reactive Nb electrode. Then, by simulating an array of coupled oscillators, a unique Hamiltonian solver is demonstrated. These results provide pathways for optimizing volatile memristive switching characteristics and guidance on how such devices can be employed to solve combinatorial optimization problems. [ABSTRACT FROM AUTHOR]

In this paper, transport properties of a heterojunction based on (5, 0) carbon nanotube and (5,0) indium nitride nanotube were investigated using Density Functional Theory combined with Non-Equilibrium Green's Function formalisms. Based on the results reported here, under the low bias condition, Negative Differential Resistance (NDR) behavior could be observed due to the suppression of the conduction channels at a certain bias. The peaks and valleys in the transmission profile arising from resonant tunneling phenomenon confirmed the observed NDR. It, thus, appears that the (5, 0) CNT-InN nanotube heterojunction may be a favorable candidate for future nanoelectronic devices based on the resonant tunneling behavior. [ABSTRACT FROM AUTHOR]

Using the first-principles calculations based on density-functionaltheory (DFT) combined with nonequilibrium Green functions (NEGF), the electronic structure and transport properties of N-doped zigzag germanium selenide nanoribbon (ZGeSeNR) with different edge passivation atoms are systematically investigated. The calculated numerical results demonstrate the edge passivation atom exert a slight influence on the electronic properties of the N-doped ZGeSeNR. In contrast, the doping position of N atom has a great influence on the band structure of ZGeSeNR. Further, the current-voltage curves of Ndoped ZGeSeNR based device exhibit a negative differential resistance (NDR) phenomenon. Moreover, the peak of NDR behavior enters the low bias region when the doping concentration of N atom is reduced to 0.925%, and the peak-valley ratio (PVR) ups to 107. These results are very helpful for the future development of high-performance and low-power electronic devices based on the Ndoped ZGeSeNR. [ABSTRACT FROM AUTHOR]

Context: This study aims to investigate the electronic transport properties of tetracene molecule connected to gold (Au) electrodes with asymmetric anchoring groups. More specifically, we investigate the effect of asymmetric electrode coupling on the rectification ratio of tetracene-based molecular device. To introduce coupling asymmetry in these junctions, one end of the tetracene molecule is terminated with thiol (−SH) or isocyanide (−NC) while the other end with amine (−NH2) or nitro (−NO2) anchoring group. The results indicate that the electronic transport behavior is affected by the nature of molecule-electrode coupling, and the rectification ratio can be modulated by a proper choice of the anchoring groups. We reveal that the tetracene molecule when connected with isocyanide and amine combination exhibits remarkable rectifying performance (with a rectification ratio of 74) in contrast with other configurations. Furthermore, a prominent negative differential resistance (NDR) feature is observed when the molecule is connected with thiol as one of the anchors. Our present findings with excellent rectifying performance and negative differential resistance pave a new roadmap for designing multifunctional molecular devices. Methods: By applying non-equilibrium Green's function (NEGF) formalism combined with density functional theory (DFT) Atomistic Tool Kit software package, the electronic transport properties of tetracene molecule connected to gold electrodes with asymmetric anchoring groups have been investigated. The calculations were performed using the Perdew-Burke-Ernzerhof (PBE) parameterization of DFT within generalized gradient approximation (GGA) exchange-correlation functional. To improve calculation precision and save computational efforts, the molecule and anchor groups were double-ζ (DZ) polarized, while single-ζ (SZ) polarized basis set was used for gold electrodes. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials promise advances in electronic devices beyond Moore’s scaling law through extended functionality, such as non-monotonic dependence of device parameters on input parameters. However, the robustness and performance of effects like negative differential resistance (NDR) and anti-ambipolar behavior have been limited in scale and robustness by relying on atomic defects and complex heterojunctions. In this paper, we introduce a novel device concept that utilizes the quantum capacitance of junctions between 2D materials and molecular layers. We realized a variable capacitance 2D molecular junction (vc2Dmj) diode through the scalable integration of graphene and single layers of stearic acid. The vc2Dmj exhibits NDR with a substantial peak-to-valley ratio even at room temperature and an active negative resistance region. The origin of this unique behavior was identified through thermoelectric measurements and ab initio calculations to be a hybridization effect between graphene and the molecular layer. The enhancement of device parameters through morphology optimization highlights the potential of our approach toward new functionalities that advance the landscape of future electronics.

Abstract SrTiO3, a perovskite oxide, holds significant potential for application in the field of oxide electronics. Notably, its photoelectric activity in the low temperature regime, which overlaps with the quantum paraelectric state, exhibits remarkable characteristics. In this study, it is demonstrated that when photo‐excited with above band gap energy photons, SrTiO3 exhibits non‐linear transport of photocarriers and voltage‐controlled negative resistance, resulting from an intervalley transfer of photo‐induced electrons. As a consequence of the negative resistance, the photocurrent becomes unstable and spontaneously gives rise to low frequency Gunn‐like oscillations.

Negative differential resistance (NDR) in certain materials has been attributed to spontaneous emergence of symmetry‐breaking electrical current density localization from a previously homogeneous distribution, which is postulated to occur due to the nonequilibrium thermodynamic force of minimization of entropy production. However, this phenomenon has not been quantitatively predicted based on intrinsic material properties and an applied electrical stimulus. Herein an instability criterion is derived for localization of current density and temperature from a thermal fluctuation in a parallel conductor model of a thin film that is subject to Newton's law of cooling. The conditions for steady–state electro‐thermal localization is predicted, verifying a decrease in entropy production upon localization. Electro‐thermal localization accompanied by a decrease of entropy production is confirmed in a multiphysics simulation of current flow in a thin film. The instability criterion predicts conditions for spontaneous current density localization, relating symmetry breaking fundamentally to dynamical instability via Local Activity theory. [ABSTRACT FROM AUTHOR]

Context: This study aims to tune the transport properties of tetracene single-molecule junctions with the proper choice and placement of side and anchoring groups. For the operationalization of the molecule that was anchored with thiol or isocyanide groups, two different side groups, amine and nitro, in two different positions, were taken into consideration. For unperturbed tetracene molecule, a prominent negative differential resistance (NDR) feature at 1.8 V was observed with the isocyanide anchoring group while the thiol anchoring group exhibits a plateau region over a bias voltage of 2.2 to 3.2 V. At a bias voltage that is dependent on the chemical or structural change of side or anchoring groups, NDR feature of varying degree was seen in all configurations. Results show that the current flowing through the thiol-anchored molecule perturbed with the amine group at S' position is relatively larger than other configurations because of the smaller HOMO-LUMO gap and broader transmission peaks resulting in a peak to valley current ratio (PVCR) of 1.22. In addition, multiple NDR regions were realized in nitro-perturbed isocyanide-anchored molecule at S position. These results suggest their promising applications in switches, logic cells, and storage devices. Methods: The modeling and simulation of side-group mediated anchored tetracene molecule through two electrodic systems were studied using density functional theory (DFT) combined with non-equilibrium Green's function (NEGF) in Virtual NanoLab-AtomistixToolkit (ATK). The electron transport properties were calculated using Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA) exchange-correlation function. To optimize computing time, gold electrodes were single zeta polarized whereas the molecule, anchor groups, and side groups were double zeta polarized. [ABSTRACT FROM AUTHOR]

We studied light-emitting diodes (LEDs) with quantum dots маde on the basis of a solid solution of In0.21Ga0.79N. Measurements of current-voltage characteristics and electroluminescence characteristics were carried out in the range of 77 ÷ 300 K. On the current-voltage characteristics in the range of 77 ÷ 150 K, areas of negative differential resistance, as well as a fine structure of radiation spectra, were detected. The results of the influence of electron irradiation (Ee = 2 MeV) on electroluminescence characteristics intensity and quantum yield of the studied samples are presented; the features of the temperature dependence of the glow intensity of irradiated LEDs were revealed.

While synthesizing quasi-one-dimensional nanoribbons, there is a finite probability that edges have cove-edge defects. This paper focuses on the structural, electronic, and transport properties of cove-edge aluminum nitride nanoribbons (AlNNR) using density functional theory and the non-equilibrium Green's function (NEGF) method. The cove-edge AlNNRs are thermodynamically stable and exhibit metallic behavior. Interestingly, the calculated current–voltage characteristics of the cove-edge AlNNR-based nanodevices show negative differential resistance (NDR). The H-AlN-Cove nanodevice exhibits high peak-to-valley current ratio (PVCR) of the order of 107. The calculated PVCR of the H-AlN-Cove nanodevice is 106 times higher than that of the silicene nanoribbon (SiNR) and graphene nanoribbon (GNR), and 104 times higher than that of the phosphorene nanoribbon (PNR) and arsenene nanoribbons (ANR)-based devices respectively. The NDR feature with high PVCR provides a prospect for the cove-edge AlNNR in nanodevice applications. [ABSTRACT FROM AUTHOR]

The rapid development of technologies such as machine learning and artificial intelligence has further accelerated the growth of multi-value logic (MVL) computing nanodevices. However, current MVL nanodevices based on conventional materials face the challenges of low peak–valley ratio (PVR) and unstable spin filtering effects. Therefore, the intrinsic half-metal nanoscale MXene has become the answer to the development bottleneck of MVL nanodevices for its outstanding properties such as high Curie temperature and an appropriate band structure. The present work attempts to design spintronic magnetic tunnel junctions (MTJs) based on new predicted Sc2CHO as half-metallic electrodes and Sc2NHO as semiconductor-based scattering regions. Furthermore, we simulate its transport properties from density functional theory combined with nonequilibrium Green's function. And we have considered the effect of the length of the scattering region on MTJ performance. According to our calculations, the spintronic transport of the MTJs demonstrates up to perfect 100% polarizability spin currents stably due to the single-channel conduction capability of half-metal Sc2CHO. The MTJs exhibit a significant negative differential resistance (NDR) phenomenon, with the PVR of the type 2N reaching 1.28 × 106, the highest value among the two-dimensional spintronic nanodevices currently being theoretically explored. MTJs with a high PVR will be beneficial for the application and development of MVL nanodevices. The spin filtering effect and NDR phenomenon can be well-maintained as the scattering region length increases, and the PVR usually almost always remains 104. This is well reflected in the transmission spectra and molecular projection self-consistent Hamiltonian. The tunneling magnetoresistance phenomenon is also observed. [ABSTRACT FROM AUTHOR]

Abstract Negative differential resistance (NDR) in certain materials has been attributed to spontaneous emergence of symmetry‐breaking electrical current density localization from a previously homogeneous distribution, which is postulated to occur due to the nonequilibrium thermodynamic force of minimization of entropy production. However, this phenomenon has not been quantitatively predicted based on intrinsic material properties and an applied electrical stimulus. Herein an instability criterion is derived for localization of current density and temperature from a thermal fluctuation in a parallel conductor model of a thin film that is subject to Newton's law of cooling. The conditions for steady–state electro‐thermal localization is predicted, verifying a decrease in entropy production upon localization. Electro‐thermal localization accompanied by a decrease of entropy production is confirmed in a multiphysics simulation of current flow in a thin film. The instability criterion predicts conditions for spontaneous current density localization, relating symmetry breaking fundamentally to dynamical instability via Local Activity theory.

In this paper, the effect of temperature on Single-Electron Transistor (SET) electrical behavior is investigated. In particular, a study of the current-voltage (I-V) curves according to parameter (temperature and gate voltage) variation is presented. Among others, the interesting phenomenon of the N-type negative differential resistance is reported as the temperature increases from absolute zero (0 K) to room temperature. Finally, theoretical analysis and simulation shows that the choice of the appropriate temperature and gate-voltage combination the SET I-V curves demonstrates either a negative differential resistance region, a switching effect, or a simple resistance behavior.

Based on two-dimensional green phosphorene, we designed two molecular electronic devices with zigzag (Type 1) and whisker-like (Type 2) configurations. By combining density functional theory (DFT) and non-equilibrium Green’s function (NEGF), we investigated the electronic properties of Types 1 and 2. Type 1 exhibits an interesting negative differential resistance (NDR), while the current characteristics of Type 2 show linear growth in the current–voltage curve. We studied the electronic transport properties of Type 1 under uniaxial strain modulation and find that strained devices also exhibit a NDR effect, and the peak-to-valley ratio of device could be controlled by varying the strain intensity. These results show that the transport properties of green phosphorene with different edge configuration are different, and the zigzag edge have adjustable negative differential resistance properties.

Defects play a crucial role in modulating the properties of solid-state materials by inducing localized states that often benefit magnetic moments. Recently, direct experimental observations have shown the appearance of bunches of eight-atom-ring line defects in the T-phase VSe2 monolayer, a remarkable room-temperature two-dimensional magnetic metal. Using first-principles calculations, we have found that these line defects could enhance the magnetic moments, and half-metallicity (nearly 100% spin polarization) can be achieved in the structure with the densest defects. Furthermore, our analysis of the partial charge density distribution shows that a closer inter-defect distance between the d-states of vanadium atoms and p-states of selenium atoms increases the penalty of electrons occupying the spin-minority states. Moreover, we have discovered the high conductivity channel exhibits negative differential resistance characteristics within a bias range of 0.2 to 0.4 V (–0.4 to –0.2 V). Our findings broaden the scope of the applications of two-dimensional materials in spintronics and provide some theoretical guidance for the design of high-performance spintronic devices.