Search

Unlike any other nanoparticles known to date, magnetoelectric nanoparticles (MENPs) can generate relatively strong electric fields locally via the application of magnetic fields and, vice versa, have their magnetization change in response to an electric field from the microenvironment. Hence, MENPs can serve as a wireless two-way interface between man-made devices and physiological systems at the molecular level. With the recent development of room-temperature biocompatible MENPs, a number of novel potential medical applications have emerged. These applications include wireless brain stimulation and mapping/recording of neural activity in real-time, targeted delivery across the blood-brain barrier (BBB), tissue regeneration, high-specificity cancer cures, molecular-level rapid diagnostics, and others. Several independent in vivo studies, using mice and nonhuman primates models, demonstrated the capability to deliver MENPs in the brain across the BBB via intravenous injection or, alternatively, bypassing the BBB via intranasal inhalation of the nanoparticles. Wireless deep brain stimulation with MENPs was demonstrated both in vitro and in vivo in different rodents models by several independent groups. High-specificity cancer treatment methods as well as tissue regeneration approaches with MENPs were proposed and demonstrated in in vitro models. A number of in vitro and in vivo studies were dedicated to understand the underlying mechanisms of MENPs-based high-specificity targeted drug delivery via application of d.c. and a.c. magnetic fields. This article is categorized under: Nanotechnology Approaches to BiologyNanoscale Systems in Biology Therapeutic Approaches and Drug DiscoveryNanomedicine for Neurological Disease Therapeutic Approaches and Drug DiscoveryNanomedicine for Oncologic Disease Therapeutic Approaches and Drug DiscoveryEmerging Technologies.

This present work is an extensive effort to report the key role of indispensable technical challenges in the sensing performance of an embedded nanogap SiGe source dielectric-modulated tunnel field effect transistor (SGS-DM-TFET) biosensor during the conjugation of biological samples for the first time. In order to reach high and brilliant insights into the different design considerations impacting on the sensing performance of the biosensor under the study, two key issues in terms of process-related issue and real-time-related issues covering biomolecules manners in the nanogap cavity of the biosensor have been comprehensively studied through extensive numerical simulation. Investigations in this work revealed that the SGS-DM-TFET biosensor must be truly configured for working in realistic conditions. The obtained results give us a useful guideline for sensing the biomolecules samples in the real conditions including low coverage percentage of biological samples, charge effect, and discrete probe position with the help of SGS-DM-TFET biosensor while keeping the high sensitivity.

In this study, a junctionless double-gate metal-oxide semiconductor field-effect transistor (MOSFET) is investigated by using the concept of charge plasma. The n+ charge plasma in source and drain regions is created electrically in the double-gate MOSFET (CPSD-MOSFET) using additional appropriate metals without applying doping. The results showed that the structure is like a conventional MOSFET, which can improve some electrical parameters. It protects the proposed structure from some limitations such as random doping oscillations and short-channel effects bearing its conventional structure. In addition, high temperature and annealing processes are unnecessary for making the source/drain doping of the CPSD-MOSFET because their regions are created electrically. Thus, the thermal budget step is removed. Furthermore, the proposed structure has some improvements as compared to the junctionless transistor structure, and it can overcome the main problem of this structure, namely the high off current. In general, in the proposed structure, the charge plasma idea changes the charges and depletion regions besides the channel and improves the short-channel effects such as hot electron effect and leakage current because of the improved electric field.

We propose herein a new dual-gate metal---oxide---semiconductor field-effect transistor (MOSFET) with just a unipolar junction (UJ-DG MOSFET) on the source side. The UJ-DG MOSFET structure is constructed from an $${N}^{+}$$N+ region on the source side with the rest consisting of a $${P}^{-}$$P- region over the gate and drain, forming an auxiliary gate over the drain region with appropriate length and work function (named A-gate), converting the drain to an $${N}^{+}$$N+ region. The new structure behaves as a MOSFET, exhibiting better efficiency than the conventional double-gate MOSFET (C-DG MOSFET) thanks to the modified electric field. The amended electric field offers advantages including improved electrical characteristics, reliability, leakage current, $${I}_{\mathrm{ON}}/I_{\mathrm{OFF}}$$ION/IOFF ratio, gate-induced drain leakage, and electron temperature. Two-dimensional analytical models of the surface potential and electric field over the channel and drain are applied to investigate the drain current in the UJ-DG MOSFET. To confirm their accuracy, the MOSFET characteristics obtained using the 2D Atlas simulator for the UJ-DG and C-DG are analyzed and compared.

This paper suggests and investigates a double-gate (DG) MOSFET, which emulates tunnel field effect transistors (M-TFET). We have combined this novel concept into a double-gate MOSFET, which behaves as a tunneling field effect transistor by work function engineering. In the proposed structure, in addition to the main gate, we utilize another gate over the source region with zero applied voltage and a proper work function to convert the source region from N+ to P+. We check the impact obtained by varying the source gate work function and source doping on the device parameters. The simulation results of the M-TFET indicate that it is a suitable case for a switching performance. Also, we present a two-dimensional analytic potential model of the proposed structure by solving the Poisson’s equation in x and y directions and by derivatives from the potential profile; thus, the electric field is achieved. To validate our present model, we use the SILVACO ATLAS device simulator. The analytical results have been compared with it.

A Double-Gate Armchair-Graphene Nanoribbon FET is proposed to realize a high-sensitive and small-size biosensor in order to detect DNA without high-cost and time-consuming labeling process. Two nanogap cavities open inside the top and bottom gate oxides by the method of sacrificed layer etching. When the DNA biomolecule is introduced to the nanogap cavity, the hybridization event which is actually the formation of a double-strand of DNA will occur thus electrically modulating the GNR channel leading to a change in the drain current. The important report of this research is about attained high sensitivity of the proposed biosensor for a vast spectrum of the DNA biological samples. It is worth noting that a DNA sequence by 23 nucleotides extracted from Neisseria gonorrhoeae can be detected as a special case. An extensive numerical approach has been applied in order to characterize the proposed biosensor. The suggested biosensor has been evaluated by solving Schrodinger equation )SE( with Non-Equilibrium Green Function (NEGF) method in the mode-space coupled into Poisson solver in a self-consistent manner assuming ballistic limit. Two different expressions of sensitivity in terms of the threshold voltage and current have been defined giving a good metric for the sensitivity analysis. The results revealed a relative sensitivity of 1 mV/nm2 by a filled area by the DNA about 120 nm2 showing the excellent superiority for the proposed biosensor as compared to other counterparts. The effective area of the proposed biosensor obtains 240 nm2 which is very small in comparison with other reports highlighting high capability of the biosensor in the detection. It has been shown that the proposed biosensor can be implemented in ultra-scaling domain resulting in considerable increase in the sensitivity promising a potent and reliable candidate for high-sensitive and small-size biosensors. Also, the technical issues on designing the suggested biosensor have been investigated to achieve a useful guideline in detection and identification of the target DNAs.

We describe herein a 4H-SiC metal---semiconductor field-effect transistor (MESFET) with a novel dual well in the buffer layer. The key idea is to change the channel thickness to decrease the hole concentration and modify the depletion region shape and drain current path in the channel. In the proposed structure, a dual well is created in the buffer layer exactly under the gate. We call this structure the dual-well MESFET (DW-MESFET). The drain current of the proposed structure increases by 34.7 % compared with the conventional structure (C-MESFET) due to the change in channel thickness and modification of the depletion region and drain current path. Also, the maximum power density ($$P_{\mathrm{max}}$$Pmax) and the direct-current (DC) transconductance ($$g_{\mathrm{m}}$$gm) of the DW-MESFET increase by 45.23 and 72.5 %, respectively, in comparison with the C-MESFET structure. Hence, the proposed structure can be used for high-current and high-power applications.

Neural interfaces bridge the nervous system and the outside world by recording and stimulating neurons. Combining electrical and optical modalities in a single, hybrid neural interface system could lead to complementary and powerful new ways to explore the brain. This convergent approach has gained robust and exciting momentum recently in neuroscience and neural engineering research. Here, we review developments in the past several years aiming to achieve such hybrid electrical and optical microsystem platforms. Specifically, we cover three major categories of technological advances: transparent neuroelectrodes, optical neural fibers with electrodes, and neural probes/grids integrating electrodes and microscale light-emitting diodes. We analyze examples of these probes tailored to combine electrophysiological recording with optical imaging or optical stimulation of the brain and discuss possible directions of future innovation.

Effective and efficient management of human betacoronavirus severe acute respiratory syndrome (SARS)-CoV-2 virus infection i.e., COVID-19 pandemic, required sensitive and selective sensors with short sample-to-result durations for performing desired diagnostics. In this direction, one appropriate alternative approach to detect SARS-CoV-2 virus protein at low level i.e., femtomolar (fM) is exploring plasmonic metasensor technology for COVID-19 diagnostics, which offers exquisite opportunities in advanced healthcare programs, and modern clinical diagnostics. The intrinsic merits of plasmonic metasensors stem from their capability to squeeze electromagnetic fields, simultaneously in frequency, time, and space. However, the detection of low-molecular weight biomolecules at low densities is a typical drawback of conventional metasensors that has recently been addressed using toroidal metasurface technology. This research is focused on the fabrication of a miniaturized plasmonic immunosensor based on toroidal electrodynamics concept that can sustain robustly confined plasmonic modes with ultranarrow lineshapes in the terahertz (THz) frequencies. By exciting toroidal dipole mode using our quasi-infinite metasurface and a judiciously optimized protocol based on functionalized gold nanoparticles (AuNPs) conjugated with the specific monoclonal antibody specific to spike protein (S1) of SARS-CoV-2 virus onto the metasurface, the resonance shifts for diverse concentrations of the spike protein are monitored. Possessing molecular weight around ~76 kDa allowed to detect the presence of SARS-CoV-2 virus protein with significantly low as limit of detection (LoD) was achieved as ~4.2 fM. We envisage that outcomes of this research will pave the way toward the use of toroidal metasensors as practical technologies for rapid and precise screening of SARS‐CoV‐2 virus carriers, symptomatic or asymptomatic, and spike proteins in hospitals, clinics, laboratories, and site of infection., Highlights • Terahertz plasmonic metasensors for the detection of SARS-CoV-2 clinical diagnosis. • Quantitative and qualitative detection of spike proteins. • Rapid and precise detection of SARS-CoV-2 spike proteins at femtomolar concentrations. • Simple detection approach and compatible for high throughput COVID-19 screening in hospitals and test laboratories. • Early-stage detection of the infection through noninvasive tests.

In this work, a novel protocol is proposed for bidirectional controlled quantum teleportation (BCQT) in which a quantum channel is used with the eight-qubit entangled state. Using the protocol, two users can teleport an arbitrary entangled state and a pure two-qubit state (QBS) to each other simultaneously under the permission of a third party in the role of controller. This protocol is based on the controlled-not operation, appropriate single-qubit (SIQ) UOs and SIQ measurements in the Z and X-basis. Reduction of the predictability of the controller's qubit (QB) by the eavesdropper and also, an increasing degree of freedom of controller for controlling one of the users or both are other features of this protocol. Then, the proposed protocol is investigated in two typical noisy channels include the amplitude-damping noise (ADN) and the phase-damping noise (PDN). And finally, analysis of the protocol shows that it only depends on the amplitude of the initial state and the decoherence noisy rate (DR).

In this paper, a novel symmetrical structure (SS) of 4H---SiC metal semiconductor field effect transistor (MESFET) as an effective way to improve the breakdown voltage is presented. The key idea in this work is to improve the breakdown voltage, maximum output power density, and frequency parameters of the device using a symmetrical structure with recessed gate. The SS-MESFET modifies the electric field in the drift layer significantly. The influence of the SS-MESFET on the saturation current, breakdown voltage $$(\hbox {V}_{\mathrm{BR}})$$(VBR), and small-signal characteristics of the SS-MESFET are studied by numerical device simulation. Using two-dimensional device simulation, we demonstrate that the breakdown voltage $$(\hbox {V}_{\mathrm{BR}})$$(VBR) improved by factors 2.5 and 3.3 in comparison with an asymmetrical conventional MESFET structure (AC-MESFET) and a symmetrical conventional MESFET structure (SC-MESFET), respectively. Also, the maximum output power density $$(\hbox {P}_{\mathrm{max}})$$(Pmax) improved about by 93 and 250 % in comparison with the AC-MESFET and SC-MESFET structures, respectively. So, the SS-MESFET shows the superior maximum available gain (MAG), unilateral power gain (U), and current gain $$(\hbox {h}_{12})$$(h12) which is presenting the proposed structure is more suitable device for high power microwave applications.

In this brief, we present a new silicon-on-insulator MESFET by using an SiGe region as a well for absorbing the holes which are generated in result of the impact ionization mechanism. The key idea in this brief is to improve the breakdown voltage and self-heating effect (SHE) by utilizing an SiGe region to decreasing the crowding of holes around the source. The well is located in the buried oxide under the channel region. Simulation results show two extra peaks created on the electric field distribution that improves the breakdown voltage. Also, the floating body effect improves due to absorbing the holes by the hole's well and the lattice temperature decreases, so the SHE improves, too.

A novel SOI MESFET with high frequency performance over conventional structures is presented. The key idea in this work is to control gate capacitances by modifying channel charges. The proposed structure consists of an additional oxide layer in the channel under gate to control the channel charges. We investigate the improvement in device performance with two-dimensional and two-carrier device simulation. The proposed structure improves the gate-source and gate-drain capacitances and the minimum noise figure in comparison with a conventional SOI MESFET (C-SOI). Moreover, it has been decreased the carriers concentrations especially holes around drain. Hence it causes the generation rate decreases by 137% near the source side with a minimum value around the oxide and therefore the break down voltage will increase. The results demonstrate that the proposed structure has better frequency characteristics in comparison with the C-SOI structure.