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Coexistence of resistive switching (RS) and negative differential resistance (NDR) has attracted much attention because NDR is beneficial for the realization of multilevel storage in RS devices. However, there is no report regarding the coexistence of NDR and RS for semiconductor quantum dots (QDs), which are suitable for memory devices. Here, RS behavior with the NDR effect based on cysteine-functionalized WS2 QDs has been demonstrated. A peculiar symmetric I–V loop with unipolar switching was observed during a complete voltage sweep cycle. The NDR effect can be adjusted by varying the voltage scan rate, and a peak-to-valley ratio as high as 9.85 has been attained. A model based on tunneling transport and carrier trapping has been proposed to explain NDR behavior accompanied by RS. The reproducibility of the RS and NDR has been evaluated after 100 sweeps under ambient conditions, giving evidence of a stable and high on–off resistance ratio of ∼104. This study may initiate a feasible way to implement a nonvolatile memory device based on cysteine-functionalized WS2 QDs. [ABSTRACT FROM AUTHOR]

We report a density functional non-equilibrium Green's function study of the electronic transport properties of nanoscale networks composed of Au metal clusters interconnected with thiolated molecules (1,4-benzenedithiol and 1,3,5-benzenetrithiol), connected in linear chains and branched (Y-, diamond-shaped) extended networks. Calculated current–voltage characteristics of the metal–molecular networks exhibited nonlinearities and rectification with negative differential resistance (NDR) peaks that became more pronounced with increasing chain length. A significant overlap of the energetically close delocalized molecular orbitals near the Fermi energy was observed, which likely combine and contribute to electron transport. The transmission spectra of the linear chains and branched networks showed an increase in the number and width of transmission peaks near the Fermi energy, as the structures were extended, indicating enhanced transmission. Peak-to-valley current NDR ratios as large as ~ 500 and rectification ratios of ~ 10 (0.25 V) were shown for linear and branched circuit elements, respectively, illustrating how charge transport through molecular-scale devices could be controlled with precision by modifying the structure and geometry of molecule–nanoparticle networks. These results provide a potential foundation and building block components for exploring and tailoring applications of metallic nanoparticle-molecular networks in various configurations for nanoelectronic devices and circuits, including memory, logic and sensing. [ABSTRACT FROM AUTHOR]

Negative differential resistance (NDR), a quantum nonlinear electron transport process, has long attracted research interest owing to its intriguing underlying physics and promising applications in high‐speed electronics. Here, the authors report the NDR behavior in (001)‐oriented ferroelectric Bi2WO6 using scanning tunneling microscopy (STM). The current–voltage characteristics of the diode configuration consisting of an STM tip over the [BiO]+‐[WO4]2−‐[BiO]+ terrace exhibit NDR features. Scanning tunneling spectroscopy combined with density functional theory calculations indicates that the observed NDR results from robust resonant tunneling through confined energy levels within the 2D [WO4]2− layer. The atomically resolved NDR found in such a transition metal oxide offers a unique band structure for novel ferroelectric‐based devices. [ABSTRACT FROM AUTHOR]

Negative differential resistance (NDR), a quantum nonlinear electron transport process, has long attracted research interest owing to its intriguing underlying physics and promising applications in high‐speed electronics. Here, the authors report the NDR behavior in (001)‐oriented ferroelectric Bi2WO6 using scanning tunneling microscopy (STM). The current–voltage characteristics of the diode configuration consisting of an STM tip over the [BiO]+‐[WO4]2−‐[BiO]+ terrace exhibit NDR features. Scanning tunneling spectroscopy combined with density functional theory calculations indicates that the observed NDR results from robust resonant tunneling through confined energy levels within the 2D [WO4]2− layer. The atomically resolved NDR found in such a transition metal oxide offers a unique band structure for novel ferroelectric‐based devices. [ABSTRACT FROM AUTHOR]

Structural and physical properties of armchair MoSi2N4 nanoribbons substitutionally doped by 3d transition metals (TM) at Mo sites are investigated using the density functional theory combined with the non-equilibrium Green’s function method. TM doping can convert the nonmagnetic direct semiconductor into device materials of a broad variety, including indirect semiconductors, half semiconductors, metals, and half metals. Furthermore the 100% spin filtering behavior in spin-up and spin-down half metals, a negative differential resistance with peak-to-valley ratio over 140 and a rectification effect with ratio over 130 are predicted, as well as semiconductor behavior with high spin polarization.

In this study, the negative differential resistance (NDR) phenomenon in two-terminal devices composed of pyrogallol-formaldehyde/ZrO2 composite materials is investigated. It is demonstrated that the NDR is caused by electrothermal effects, which can be observed through the dependence of the NDR on both voltage and temperature. Additionally, it is showed that the NDR peak current and peak/valley voltages can be effectively modulated using electrical pulses that produce mild Joule heating. This modulation arises from the formation of a conductive metastable state, which decays to equilibrium according to power law kinetics. It is suggested that this metastable state is generated through a reversible structural rearrangement induced by heat. The ability to electronically tune the NDR characteristics of carbon composites may have potential applications in electronically controlled oscillators and neuromorphic circuits.

Negative differential resistance (NDR) devices with a low peak-to-valley voltage difference (Δ V ) exhibit a high cut off frequency and low power consumption efficiency, which is significant for fabricating high-performance oscillators. However, achieving an ultralow Δ V is challenging. In this work, we report the first construction of an NDR device utilizing a van der Waals heterostructure composed of semimetallic Td-WTe 2 and semiconducting 2H-MoS 2 . Our findings reveal that the narrow energy region of the decreasing density of states (DOS) above the Fermi level of WTe 2 acts as a narrow band gap, facilitating type-III band alignment with MoS 2 and enabling band-to-band tunneling-based NDR transport. Notably, the NDR device exhibits an ultralow Δ V of approximately 0.01 V, which is at least an order of magnitude lower than previously reported values. This work not only introduces a new approach for NDR device fabrication but also provides new insights into the pivotal role of Td-WTe 2 in NDR transport.

In-sensor and near-sensor computing architectures enable multiply accumulate operations to be carried out directly at the point of sensing. In-sensor architectures offer dramatic power and speed improvements over traditional von Neumann architectures by eliminating multiple analog-to-digital conversions, data storage, and data movement operations. Current in-sensor processing approaches rely on tunable sensors or additional weighting elements to perform linear functions such as multiply accumulate operations as the sensor acquires data. This work implements in-sensor computing with an oscillatory retinal neuron device that converts incident optical signals into voltage oscillations. A computing scheme is introduced based on the frequency shift of coupled oscillators that enables parallel, frequency multiplexed, nonlinear operations on the inputs. An experimentally implemented 3 × 3 focal plane array of coupled neurons shows that functions approximating edge detection, thresholding, and segmentation occur in parallel . An example of inference on handwritten digits from the MNIST database is also experimentally demonstrated with a 3 × 3 array of coupled neurons feeding into a single hidden layer neural network, approximating a liquid-state machine. Finally, the equivalent energy consumption to carry out image processing operations, including peripherals such as the Fourier transform circuits, is projected to be <20 fJ/OP, possibly reaching as low as 15 aJ/OP.

AlN/GaN resonant tunneling diodes (RTDs) were grown separately on freestanding GaN (FS-GaN) substrates and sapphire substrates by plasma-assisted molecular-beam epitaxy (PA-MBE). Room temperature negative differential resistance (NDR) was obtained under forward bias for the RTDs grown on FS-GaN substrates, with the peak current densities (J p) of 175â€"700 kA/cm2 and peak-to-valley current ratios (PVCRs) of 1.01â€"1.21. Two resonant peaks were also observed for some RTDs at room temperature. The effects of two types of substrates on epitaxy quality and device performance of GaN-based RTDs were firstly investigated systematically, showing that lower dislocation densities, flatter surface morphology, and steeper heterogeneous interfaces were the key factors to achieving NDR for RTDs. [ABSTRACT FROM AUTHOR]

Negative differential resistance (NDR) devices are adequate candidates for the functional devices applicable to the next‐generation integrated circuit technology so‐called "Beyond CMOS." Here, a graphene velocity‐modulation‐barrier resonant‐tunneling diode operating at room temperature is proposed. The current–voltage characteristics of the device are analyzed using the non‐equilibrium Green's function technique. It is found that the Fermi velocity barrier in the well/barrier region manipulates the tunneling transmission probability by suppressing the Klein region and improving the resonant tunneling leading to NDR. For special values of velocity barriers, resonant states have maximum alignment with each other which increases peak current with a high peak to valley ratio (PVR). The width and the position of the NDR window are controlled and engineered by the device dimensions and the height of potential barriers. The smaller the device showed the better the NDR properties such as larger current density and maximum PVR. Taken together, the results reveal that adequate magnitude of the Fermi velocity in graphene barrier can be an impressive concept for the fabrication of emerging tunneling devices. [ABSTRACT FROM AUTHOR]

Protein-based electronics is one of the growing areas of bio-nanoelectronics, where novel electronic devices possessing distinctive properties are being fabricated using specific proteins. Furthermore, if the bio-molecule is analysed amidst different electrodes, intriguing properties are elucidated. This research article investigates the electron transport properties of l-aspartic acid (i.e. l-amino acid) bound to symmetrical electrodes of gold, silver, copper, platinum and palladium employing NEGF-DFT approach using self-consistent function. The theoretical work function of different electrodes is calculated using local density approximation and generalized gradient approximation approach. The calculated work function correlates well with the hole tunneling barrier and conductance of the molecular device, which further authenticate the coupling strength between molecule and electrode. Molecule under consideration also exhibits negative differential resistance region and rectification ratio with all the different electrodes, due to its asymmetrical structure. The molecular device using platinum electrodes exhibits the highest peak to valley ratio of 1.38 and rectification ratio of 3.20, at finite bias. The switching characteristics of different molecular device are justified with detailed transmission spectra and MPSH. These results indicate that l-aspartic acid and similar biomolecule can be vital to the growth of Proteotronics. [ABSTRACT FROM AUTHOR]

Purpose. Investigation of a moisture frequency transducer based on a moisture-sensitive capacitive element of a cylindrical structure with mesh electrodes for a system for measuring the amount and parameters of crude oil. Methodology. When constructing a moisture-sensitive element, an oscillatory method for measuring humidity was applied to achieve high sensitivity and accuracy while maintaining a low cost of the device. A moisture sensitive capacitive sensor based on a cylindrical structure with mesh electrodes was introduced into the measuring generator system based on a transistor structure with a negative differential resistance. Findings. Analytical expressions are obtained to describe the dielectric constant of an inhomogeneous mixture of water and oil. Using these equations, the capacitance of a moisture-sensitive sensor with mesh electrodes is calculated as a dependence of the moisture content of crude oil. It was determined that the capacitance of the moisture sensitive sensor increased from 20 to 44 pF when the mass moisture of crude oil changed from 0 to 30 %. The sensitivity of the developed capacitive sensor is 0.8 pF/% when using a measuring device in the form of a crude oil pipeline with a diameter of 50 millimeters. Originality. A mathematical model has been developed for the primary transducer of the moisture content of crude oil based on a cylindrical capacitor structure with net-like electrodes, which allows determining the value of the capacitance of the primary transducer of the moisture content of crude oil. A self-oscillator device for controlling the moisture content of crude oil has been developed on the basis of the structure of bipolar and field-effect transistors with a cylindrical capacitor structure with mesh electrodes. Practical value. Circuitry solutions for a moisture transducer for crude oil have been developed. The results of experimental studies showed that for the selected version of the moisture converter circuit, the output signal frequency decreased in the range from 1.617 to 1.27 MHz with a change in the mass moisture content of the Turkmen mixture from 0 to 30 %, respectively, and is close to a linear dependence. The wide frequency range of the output signal of the secondary converter with the frequency output of the measured information increases the accuracy of moisture measurement in crude oil by an order of magnitude. [ABSTRACT FROM AUTHOR]

We report herein existence of a critical tunnelling width beyond which graphitic tunnelling nanostructures exhibit asymmetric spin polarized negative differential resistance feature. Our theoretical foray quite clearly establishes that even with a simple two‐dimensional tunnelling nanostructure created by an assembly of ferromagnetic graphitic carbon nitride (g‐C4N3) electrodes separated by insulating graphene sheet of variable lengths, there exists a critical tunnelling width at which the system switches from symmetric to asymmetric negative differential resistance feature. Presence of robust spin filer efficiency (100 %) over a wide range of bias variation (−1.0 to +1.0 V) added with negative differential resistance action makes the device with shorter tunnelling width of 22.36 Å and 31. 96 Å potentially useful as multifunctional spintronic device. However, at the critical tunnelling width of 36.69 Å and beyond the forward bias negative differential resistance features completely switches off and same is observed only in reverse bias. This switching action certainly opens up the prospect of logic gates operation in quantum circuits. Results obtained has been explained through transmission spectra, transmission pathways and molecular projected self‐consistent Hamiltonian states analysis. Emergence of asymmetric I−V curve beyond critical tunnelling width has been explained by examining differences in spin injection coefficients. [ABSTRACT FROM AUTHOR]

We report herein existence of a critical tunnelling width beyond which graphitic tunnelling nanostructures exhibit asymmetric spin polarized negative differential resistance feature. Our theoretical foray quite clearly establishes that even with a simple two‐dimensional tunnelling nanostructure created by an assembly of ferromagnetic graphitic carbon nitride (g‐C4N3) electrodes separated by insulating graphene sheet of variable lengths, there exists a critical tunnelling width at which the system switches from symmetric to asymmetric negative differential resistance feature. Presence of robust spin filer efficiency (100 %) over a wide range of bias variation (−1.0 to +1.0 V) added with negative differential resistance action makes the device with shorter tunnelling width of 22.36 Å and 31. 96 Å potentially useful as multifunctional spintronic device. However, at the critical tunnelling width of 36.69 Å and beyond the forward bias negative differential resistance features completely switches off and same is observed only in reverse bias. This switching action certainly opens up the prospect of logic gates operation in quantum circuits. Results obtained has been explained through transmission spectra, transmission pathways and molecular projected self‐consistent Hamiltonian states analysis. Emergence of asymmetric I−V curve beyond critical tunnelling width has been explained by examining differences in spin injection coefficients. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Mn-L-based multifunctional molecular spintronic device is designed. • Spin-polarized transport properties are strongly dependent on the magnetic configuration. • High-performance spin-filtering, spin-rectifying, giant magnetoresistance and negative differential resistance effects are realized in the designed device. A transition metal coordination complex Mn-L-based multifunctional molecular spintronic device is proposed and its spin-polarized transport properties in two magnetic configurations (parallel and anti-parallel alignments) are evaluated using the first-principles density functional theory and non-equilibrium Green's function method. Four high-performance physical effects, including spin-filtering, spin-rectifying, giant magnetoresistance and negative differential resistance, are revealed in the proposed device. The physical mechanisms are analyzed through the spin-resolved bias-dependent transmission spectra, and projected device density of states spectra. These results demonstrate that the proposed system holds great promise in developing the multifunctional molecular spintronic devices. [ABSTRACT FROM AUTHOR]

Atomically thin materials have the capability to construct semiconductor heterojunction devices incorporating a quantum-well structure and barriers on both sides, showcasing features like negative differential resistance (NDR). Quantum-well structures exhibit discrete states, allowing electrons/holes to tunnel through and generate non-monotonic current–voltage characteristics, such as NDR. In this investigation, we present a series of functionalized one-dimensional (1D) boron nitride nanoribbons (BNNRs) as channel materials with anisotropic electronic properties. Using a first-principle approach, we calculate the quantum transport of anticorrelated BNNRs positioned between group III–V atoms and passivated with gaseous atoms. Our findings unveil resonant electron tunneling due to multi-barrier channels with periods comparable to the electron wavelength. We also assess the Ohmic transport regime for the proposed structures and observe NDR characteristics, noting significant peak-to-valley current ratios in certain cases. Analyzing the transmission spectrum and bond current graph for NDR peaks and valleys aids in comprehending this phenomenon. Furthermore, by tracing transmission pathways, we identify the diffusive transport regime in these structures. Additionally, we demonstrate the hole-dominant nature of charge carriers through voltage drop curves within the scattering region. The favorable current–voltage characteristics of functionalized BNNRs could find applications in the next generation of field-effect transistors and resonant tunneling diodes. This investigation delves into exotic quantum states in 1D hBN nanostructures, serving as a foundation for future integrated quantum and photonic circuits applicable in quantum technology. • Thin BNNRs enable semiconductor devices, showing NDR in current–voltage. • Quantum-well structures allow electron–hole tunneling, yielding NDR. • BNNRs with anisotropic properties serve as channels, analyzed via first-principles. • Resonant electron tunneling in multi-barrier channels, NDR with high ratios. • Insights into NDR through transmission spectra, bonds, voltage drops; BNNRs' potential for future tech. [ABSTRACT FROM AUTHOR]

ight emitting diodes based on gallium arsenide-phosphide solid solutions were studied. Negative differential resistance regions were identified at lower temperatures T ≤ 130 K. Irradiation of diodes by electrons (E = 2 MeV) leads to the increase in the differential resistance, change in the contact potential difference, and a drop in the radiation intensity. These effects are due to the influence of deep radiation defects levels and surface states, activated by high levels of the ionization excitation peculiar to electron irradiation.

Abstract In this work, Ru-based RRAM devices with atomic layer deposited AlOy/HfOx functional layer were fabricated and studied. A negative differential resistance (NDR) behavior was observed during the voltage set process, and its physical origin was explored. Based on the physics understanding of the resistive switching, the measured NDR behavior is believed to be associated with the partially unipolar reset effect, which is due to the recombination between oxygen vacancies and the thermally released oxygen ions from the RuO2 interface layer. The measured electrical characteristics and X-ray photoelectron spectroscopy (XPS) results verified the physical interpretation.

Negative differential resistance (NDR) region was established in Si/GaAs tunnel junction (TJ) formed by single crystalline nanomembrane (NM) transfer method. P + Si NM was transfer-printed onto n + GaAs epi-wafer, leading to the formation of Si/GaAs pn TJ diode comprised of crystalline semiconductors with no biaxial strain. Atomic-scale features at the Si/GaAs junction interface were analyzed by high-resolution transmission-electron-microscopy. The mechanism for NDR phenomenon in the electrical characteristics of Si/GaAs TJ diode was explained by the energy band diagram with a quantum mechanical band-to-band tunneling of carriers. The peak-to-valley-ratio value of TJ diode was 2.32. The results can be applicable to the fabrication of low-power circuits with a combination of lattice-mismatched crystalline semiconductors.

The electronic transport behavior of a sulflower molecule sandwiched between metal leads by S atom connecting apex Au or Ag atoms was investigated using a first-principles study by current-voltage characteristics, transmission spectrum and local density of states. Negative differential resistance (NDR) effect which originates from Coulomb blockade driven by bias was obtained. We also found that the differential conductance can be modulated by the metal leads with different work functions, which promise the potential applications in molecular devices in the future. [ABSTRACT FROM AUTHOR]

Paper electronics have been fast developed in recent years due to their degradability and recyclability; however, most of them are barely equipped with logic functions, impeding them from becoming autonomous on-paper systems. To provide a working unit for logic implementations, a paper field-effect transistor (FET) with a clay-graphite channel that demonstrated negative differential resistance (NDR) is fabricated in this study. The device exhibited a p-type semiconductor characteristic with an optical bandgap of ∼1.97 eV according to photoluminescence analysis, resulting from considerable defective graphite mixed with clay in the channel. Considering that the NDR behavior is theoretically predicted to be tunable by the contact resistance, we fabricated FETs with different contact resistances and observed that the NDR behavior occurred in devices with relatively lower contact resistance. The NDR effect is also tunable by varying the gate voltage, which matches well with simulation results. The possible mechanism for the NDR behavior is the decrease in carrier drift velocity induced by band-to-band tunneling, associated with impurities-induced trapping states and gate-induced confined states. This work provides a promising and easy pathway to develop digital components using paper electronics in the near future. [Display omitted] • A paper field-effect transistor with clay-graphite channel exhibits negative differential resistance (NDR) behavior. • The device shows a p-type characteristic and an optical bandgap ∼1.97 (eV) due to defective graphite mixed with clay. • The NDR behavior is tunable by the contact resistance and the gate voltage. • The NDR behavior is believed to be originated from the decrease of drift velocity induced by band-to-band tunneling. [ABSTRACT FROM AUTHOR]

We investigate the effect of the reversible electronic switching of thin polymer films (40–1300 nm) into a metal-like state under the action of low uniaxial mechanical pressure (0–240 kPa). The dependences of the critical pressure on the effective work function of the electrodes, applied voltage, and polymer-film thickness are studied. An increase in the effective work function leads to an increase in the critical pressure, as well as an increase in the thickness of the polymer film. The results are interpreted in terms of changes in the parameters of the potential barrier at the metal–polymer interface with a change in the work function of the metal. The size dependence of the conductivity on pressure correlates with a change in the activation energy of trapping centers in the polymer film due to a change in supramolecular ordering. [ABSTRACT FROM AUTHOR]

Electronic structures and transport in armchair PtS2 nanoribbons are studied based on the density functional theory. Bare nanoribbons are magnetic metal with strong negative differential resistance (NDR). In an environment of low hydrogen concentration, the nanoribbons convert to the magnetic semiconductor. The conductance becomes negligible under a bias below 1 V due to the mismatch of wave functions between edge and bulk states. However, a transition from magnetic semiconductor to nonmagnetic metal can occur if a strain of 7% is applied. The stretched nanoribbons then become conductive again with an even stronger NDR. The hydrogen concentration can be used to further modulate the energy gap, the edge magnetism, and conductivity by varying the adsorbed H atoms on the edge. Our study highlights the potential of armchair PtS2 nanoribbons for spintronic nanodevices controlled by both strain and hydrogenation. [ABSTRACT FROM AUTHOR]

Herein, the possibility of changing the conductivity of thin‐film systems consisting of two metals separated by an insulator (metal–insulator–metal, MIM) is shown. The electrophysical properties are studied in three systems: Fe/MgO/Ni, Fe/MgO/Co, and Fe/MgO/Fe + C (Fe doped with carbon). The resulting inhomogeneity in thickness of the dielectric layer over the junction area promotes the appearance of local conduction regions. This makes it possible to change the type of conductivity from tunneling to semiconducting. As a result, a region with negative differential resistance is observed in I–V characteristics of MIM systems. The processes of electromigration during the alloying of one of the metal layers are considered. Presence of such processes is confirmed by the results of dynamic and static measurements of conductivity and corresponding assessments. Exposure of the sample in laboratory atmosphere at room temperature for several tens of days provides asymmetrical I–V characteristics. This indicates the rectifying properties of the contact—characteristic of the conductivity of the Schottky diode. The use of MIM systems with the described properties is considered promising for application in modern electronic devices as basic elements and memory cells. [ABSTRACT FROM AUTHOR]

The optical characteristics of the GaAs1-хPх output LEDs and LEDs irradiated with electrons with Е = 2 MeV, Ф = 1015 ÷ 1016 cm-2 were studied. The width of the band gap of the GaAs1-хPх (х = 0.45) solid solution was estimated. Its growth is caused by the heating of carriers by the field of the p-n junction. The damage coefficients of the lifetime of minority charge carriers for irradiated GaAsP LEDs have been calculated and the consequences of exposure to radiation on the operational parameter Т1, which determines the thermal stability of the diodes, have been analyzed. [ABSTRACT FROM AUTHOR]

The negative differential resistance (NDR) in ZnO/Nb:SrTiO3 heterojunctions is found to be strongly dependent on negative pulse amplitude/width and compliance current. When a small or short negative pulse is applied, the NDR feature remains almost the same. With the negative pulse amplitude or width increasing, the NDR feature gradually fades down and shifts to a larger negative bias. Meanwhile, the NDR intensity increases markedly without significant shift with increase of the compliance current. Interestingly, the low‐resistance state and NDR location are found to exhibit exactly the same trend when varying the negative pulse amplitude, width, and compliance current. The dependence of the NDR intensity and location on the pulse amplitude/width and compliance current can be well understood from the variance of concentration of ionized oxygen vacancies and the depletion layer width, respectively. This will promote the application of NDR devices. [ABSTRACT FROM AUTHOR]

Negative differential resistance (NDR) in NbOx films attracts attention for potential application in neuromorphic computing. A continuous S‐type and abrupt snapback NDR characteristics are reported for NbOx devices. The NDR characteristics are expected to depend on the nature of the switching path in NbOx. Previous NDR studies have been performed mainly on amorphous NbOx films with an electroforming process to create a switching path. Herein, the NDR characteristics of a forming‐free NbOx device with crystalline NbO2 phases are investigated and these are compared with those of an amorphous NbOx device with forming. The forming‐free NbOx device exhibits a secondary abrupt snapback NDR in addition to the initial S‐type NDR, possibly due to a metal–insulator transition in the NbO2 phases. Meanwhile, the amorphous NbOx devices only show a continuous S‐type behavior. [ABSTRACT FROM AUTHOR]

In the quest to push the contemporary scientific boundaries in nanoelectronics, Ge is considered a key building block extending device performances, delivering enhanced functionalities. In this work, a quasi‐1D monocrystalline and monolithic Al–Ge–Al nanowire heterostructure are embedded into a novel field‐effect transistor architecture capable of combining Ge based electronics with an electrostatically tunable negative differential resistance (NDR) distinctly observable at room temperature. In this regard, a detailed study of the key metrics of NDR in Ge is presented. Most notably, a highly efficient and low‐footprint platform is demonstrated, paving the way for potential applications such as fast switching multi‐valued logic devices, static memory cells, or high‐frequency oscillators, all implemented in one fully complementary metal–oxide–semiconductor compatible Al‐Ge based device platform. [ABSTRACT FROM AUTHOR]

The features of the current-voltage characteristics of LEDs obtained on the basis of GaP-GaAsP solid solutions are considered. The results of studies of the effect of electron irradiation (E = 2 MeV, F = 3 · 1014 ÷ 2.6 · 1016 cm-2 ) on the main electrophysical parameters of GaAs1-xPx diodes (x = 0.85 – yellow, x = 0.45 – orange) are given. The increase of differential resistance, the series resistance of the base, and barrier potential are revealed. The processes of recovery of the investigated quantities during isochronous annealing are analyzed, the mechanisms of degradation-recovery phenomena are discussed. [ABSTRACT FROM AUTHOR]

In this paper, we introduce three new structures of a cylindrical gate-all-around nanowire (NW) field-effect transistor (FET) to achieve negative differential resistance (NDR) and negative transconductance (NTC) behaviors. In the first structure, only one metal is implanted in the channel near the drain of the dual-material cylindrical gate-all-around NWFET based on the energy band profile modulation to obtain the NDR behavior. To achieve NTC behavior, another metal is implanted in the channel near the source; therefore, the second structure has both the NDR and NTC behaviors. In the final structure, the use of a triple-metal gate is proposed to improve the peak-to-valley current ratio. The NTC behavior occurs when the increase in VGS creates a positive lateral electric field in the channel, which causes the potential barrier tunneling (PBT) to decrease. The cause of the positive electric field formation is the cavity in the channel's potential barrier due to implanted metals. Furthermore, by increasing VDS, the high electron scattering caused by the high electric field at the beginning of the drain region is increased and causes the electron drift velocity and IDS to decrease. Consequently, the NDR behavior is achieved. The structures are carefully simulated using numerical simulation based on non-local tunneling, and also the transfer characteristics (IDS − VGS) and the output characteristics (IDS − VDS) are attentively analyzed and examined. [ABSTRACT FROM AUTHOR]

Range‐separated hybrid (RSH) functionals have been recently used to overcome the tendency of traditional density functional theory (DFT) calculations to overestimate the conductance of molecular junctions. Non‐equilibrium conditions are addressed following non‐equilibrium Green's function (NEGF) formulation with RSH functionals to study negative differential resistance (NDR) in molecular junctions of oligo phenylene ethylene derivatives linking gold electrodes. It is shown that the RSH‐NEGF calculations indicate NDR onset bias that agrees well with measured trends, associate NDR to orbital localization at the drain contact, and analyze the role of junction asymmetry in NDR. The RSH‐NEGF results are also compared with alternative DFT‐NEGF combinations to highlight the importance of basing the computational study on a functional that achieves physically significant frontier orbitals. Finally, the effects of thermally accessible molecular fluctuations to enhance the NDR conductance drop are also discussed. [ABSTRACT FROM AUTHOR]

Neuromorphic nanoelectronic devices that can emulate the temperature-sensitive dynamics of biological neurons are of great interest for bioinspired robotics and advanced applications such as in silico neuroscience. In this work, we demonstrate the biomimetic thermosensitive properties of two-terminal V 3 O 5 memristive devices and showcase their similarity to the firing characteristics of thermosensitive biological neurons. The temperature-dependent electrical characteristics of V 3 O 5 -based memristors are used to understand the spiking response of a simple relaxation oscillator. The temperature-dependent dynamics of these oscillators are then compared with those of biological neurons through numerical simulations of a conductance-based neuron model, the Morris-Lecar neuron model. Finally, we demonstrate a robust neuromorphic thermosensation system inspired by biological thermoreceptors for bioinspired thermal perception and representation. These results not only demonstrate the biorealistic emulative potential of threshold-switching memristors but also establish V 3 O 5 as a functional material for realizing solid-state neurons for neuromorphic computing and sensing applications.

The application of hardware-based neural networks can be enhanced by integrating sensory neurons and synapses that enable direct input from external stimuli. This work reports direct optical control of an oscillatory neuron based on volatile threshold switching in V 3 O 5 . The devices exhibit electroforming-free operation with switching parameters that can be tuned by optical illumination. Using temperature-dependent electrical measurements, conductive atomic force microscopy (C-AFM), in situ thermal imaging, and lumped element modelling, it is shown that the changes in switching parameters, including threshold and hold voltages, arise from overall conductivity increase of the oxide film due to the contribution of both photoconductive and bolometric characteristics of V 3 O 5 , which eventually affects the oscillation dynamics. Furthermore, V 3 O 5 is identified as a new bolometric material with a temperature coefficient of resistance (TCR) as high as -4.6% K -1 at 423 K. The utility of these devices is illustrated by demonstrating in-sensor reservoir computing with reduced computational effort and an optical encoding layer for spiking neural network (SNN), respectively, using a simulated array of devices., (© 2024 The Authors. Advanced Materials published by Wiley‐VCH GmbH.)

Based on the consideration of physical processes in a tunnel-resonant diode under the action of a magnetic field, the construction of an autogenerating magnetic field sensor with a frequency output signal is proposed. The use of devices with negative differential resistance makes it possible to significantly simplify the design of magnetic field sensors in the entire RF frequency range. Depending on the operating modes of the sensor, an output signal can be obtained in the form of harmonic oscillations, as well as in the form of pulse oscillations of a special form. The study of the characteristics of the magnetic field sensor is based on the complete equivalent circuit of the tunnel-resonant diode. The equivalent circuit takes into account both the capacitive and inductive properties of the tunneling resonant diode. The inductive component exists under any operating conditions, as a result of the fact that the current flowing through the device is always lagging behind the voltage that caused it, which corresponds to the inductive response of a tunnel-resonant diode.

In the present study, an n-ZnO nanorods (NRs)/p-degenerated diamond tunneling diode was investigated with regards to its temperature-dependent negative differential resistance (NDR) properties and carrier tunneling injection behaviors. The fabricated heterojunction demonstrated NDR phenomena at 20 and 80°C. However, these effects disappeared followed by the occurrence of rectification characteristics at 120°C. At higher temperatures, the forward current was increased, and the turn-on voltage and peak-to-valley current ratio (PVCR) were reduced. In addition, the underlying mechanisms of carrier tunneling conduction at different temperature and bias voltages were analyzed through schematic energy band diagrams and semiconductor theoretical models. High-temperature NDR properties of the n-ZnO NRs/p-degenerated diamond heterojunction can extend the applications of resistive switching and resonant tunneling diodes, especially in high-temperature, and high-power environments.

In this paper, we investigated the effect of the central AlGaAs barrier width Lb2 in a resonant tunneling diode (RTD) composed by triple barriers on the current-voltage characteristics, and electronic density of free carriers. In addition, this is a comparative study on the current-voltage characteristics that are produced by a double-barriers and triple-barriers RTD. Our simulation was performed using a non-equilibrium Green’s formalism (NEGF). The results showed that the double-barrier RTD produced a higher current density than the triple-barrier RTD. However, in the triple-barrier RTD, the maximum current was obtained for lower applied bias compared to the double-barrier RTD. The peak to valley current ratio (PVCR) has been evaluated and our results indicate that the double-barrier RTD can produces a higher ratio values compared to those produced by triple-barrier RTD. Our findings also showed that for the triple-barrier RTD, the negative differential resistance (NDR) depended on the width Lb2 of the central barrier. By reducing Lb2, the NDR decreased dramatically and disappeared completely for Lb2 = 3 nm. These results open the door for designing a double and triple-barrier RTD with suitable negative differential resistances. The RTD simulation was performed using the Nanohub tool, which confirms the various results presented in this paper.

We report large amplitude modulation waveforms as large as ~ 10 V using vanadium dioxide micro-channel devices operating under current-controlled conditions. The self-sustained electrical oscillations were generated by controlling the applied current in the negative differential resistance region of the investigated devices. An appropriate value of internal capacitance was achieved as parasitic capacitance in the device structure to stabilize the electrical oscillations. This eliminates the need of an external pulsed source or any external passive component connected to the micro-channel devices. Amplitude and frequency of the oscillation were tuned by illuminating the device micro-channel with an external laser. An equivalent circuit model was developed to simulate the waveforms. A good agreement between experiment and simulation was verified.

Abstract We have studied the electronic structure and the current-voltage (I-V) characteristics of one-dimensional InSe nanoribbons using the density functional theory combined with the nonequilibrium Green’s function method. Nanoribbons having bare or H-passivated edges of types zigzag (Z), Klein (K), and armchair (A) are taken into account. Edge states are found to play an important role in determining their electronic properties. Edges Z and K are usually metallic in wide nanoribbons as well as their hydrogenated counterparts. Transition from semiconductor to metal is observed in hydrogenated nanoribbons HZZH as their width increases, due to the strong width dependence of energy difference between left and right edge states. Nevertheless, electronic structures of other nanoribbons vary with the width in a very limited scale. The I-V characteristics of bare nanoribbons ZZ and KK show strong negative differential resistance, due to spatial mismatch of wave functions in energy bands around the Fermi energy. Spin polarization in these nanoribbons is also predicted. In contrast, bare nanoribbons AA and their hydrogenated counterparts HAAH are semiconductors. The band gaps of nanoribbons AA (HAAH) are narrower (wider) than that of two-dimensional InSe monolayer and increase (decrease) with the nanoribbon width.

Discrepancies exist between the theoretically predicted and experimentally measured performance of band-to-band tunneling devices, such as Esaki diodes and tunnel field-effect transistors (TFETs). We resolve this discrepancy for highly-doped, direct-bandgap Esaki diodes by successfully calibrating a semi-classical model for high-doping-induced ballistic band-tails tunneling currents at multiple temperatures with two In0.53Ga0.47As Esaki diodes using their SIMS doping profiles, C-V characteristics and their forward-bias current density in the negative differential resistance (NDR) regime. The current swing in the NDR regime is shown not to be linked to the band-tails Urbach energy. We further demonstrate theoretically that the calibrated band-tails contribution is also the dominant band-tails contribution to the subthreshold swing of the corresponding TFETs. Lastly, we verify that the presented procedure is applicable to all direct-bandgap semiconductors by successfully applying it to InAs Esaki diodes in literature.

Ferroelectric-Hf1-xZrxO2 FETs on silicon on insulator (SOI) are modeled and demonstrated with improvement on subthreshold swing (SS) and hysteresis (VT-shift), which is based on the capacitance matching concept. The minimum reverse SS = 45 mV/dec and 52 mV/dec are obtained experimentally for SOI and bulk-Si, respectively. The steep SS range (

Diodes with a resonant tunneling border are studied as possible sources of THz range. The diodes represent planar two-terminal structures containing a conductive channel and an active lateral border. The lateral border is an AlGaAs/GaAs-based double barrier resonant tunneling structure sandwiched between the channel and metal electrode. It electrically connects to an ohmic contact forming the anode. The operating principle of diodes is based on the use of transfer electron effect in the channel and electron transport throw the lateral border that can result in an increase in the oscillation frequency and extension of operating frequency range. The analysis was performed using ensemble Monte Carlo technique. Oscillation efficiency and frequency properties of the diode are determined. The relation between the maximum efficiency at a specific frequency and the magnitude of the applied bias is shown. It is found that the maximum efficiencies for lower operating frequencies correspond to large bias voltages, while ones at high frequencies are obtained for low bias voltages. Thus, it is possible to create a voltage-controlled oscillation source. The influence of a position of RTB and impurity doping on the generation efficiency of the diode has been investigated. The position of the active lateral border closer to the cathode contact results in a decrease in the generation efficiency and the rise in the oscillation frequency is demonstrated. The possibility to obtain generation in the range from 50 to 550 GHz is shown. The maximum oscillation efficiency is close to 10 % and corresponds to 110 GHz. [ABSTRACT FROM AUTHOR]