Gallium nitride (GaN) is a well-investigated material that is applied in many advanced power electronic and optoelectronic devices due to its wide bandgap. However, derivatives of its monolayer form, such as bilayer structures, have rarely been reported. We study herein the electronic and optical properties of GaN bilayer structures that are rotated in the plane at several optimized angles by using

A dual-diamond-ring photonic crystal fiber (PCF)-based sensor is proposed and analyzed herein for the detection of the concentration of alcohol in aqueous solution. Commercially available finite element method (FEM)-based simulation software (COMSOL Multiphysics® version 4.3b) is utilized to conduct a rigorous numerical investigation. The sample is injected inside the fiber. Several crucial optical

An analysis of the application of neural networks as a reliable, precise, and fast tool in open-cell photoacoustics setups for the recognition of microphone effects in the frequency domain from 10 Hz to 100 × 104 Hz is presented. The network is trained to achieve simultaneous recognition of microphone characteristics, which are the most important parameters leading to the distortion of photoacoustic

The aim of this work is to improve the estimation of parameters of solar photovoltaic models. An approach based on lightning attachment procedure optimization, which takes into account the uncertainties of measurements, is proposed. The approach includes three steps: the extraction of the parameters in a conventional manner, the determination of the partial uncertainties of all the parameters, and

All-optical reversible logic gates can play crucial roles in the next generation of all-optical computing systems. In this paper, we will propose and design an all-optical Toffoli gate using photonic crystal-based nonlinear ring resonators. The proposed structure has three input and three output ports. There is a one-by-one mapping between the input and output ports; therefore, the proposed structure

A new two-dimensional analytical model is proposed for the electrical attributes of a gate-all-around heterojunction tunnel field-effect transistor, including the potential distribution, lateral and vertical electric fields, drain current, subthreshold swing, and threshold voltage. The potential distribution in the device is obtained by using the two-dimensional (2-D) Poisson equation, including the

Transition-metal oxide perovskites usually exhibit mixed ionic and electronic conductivity and have been widely investigated as electrode materials for use in solid-oxide fuel cells. Recently, samarium nickelate SmNiO3 was found experimentally to show promising potential for use in proton-conducting fuel cells. To understand the ionic conductivity of SmNiO3, the oxygen and proton diffusion therein

For continued scaling with silicon, the stacked nanosheet field-effect transistor (SNSH-FET) is considered to be a major candidate for sub-7-nm technology. The radiofrequency (RF)/analog performance of a three-channel SNSH-FET is studied herein and benchmarked against a fin-shaped field-effect transistor (FinFET) at 7-nm technology and having the same footprint on the wafer. In the existing SNSH-FET

A new technique called series-connected dynamic node-driven transistor domino logic (SCDNDTDL) is proposed for the design of circuits with high speed and low power consumption in fin-shaped field-effect transistor (FinFET) technology. HSPICE is used to simulate 2-, 4-, 8-, and 16-input domino OR gates in complementary metal–oxide–semiconductor (CMOS) and FinFET technology using the 32-nm Predictive

The influence of incorporating HfO2 as a dielectric at the drain side and a silicon stack at the source side on the electrical performance of a double-gate tunnel field-effect transistor (TFET) is investigated by comparing a conventional TFET structure with four other structures in which the gate dielectric material is either homogeneous or heterogeneous while the insulator on the drain side is either

A simple physics-based three-dimensional (3-D) analytical model for AlInSb/AlSb/InSb double-gate high-electron-mobility transistors (DG-HEMTs) is presented. The model accurately predicts the short-channel effects (SCEs) in the channel region for various device dimensions, viz. channel length and width, by solving the three-dimensional Poisson equation. The effects of the barrier layer (AlInSb) thickness

Grover’s quantum search algorithm is a highly studied quantum algorithm that has potential applications in unstructured data search, achieving quadratic speedup over existing classical search algorithms. In this work, we propose a modified quantum circuit for multi-pattern quantum Grover’s search algorithm. Our proposed modification simplifies the conventional Grover’s algorithm circuit and makes it

We present a two-dimensional (2-D) analytical modeling of the surface potential of a double-gate vertical t-shaped tunnel field-effect transistor (TFET), considering the inherit dual modulation effect in such devices. This effect explains the control of the surface potential by both bias voltages, which are used to calculate the tunneling depletion width at the source and drain junctions. A model of

A numerical framework for DC and RF small-signal simulations of nanowire transistors is presented, which is based on the self-consistent solution of the Poisson, Schrödinger, and Boltzmann transport equations and is stable for the entire range from weak to strong particle scattering. The proposed approach does not suffer from the deficiencies due to the transformation of the Boltzmann transport equation

In partitioning, a circuit is recursively divided into several subcircuits so that each can be efficiently and independently designed with the main objective of reducing the cut-cost. Partitioning is a first step in the very large-scale integration (VLSI) physical design process, and all the other physical design steps such as floorplanning, placement, pin assignment, and routing depend on its outcome

Abstract The end groups of small-molecule acceptors strongly affect their properties and performance. In this study, theoretical analysis is performed to determine the reason why two similar molecules differing in their end group show very different performance in organic solar cells. The 1,1-dicyanomethylene-3-indanone-based small-molecule acceptor (DC-IDT2Tz) shows a higher transition dipole moment

The double-gate tunneling field-effect transistor (DGTFET) is investigated with two channel lengths (50 and 20 nm), along with the effect of the variation of the device design on its overall direct-current (DC) and radiofrequency (RF) performance. The studied design parameters are the drain doping abruptness (or spread) and its shift relative to the gate electrode. Additionally, the gate work function

The memristor was introduced as a nonlinear circuit element in 1971, and systems showing memristor-like properties such as zero-crossing hysteresis loops were described in 1976. In 2008, a thin-film system that behaved like a memristor over some part of its operating region was discovered. Memristors and memristive systems have thus become a hot research area in recent years, making it important to

Copper and copper-compound vapor lasers are most powerful in the visible spectrum with output power over 100 W. They offer unique properties including a laser beam with high coherence and convergence and high average output powers with relatively small dimensions. Recently, these lasers, and in particular the copper bromide (CuBr) laser, have been widely used as radiation sources and vapor brightness

The performance of organic cells based on bulk heterojunctions (BHJs) has improved recently, but further improvements are necessary. In this work, we have carried out a thorough examination using density functional theory (DFT) and time-dependent (TD)-DFT to investigate the structural and optoelectronic properties of pentacene-based organic molecules (PbOMs) as potential donor material for organic

In recent years, investigating organic compounds for Dye Sensitized Solar Cells (DSSCs) applications has received particular attention for its interesting optoelectronics properties. In this article, we have conducted a theoretical study on a series of D–π–A molecules, which have carbazole as a donor (D) and cyanoacrylic acid as acceptor (A) linked by a conjugated bridge. Theoretical calculations were

The structural, electronic, optical, and thermodynamic properties of hydrogenated silicene (silicane) in three stable structures, viz. chair (C), boat (B), and tricycle (T), are studied using first-principles calculations. The band structure and density of states are discussed. The stability is analyzed using binding energy and phonon calculations. Silicane is highly temperature sensitive compared

Two modifications of the molecular structures of Aurantinidin and Betanidin dyes were modeled, and the optical and electrical properties were calculated by using density functional theory (DFT) and time-dependent DFT (TD–DFT). The modification of the structures was done by connecting the units through vinyl groups and using regular electron acceptor and electron donor moieties to the original structures

A two-dimensional (2-D) technology computer-aided design (TCAD)-based simulation study of the back bias in the ultrathin silicon-on-insulator (SOI) tunnel field-effect transistor (TFET) is presented. The transfer characteristics of a conventional TFET called the back-bias TFET (BB-TFET) depend on the back bias and the oxide thickness below the TFET epitaxial layer. The back bias affects the electric

Transition metal oxides (TMOs) as passivating carrier-selective contact layers are investigated for silicon heterojunction solar cells. MoOx as hole-selective layer and TiOx as an electron-selective layer are explored in detail to design a high-efficiency silicon heterojunction solar cell without any specified surface passivation layer. The thickness and optical transparency of the MoOx hole-selective

A circularly polarized semicylindrical patch antenna loaded with unequal slots for use in S-band applications is presented and designed. Circular polarization operation is demonstrated for both planar and semicylindrical structures by embedding four quarter-circular slots with asymmetric radius at the four corners and two symmetric semicircular slots on both side edges. An axial ratio (AR) bandwidth

The role played by ion channel noise and ion shot noise around the threshold conditions for spiking activity in biological membranes is studied by means of a stochastic model based on the Hodgkin–Huxley equations, considering membrane voltage-dependent gating channels for sodium and potassium cations, and leakage channels. Ion channel noise, that is, the noise linked to the random opening and closing

The gravitational search algorithm (GSA) is a novel optimization technique that relies upon the law of motion and law of gravity of masses to describe the interaction between the agents. The GSA has shown outstanding performance but suffers from the drawback of a slow process due to the dependence of the fitness function on the masses of the agents. As a result, after each iteration, the masses get

We present a detailed study on the n-channel single-gate junctionless transistor (JLT) at the \({10}-\hbox{nm}\) node. We investigate the influence of its structural parameters on the on-state current and the off-state leakage current. Furthermore, we show that the use of high-k spacers may not be advantageous in future nanoscale junctionless transistors and confirm this argument by simulation. We

In this paper, statistical analysis of the static impact of charge traps on the drain current of p-type metal–oxide–semiconductor field-effect transistors is presented. The study was carried out by employing a 3-D particle-based Monte Carlo device simulator, which is capable of accounting for the interplay between charge traps and the random dopant fluctuation effect. It was observed that the impact

Three techniques are applied for the resolution of the time-domain electric field integral equation (TD-EFIE) for a thin wire antenna based on the well-known time-domain method of moments. Three temporal bases are used to approximate the unknown temporal variation. The first is derived from Dirac functions, the second from B-spline functions, and the third from Laguerre functions. Piecewise triangular

Slot waveguides based on silicon-on-insulator dielectric material are investigated theoretically for structural optimization with the aim of attaining the maximum light confinement with the minimum mode footprint inside the slot region. The effects of various geometrical parameters on the field confinement factor and effective mode area are examined to determine the performance of dielectric vertical-

The performance of the proposed depletion-type β-Ga2O3 negative-capacitance field-effect transistor (NCFET) having stacked ferroelectric HfO2 and Al2O3 gate dielectrics is investigated to determine its utility for radiofrequency (RF) applications. The results obtained for the RF performance of the proposed device are analyzed and compared with those of an experimentally demonstrated β-Ga2O3 metal–oxide–semiconductor

The terahertz (THz) gap lying between the microwave and optical parts of the electromagnetic spectrum has attracted immense attention due to its applications between radiofrequency (RF)/microwave and photonic systems. A structure consisting of a graphene sheet sandwiched between two graphene disks is introduced herein to control the reflection, absorption, and transmission of THz waves. The proposed

The Vivaldi antenna is developed as an ultra-wideband antenna with a directive pattern and high gain, which is attractive for radar application and microwave sensing. We have modeled various kinds of Vivaldi antenna and attempted to achieve linear or constant phase center. We realized that the phase center can be controlled by controlling the distribution of fields in level and around the antenna leading

A device simulator for p-MOSFETs, based on the Monte Carlo method for the solution of the Boltzmann transport equation, was developed, and results and implementation challenges are presented and discussed in detail in this paper. By using a Monte Carlo device simulator (MCDS), it is possible to consider effects that affect state-of-the-art devices that cannot be adequately considered using other methods

With the application of heterogeneous integration and advanced packaging technologies, the use of through-silicon vias (TSVs) to deliver the power supply has become popular in the design of stacked chips in three-dimensional integrated circuits. High-density vertical interconnections offer higher speed and bandwidth, but the electromagnetic coupling effect among TSVs becomes more serious. Therefore

We consider the large-signal equivalent circuit of a field-effect transistor (FET) with characteristics and parameters calculated using a two-dimensional (2D) quasi-hydrodynamic model while taking into account the electron velocity overshoot. In accordance with this equivalent circuit when applied to an AlGaN/GaN high-electron-mobility transistor (HEMT), the avalanche current (in the feedback branch)

In this paper, four different equivalent circuit models to describe substrate loading effect in GaN HEMT on Si substrate are investigated. The effect is characterized by Z-parameter measurements of open de-embedding structure for 16 × 200-μm GaN HEMT on Si substrate. The grey wolf optimization (GWO)-based procedure is developed to extract optimal values for the model elements. The performance of the

Versatile multilayer designs based on a transparent conductive oxide (TCO)/metal/TCO structure are proposed to overcome the trade-off between their electrical and optical properties. The overall performance of the investigated multilayer designs based on ZnO/metal/ZnO and indium tin oxide (ITO)/metal/ITO structures is compared based on their Haacke figure of merit (FoM) at λ = 550 nm. The influence

A novel structure for a THz absorber covering the THz band (0.1–10 THz) is presented. Exploiting nanographene disks and ribbons beside the dual-bias method, three modes of operation are introduced with the graphene gate biasing as the control parameter. The structure includes two layers consisting of graphene patterns on TOPAS dielectric and a thick gold plate at the bottom. The superior performance

Quantum dot cellular automata (QCA) constitute an emergent nanoscale-based digital nanoelectronics technology with comprehensive applications in nanocomputing based on the small nanometer size of such circuits and their ultralow power consumption, fast operation, and high clock frequency in comparison with transistor-based complementary metal–oxide–semiconductor (CMOS) technologies. A novel design

The positions of the upper edge of the valence band and the lower edge of the conduction band of semiconducting materials such as TiO2 are closely related to the values of the respective oxidation or reduction potentials. The modifications suffered by a material of this type impact on the displacements of the aforementioned bands and thus on the redox potentials. In the present work, anatase and rutile

The Boltzmann transport equation is commonly considered to be the best semi-classical description of carrier transport in semiconductors, providing precise information about the distribution of carriers with respect to time (one dimension), location (three dimensions), and momentum (three dimensions). However, numerical solutions for the seven-dimensional carrier distribution functions are very demanding

Local modulation of temperature has emerged as a new mechanism for regulation of molecular transport through nanopores. Predicting the effect of such modulations on nanopore transport requires simulation protocols capable of reproducing non-uniform temperature gradients observed in experiment. Conventional molecular dynamics (MD) method typically employs a single thermostat for maintaining a uniform

In this paper, we present a computational model to describe the electrical response of a constricted graphene nanoribbon (GNR) to biomolecules translocating through a nanopore. For this purpose, we use a self-consistent 3D Poisson equation solver coupled with an accurate three-orbital tight-binding model to assess the ability for a gate electrode to modulate both the carrier concentration as well as

Ion channels are part of nature's solution for regulating biological environments. Every ion channel consists of a chain of amino acids carrying a strong and sharply varying permanent charge, folded in such a way that it creates a nanoscopic aqueous pore spanning the otherwise mostly impermeable membranes of biological cells. These naturally occurring proteins are particularly interesting to device

The electronic structure and dielectric screening of finite-length armchair carbon nanotubes are studied with both tight-binding and ab initio methods. Good agreement is found in the band gap oscillation patterns and dielectric constants, which validates the tight-binding method as a reliable and fast approach to describe the screening effect of carbon nanotubes. For an illustration, our method is

The present work establishes a unique framework for the simulation study of ion-motive pumps in general and the Na(+)/K(+)-ATPase, or sodium pump, in particular. We shall discuss the implications of electrostatic analysis, valence calculations, and protein cavity data, each carried over data extracted from molecular dynamics simulations, on the structure-function relationship of Na(+)/K(+)-ATPase.

We outline the basic operational, structural and functional features of ion motive ATPases: transmembrane proteins central to biological functions of all animal cells. As an example we discuss the modeling problems associated with the operation of the surface membrane Na(+),K(+)-ATPase and skeletal muscle sarcoplasmic reticulum Ca(2+)-ATPase and focus on the frameworks required for their solution.