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The quality of the SiO2/4H-SiC interface is critical for enhancing the performance of 4H-SiC metal–oxide–semiconductor field effect transistor devices. This research primarily concentrates on characterizing near-interface traps (NITs) in the SiO2/4H-SiC metal–oxide–semiconductor (MOS) capacitor using transient capacitance (C–t) measurements. Two types of samples were analyzed: thermally oxidized SiO2/4H-SiC MOS capacitors with (sample OX) and without (sample NO) NO post-oxidation annealing. It was found that the measurement voltage in C–t measurements significantly affects the electrical response of NITs, which has not received substantial attention in previous reports. By carefully selecting the measurement voltage, the maximum distance that carriers can tunnel into SiO2 from 4H-SiC can be assessed. Under the stress condition of maintaining a gate voltage of 20 V for 100 s, the maximum tunneling distances were determined to be 1.6 nm for sample OX and 1.4 nm for sample NO. Additionally, the concentrations of active NITs in both samples were examined. The results provide direct evidence that NO annealing significantly reduces active NITs, particularly those located farther from the interface. [ABSTRACT FROM AUTHOR]

We investigate the MX2 (M = {Hf, Zr}, X = {S, Se}) transition metal dichalcogenides patterned into armchair (AC) and zigzag (ZZ) nanoribbons (NRs) as potential channel materials in future logic field-effect devices. Ab initio quantum transport simulations are employed to assess the electronic, transport, and ballistic field-effect transistor (FET) properties of devices with such quasi-one-dimensional channels. We report a non-monotonic scaling behavior of MX2NR properties due to strong quantum confinement effects, which is reflected in a strong dependence of the ON-state current (ION) of MX2NR FETs on the nanoribbon configuration. The ∼2 nm-wide HfSe2 and ZrSe2 AC-PFETs have the highest ION of up to 2.6 mA/μm at 10 nA/μm OFF-state current. Surprisingly, MX2NR ZZ-NFETs exhibit a current increase of up to 70% when channel width is scaled down, with ION reaching 2.2 mA/μm in ∼2 nm-wide devices. The high ON-state performance is a direct consequence of high carrier injection velocity, which is explained by analyzing the band structure, transmission, and density of states. We demonstrate that nanostructured MX2 materials can be promising candidates for future logic transistors based on multi-nanowire architectures. [ABSTRACT FROM AUTHOR]

Large Schottky barriers formed at the interfaces between graphene and 2D semiconductors often degrade device performance. Here, taking the Janus MoSO as a prototype and using the first-principles calculations together with the band unfolding technique, we demonstrate that the Ohmic contact (OC), which is absent in pristine graphene/MoXY (X/Y = S, Se, Te. X ≠ Y), is realized in the pristine graphene/MoSO (G/MoSO) heterostructure. G/OMoS shows the n -type OC (OC- n) that leads to the p -doping of the graphene layer with a hole density of 1.17 × 10 13 /cm 2 , while G/SMoO exhibits the p -type Schottky contact with a tunable Schottky barrier height. The realization of OC and the interface dependent contact type are mainly attributed to the large intrinsic dipole between asymmetric S and O layers, which dominate the different behaviors of charge transfer and the associated interface dipole in heterostructures. Inspired by the finding, considering the larger dipole moment in Janus MoSeO and MoTeO, we further confirm that both OC- n and OC- p exist in pristine G/MoSeO and G/MoTeO. Moreover, on comparison with MoSO, both G/OMoS and G/SMoO show enhanced optical absorptions (∼ 10 5 cm − 1 ) in most of the visible light range. Our results not only show the potential application of G/MoSO in nanoelectronic devices such as field-effect transistors but also indicate that dipole engineering would help us to predict or design desirable electric contacts of Janus-transition metal dichalcogenide-based metal/semiconductor systems in advance. [ABSTRACT FROM AUTHOR]

In this contribution, we describe the various research domains in which RuII alkynyl derivatives are involved. Their peculiar molecular properties stem from a strong and intimate overlap between the metal centered d orbitals and the π system of the acetylide ligands, resulting in plethora of fascinating properties such as strong and tunable visible light absorption with a strong MLCT character essential for sensing, photovoltaics, light‐harvesting applications or non‐linear optical properties. Likewise, the d/π mixing results in tunable redox properties at low potential due to the raising of the HOMO level, and making those compounds particularly suited to achieve redox switching of various properties associated to the acetylide conjugated ligand, such as photochromism, luminescence or magnetism, for charge transport at the molecular level and in field effect transistor devices, or charge storage for memory devices. Altogether, we show in this review the potential of RuII acetylide compounds, insisting on the molecular design and suggesting further research developments for this class of organometallic dyes, including supramolecular chemistry. [ABSTRACT FROM AUTHOR]

Nowadays, silicon-based fin field-effect transistor (FinFET) devices have become the top choice for integrated circuit designers because they can handle the majority of application scenarios. In this article, the authors propose applying deep learning models to predict the electrical characteristics of devices using their structural parameters, aiming to solve the problems of complexity, time consumption, and convergence difficulty in traditional simulations. The authors first determine the electrical characteristics of simulations on FinFET devices using technology computer-aided design (TCAD). Different deep learning models were constructed in this study to predict various electrical parameters and characteristics of integrated circuit devices based on different datasets and prediction tasks, and high levels of accuracy were achieved. For instance, the average normalized mean square error of the predicted electrical parameters of FinFET devices based on TCAD simulation was less than 1.4 × 10−5, while the average relative errors of the predicted DC and AC characteristics of FinFET devices based on Berkeley short-channel insulated gate FET model (BSIM) simulation were 7.12 × 10−3 and 4.8 × 10−3, respectively. These results demonstrate that the proposed deep learning models can effectively predict the electrical parameters and characteristics of integrated circuit devices, providing strong support for device design and optimization. [ABSTRACT FROM AUTHOR]

Epitaxial graphene (EG) on cubic silicon carbide (3C-SiC) on silicon holds the promise of tunable nanoelectronic and nanophotonic devices, some uniquely unlocked by the graphene/cubic silicon carbide combination, directly integrated with the current well-established silicon technologies. Yet, the development of graphene field-effect devices based on the 3C-SiC/Si substrate system has been historically hindered by poor graphene quality and coverage, as well as substantial leakage issues of the heteroepitaxial system. We address these issues by growing EG on 3C-SiC on highly resistive silicon substrates using an alloy-mediated approach. In this work, we demonstrate a field-effect transistor based on EG/3C-SiC/Si with gate leakage current 6 orders of magnitude lower than the drain current at room temperature, which is a vast improvement on the current literature, opening the possibility for dynamically tunable nanoelectronic and nanophotonic devices on silicon at the wafer level. [ABSTRACT FROM AUTHOR]

Chemical sensors are increasingly used in healthcare because of their small size, durability, low resistance, and quick reaction time. This research aims to develop a pH biosensor utilizing an ion-sensitive field-effect transistor (ISFET) simulated with Silvaco technology computer-aided design (TCAD) software. The pH range of operation for the ISFET is 2 to 12. Sensitivity was evaluated based on the critical pH value and threshold voltage (Vth) parameters across different gate channel lengths (250 nm, 200 nm, and 50 nm) and sensing membrane thicknesses (3 nm, 10 nm, and 20 nm). The sensitivity of different materials to pH levels was measured. Titanium dioxide (TiO2) had the highest sensitivity at 57.98 mV/pH, followed by hafnium (IV) oxide (HfO2) at 57.46 mV/pH, tantalum pentoxide (Ta2O5) at 57.36 mV/pH, aluminium oxide (Al2O3) at 55.05 mV/pH, and silicon nitride (Si3N4) at 54.75 mV/pH. Notably, TiO2 with a 200 nm gate channel length and a 3 nm sensing membrane thickness demonstrated the highest sensitivity. These findings highlight the potential of ISFETs, particularly those with TiO2 sensing membranes, as robust and precise pH monitoring platforms in the biomedical industry. [ABSTRACT FROM AUTHOR]

Current diagnostic and prognostic tests for prostate cancer require specialised laboratories and have low specificity for prostate cancer detection. As such, recent advancements in electrochemical devices for point of care (PoC) prostate cancer detection have seen significant interest. Liquid-biopsy detection of relevant circulating and exosomal nucleic acid markers presents the potential for minimally invasive testing. In combination, electrochemical devices and circulating DNA and RNA detection present an innovative approach for novel prostate cancer diagnostics, potentially directly within the clinic. Recent research in electrochemical impedance spectroscopy, voltammetry, chronoamperometry and potentiometric sensing using field-effect transistors will be discussed. Evaluation of the PoC relevance of these techniques and their fulfilment of the WHO's REASSURED criteria for medical diagnostics is described. Further areas for exploration within electrochemical PoC testing and progression to clinical implementation for prostate cancer are assessed. [ABSTRACT FROM AUTHOR]

Understanding and improving the contact resistance of two-dimensional materials for the fabrication of next-generation devices is of vital importance to be able to fully utilize the new physics available in these materials. In this work, eight different contact metals (Ag, Au, Cr, Cu, In, Mo, Ni, and Ti) have been investigated using the same sample of monolayer MoS2. Through the fabrication and testing of multiple, identically sized field-effect transistor devices per contact metal, we compensate for large variability in electrical properties of as-grown chemical vapor deposition MoS2 and deduce the relative performance of each metal. The general trend of lower work function metals having lower contact resistance holds with In, Ag, and Ti performing the best of the metals tested. Our results are compatible with recent research suggesting that the contact resistance in undoped, monolayer MoS2 is dominated by a lateral junction resistance, and we provide context for how this manifests in device-to-device variation. Multiple orders of magnitude differences in contact resistance are observed between metals and can be explained by this lateral barrier operating in the thermionic-field emission regime. [ABSTRACT FROM AUTHOR]

This study developed a technology for a vertical field‐effect transistor (VFET) incorporating c‐axis aligned crystal oxide semiconductor on a Gen 3.5 glass substrate. VFETs, with a channel length of 0.5 μm, demonstrated stable characteristics with minimal variation, higher on‐state current compared with low‐temperature polysilicon FETs, and extremely low off‐state leakage current. A prototype 513‐ppi organic light‐emitting diode display that features a red, green, and blue stripe arrangement and includes an internal compensation circuit with a configuration of six transistors and two capacitors was fabricated by harnessing the advantageous features of VFETs. Such a display was previously unattainable with planar FETs. Thus, the developed VFET technology presents a viable pathway for achieving ultrahigh‐resolution panels on glass substrates. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials are attracting attention because of their outstanding physical, chemical, and electrical properties for applications of various future devices such as back-end-of-line field effect transistor (BEOL FET). Among many 2D materials, tin disulfide (SnS2) material is advantageous for low temperature process due to low melting point that can be used for flexible devices and back-end-of-line (BEOL) devices that require low processing temperature. However, low temperature synthesis method has a poor crystallinity for applying to various semiconductor industries. Hence, many studies of improving crystallinity of tin disulfide film are studied for enhancing the quality of film. In this work, we propose a precursor multi-dosing method before deposition of SnS2. This precursor pre-treatment was conducted by atomic layer deposition cycles for more adsorption of precursors to the substrate before deposition. The film quality was analyzed by x-ray diffraction, Raman, transmission electron microscopy, atomic force microscopy and x-ray photoelectron spectroscopy. As a result, more adsorbates by precursor pre-treatment induce higher growth rate and better crystallinity of film. [ABSTRACT FROM AUTHOR]

A WSe2 field effect transistor integrated with a lead zirconium titanate (PZT) pyroelectric device has been designed, fabricated, and tested and is described as the integrated pyroelectric device. The integrated device has been compared to a standalone pyroelectric device, which consists of PZT sandwiched between platinum electrodes. A pyroelectric coefficient of 1.755 × 10−4 C/m2K has been realized for our thin-film PZT (650 nm). The integrated device amplifies the output of the standalone device by over ten orders of magnitude as the current density calculated for the devices is 16 nA/mm2 and 1 nA/mm2, respectively. The interplay between the pyro- and ferro-induced polarization of the integrated device has been studied. From our observations, the ferroelectric gating controls directly the drain-source current output of the integrated device, showing anti-clockwise hysteresis behavior. The device shows promise for application in infrared sensing. [ABSTRACT FROM AUTHOR]

Purpose: High packaging density in the present VLSI era builds an acute power crisis, which limits the use of MOSFET device as a constituent block in CMOS technology. This leads researchers in looking for alternative devices, which can replace the MOSFET in CMOS VLSI logic design. In a quest for alternative devices, tunnel field effect transistor emerged as a potential alternative in recent times. The purpose of this study is to enhance the performances of the proposed device structure and make it compatible with circuit implementation. Finally, the performances of that circuit are compared with CMOS circuit and a comparative study is made to find the superiority of the proposed circuit with respect to conventional CMOS circuit. Design/methodology/approach: Silicon–germanium heterostructure is currently one of the most promising architectures for semiconductor devices such as tunnel field effect transistor. Analytical modeling is computed and programmed with MATLAB software. Two-dimensional device simulation is performed by using Silvaco TCAD (ATLAS). The modeled results are validated through the ATLAS simulation data. Therefore, an inverter circuit is implemented with the proposed device. The circuit is simulated with the Tanner EDA tool to evaluate its performances. Findings: The proposed optimized device geometry delivers exceptionally low OFF current (order of 10^−18 A/um), fairly high ON current (5x10^−5 A/um) and a steep subthreshold slope (20 mV/decade) followed by excellent ON–OFF current ratio (order of 10^13) compared to the similar kind of heterostructures. With a very low threshold voltage, even lesser than 0.1 V, the proposed device emerged as a good replacement of MOSFET in CMOS-like digital circuits. Hence, the device is implemented to construct a resistive inverter to study the circuit performances. The resistive inverter circuit is compared with a resistive CMOS inverter circuit. Both the circuit performances are analyzed and compared in terms of power dissipation, propagation delay and power-delay product. The outcomes of the experiments prove that the performance matrices of heterojunction Tunnel FET (HTFET)-based inverter are way ahead of that of CMOS-based inverter. Originality/value: Germanium–silicon HTFET with stack gate oxide is analytically modeled and optimized in terms of performance matrices. The device performances are appreciable in comparison with the device structures published in contemporary literature. CMOS-like resistive inverter circuit, implemented with this proposed device, performs well and outruns the circuit performances of the conventional CMOS circuit at 45-nm technological node. [ABSTRACT FROM AUTHOR]

Regioregular poly(3-hexylthio)thiopene (P3HTT) has emerged tremendous potential in organic electronic applications due to the strong noncovalent interactions from the sulfur atom linked to thiophene. However, P3HTT generally exhibits low charge mobility mostly due to poor solution processability attributed to dense arrangement of hexylthio side chain in polymer, which led to strong noncovalent interactions among sulfur atoms. To balance the nonvalent interaction and aggregation for P3HTT, herein, we systematically study the effect of hexylthio side chain content in polymer backbone on the structure and properties. A series of regioregular P3HTT-based homopolymers (P3HTT, P3HTT-50, P3HTT-33 and P3HTT-25) were prepared via Kumada catalyst transfer polycondensation method from a set of mono-, bi-, ter- and quarter-thiophenes containing different contents of hexylthio side chain. The DFT calculation shows the planarity of polymers backbone could be improved through reducing the density of hexylthio side chain in polymer mainchain. And significant changes in their crystallinity, aggregation and optical properties were observed with the content of hexylthio side chain reducing. The P3HTT-33 displayed the highest field-effect transistor hole mobility of 2.83×10−2 cm2·V−1·s−1 resulting from a balance between the crystallinity and planarity. This study demonstrates modulating the content of hexylthio side chain in P3HTT is an effective strategy to optimize the opto-electronic properties of polymer obtaining excellent semiconductor device performance. [ABSTRACT FROM AUTHOR]

The transport and noise properties of fabricated, high‐performance, gate‐all‐around silicon liquid‐gated nanowire field‐effect transistor devices are investigated in different concentrations of MgCl2 solutions. The critical concentration of MgCl2 solution for charge inversion at the solid‐liquid interface is verified using noise spectroscopy and confirmed using the capacitance‐voltage measurement technique. In this study, it is found that the Hooge parameter (αH) and the equivalent input noise (SU) can effectively reflect the ion behavior on the surface of the nanowire. Moreover, the noise curves for αH and SU indicate two turning points at concentrations of 10−4 and 10−1 m for a peak and a valley, respectively. The noise transformation is related to the behavior of ions near the solid‐liquid interface in solutions with different MgCl2 concentrations is revealed. The results show that noise spectroscopy is a powerful method for monitoring charge dynamic processes in the research field of biosensors. [ABSTRACT FROM AUTHOR]

This work implements three fast measurement techniques based on the measure–stress–measure (MSM) method. These techniques, namely, measuring–around– , one–point on–the–fly (OTF), and pulsed current-voltage (PIV), were used to characterize three different technologies of metal–oxide–semiconductor field-effect transistors (MOSFETs) with same gate dielectric silicon–dioxide (SiO2) and various thicknesses = 20 nm, 4 nm, 2.3 nm. Moreover, well–configured electrical stress biasing has been performed to discuss the dielectric degradation of these devices using those characterization techniques. The pros and cons of the used techniques are well discussed based on our results. Furthermore, experimental results showed that threshold voltage shift () follows a power law time dependence with time exponent (n) being 0.16 for molecular hydrogen (H2) diffusing species and 0.25 for hydrogen atoms (H) diffusing species. We have found that the thicker the SiO2 dielectric the more the oxide traps () contribute to the resulting degradation. However, the dependency between SiO2 dielectric thickness and oxide traps could not be necessarily linear. [ABSTRACT FROM AUTHOR]

Silanization is one of the widely explored surface modification strategies for biofunctionalization of oxide interfaces. For biosensor applications, silanes with active terminal groups such as amine, thiol, carboxylic, and aldehyde groups are utilized in routine. In near‐field sensing schemes like biologically sensitive field‐effect transistors, it is crucial to generate a homogeneous layer of silane to confine the biointeractions in close vicinity of the sensor interface. The homogeneity of such biofunctional layer is determined by the surface activation and silanization protocol being applied. Herein, the impact of the surface activation process and silanization on electrical characteristics of field‐effect devices is studied comprehensively using an electrolyte‐oxide‐semiconductor (EOS) capacitor with a high‐quality gate oxide. The thermally grown silicon oxide (SiO2) interface is activated using acidic mixtures and plasma treatment, while the subsequent silanization steps are investigated comparatively using two different silanes (3‐aminopropyl triethoxysilane (APTES) and 3‐glycidyloxypropyl trimethoxysilane (GPTMS) in wet‐chemical and vapor‐phase processes. Furthermore, the optimized silanization process is utilized to immobilize an oligo strand at the EOS capacitor surface, followed by the hybridization of complementary oligo strands. The optimized protocol holds the potential for large‐scale production of functional oxide interfaces for various applications. [ABSTRACT FROM AUTHOR]

The synthesis of bench‐stable conjugated π‐radicals is challenging owing to the lack of modular approaches, which greatly hampers their practical material screens and applications. Here, we demonstrate a spin‐distribution‐directed regioselective substitution strategy to introduce substituents into the specific positions of an olympicenyl radical in a stepwise manner, resulting in a series of highly stable radical species. The substituents can also adjust the crystal packing by means of steric and electronic factors, enabling the changing from a π‐dimer to a pseudo‐one‐dimensional chain. The first single crystal organic field‐effect transistor device based on a graphenic radical is fabricated in air, showing a hole mobility of up to 0.021 cm2 V−1 s−1 and excellent device stability. This approach may be generalized to diverse spin‐delocalized open‐shell organic radicals. [ABSTRACT FROM AUTHOR]

β-Ga2O3, with excellent bandgap, breakdown field, and thermal stability properties, is considered to be one of the most promising candidates for power devices including field-effect transistors (FETs) and for other applications such as Schottky barrier diodes (SBDs) and solar-blind ultraviolet photodetectors. Ohmic contact is one of the key steps in the β-Ga2O3 device fabrication process for power applications. Ohmic contact techniques have been developed in recent years, and they are summarized in this review. First, the basic theory of metal–semiconductor contact is introduced. After that, the representative literature related to Ohmic contact with β-Ga2O3 is summarized and analyzed, including the electrical properties, interface microstructure, Ohmic contact formation mechanism, and contact reliability. In addition, the promising alternative schemes, including novel annealing techniques and Au-free contact materials, which are compatible with the CMOS process, are discussed. This review will help our theoretical understanding of Ohmic contact in β-Ga2O3 devices as well as the development trends of Ohmic contact schemes. [ABSTRACT FROM AUTHOR]

A method is presented for scaling up the production of flakes of van der Waals materials via mechanical exfoliation. Using a roll‐to‐roll setup and an automatized, massive parallel exfoliation process, adhesive tapes with a high density of nanosheets of van der Waals materials are produced. The technique allows for obtaining a good trade‐off between large lateral size and excellent area scalability, while also maintaining low cost. The potential of the method is demonstrated through the successful fabrication of field effect transistors and flexible photodetectors in large batches. This low‐cost method to produce large area films out of mechanically exfoliated flakes is very general, and it can be applied to a variety of substrates and van der Waals materials and, moreover, it can be used to combine different van der Waals materials on top of each other. Therefore, it is believed that this production method opens an interesting avenue for fabrication of low‐cost devices while maintaining a good scalability and performance. [ABSTRACT FROM AUTHOR]

Featured with highly structural anisotropy, rhenium-based transition metal dichalcogenides (TMDs) and alloys have attracted significant attention in electronics, optoelectronics, energy storage, and catalysis. The controlled growth of large-area, high-quality anisotropic TMDs is critical for associated applications. However, the Jahn–Teller effect and Peierls distortion of the lattice easily induce out-of-plane growth, making it a challenge to prepare uniform-thickness Re-based TMDs. Here, we report a NaCl-assisted chemical vapor deposition strategy for Re-based TMDs and highlight the essential role of Na+ absorption based on a combination of experiments and density functional theory calculations. We found that Cl has little influence on the intermediate products during the reaction process, while Na is responsible for reducing the highest energy barrier required for the formation of Re–Re chains. The barrier for the rate-determining step is reduced by 0.325 eV compared to that without considering Na+ adsorption. Additionally, the field-effect transistor device based on the sodium-assisted synthesized ReS2 monolayer demonstrates superior electrical properties. Our findings not only provide a reliable experimental scheme for the preparation of Re-based semiconductors but also promote the application of ReS2 in high-performance electronics. [ABSTRACT FROM AUTHOR]

Electric‐field regulation of magnetic properties in perovskite manganites has attracted much attention for its potential in spintronics. For antiferromagnetic perovskite manganites, fewer studies are reported due to technological difficulties in probing their magnetic properties. Here, negative exchange bias (EB) is realized in epitaxial antiferromagnetic/ferromagnetic manganite bilayers with atomically flat interfaces. The low‐voltage pulse modulation of EB is demonstrated using the field‐effect device geometry with the ferroelectric copolymer, polyvinylidene fluoride with trifluoroethylene as a dielectric gating layer, antiferromagnetic La0.35Sr0.65MnO3 (AF‐LSMO) as pinning layer, and ferromagnetic La0.7Sr0.3MnO3 (FM‐LSMO) as conduction channel. Instead of using non‐volatile polarizations to control the EB, volatile polarizations in ferroelectric field effect transistors are suggested to be capable of modulating the EB. With high‐resolution electron microscopy and spectroscopy, the non‐volatile regulation of EB is attributed to the creation/annihilation of oxygen vacancies in the AF‐LSMO layer via low‐voltage pulses. This study reveals the effect of volatile electric polarizations in ferroelectric field effect devices and highlights the potential for low‐voltage pulse control of the physical properties in antiferromagnetic perovskite oxide insulators. [ABSTRACT FROM AUTHOR]

Universal platforms to analyze biomolecules using sensor devices can address critical diagnostic challenges. Sensor devices like electrical-based field-effect transistors play an essential role in sensing biomolecules by charge probing. Graphene-based devices are more suitable for these applications. It has been previously reported that Graphene Field-Effect Transistor (GFET) devices detect DNA hybridization, pH sensors, and protein molecules. Graphene became a promising material for electrical-based field-effect transistor devices in sensing biomarkers, including biomolecules and proteins. In the last decade, FET devices have detected biomolecules such as DNA molecules, pH, glucose, and protein. These studies have suggested that the reference electrode is placed externally and measures the transfer characteristics. However, the external probing method damages the samples, requiring safety measurements and a substantial amount of time. To control this problem, the graphene field-effect transistor (GFET) device is fabricated with an inbuilt gate that acts as a reference electrode to measure the biomolecules. Herein, the monolayer graphene is exfoliated, and the GFET is designed with an in-built gate to detect the Interleukin-6 (IL-6) protein. IL-6 is a multifunctional cytokine which plays a significant role in immune regulation and metabolism. Additionally, IL-6 subsidizes a variability of disease states, including many types of cancer development, and metastasis, progression, and increased levels of IL-6 are associated with a higher risk of cancer and can also serve as a prognostic marker for cancer. Here, the protein is desiccated on the GFET device and measured, and Dirac point shifting in the transfer characteristics systematically evaluates the device's performance. Our work yielded a conductive and electrical response with the IL-6 protein. This graphene-based transducer with an inbuilt gate gives a promising platform to enable low-cost, compact, facile, real-time, and sensitive amperometric sensors to detect IL-6. Targeting this pathway may help develop treatments for several other symptoms, such as neuromyelitis optica, uveitis, and, more recently, COVID-19 pneumonia. [ABSTRACT FROM AUTHOR]

In this study, we investigated the gas-sensing mechanism in bottom-gate organic field-effect transistors (OFETs) using poly(triarylamine) (PTAA). A comparison of different device architectures revealed that the top-contact structure exhibited superior gas-sensing performance in terms of field-effect mobility and sensitivity. The thickness of the active layer played a critical role in enhancing these parameters in the top-contact structure. Moreover, the distance and pathway for charge carriers to reach the active channel were found to significantly influence the gas response. Additionally, the surface treatment of the SiO2 dielectric with hydrophobic self-assembled mono-layers led to further improvement in the performance of the OFETs and gas sensors by effectively passivating the silanol groups. Under optimal conditions, our PTAA-based gas sensors achieved an exceptionally high response (>200%/ppm) towards NO2. These findings highlight the importance of device and interface engineering for optimizing gas-sensing properties in amorphous polymer semiconductors, offering valuable insights for the design of advanced gas sensors. [ABSTRACT FROM AUTHOR]

Ferroelectric (FE) control of magnetism at nanoscale, for instance, FE control of the polarity of spin‐polarized current is crucial for technological advances in magnetoelectric and spintronic applications. However, this fascinating functionality has not been reported in nanoscale systems yet. Herein, a new class of FE/A‐type antiferromagnetic heterobilayer/FE van der Waals (vdW) multiferroic structures is found, in which the FE control of polarity of spin‐polarized current is found possible. Take Sc2CO2/CrSiTe3/CrGeTe3/Sc2CO2 heterostructure as a successful example. First‐principles calculations reveal that its polarity of half‐metallicity can be switched by flipping the FE polarization orientation. Meanwhile, device transport simulation shows that its up/down spin current transmission ratio is as large as 0.1 × 103 at P→↑↑\[\mathop {\rm{P}}\limits^ \to \uparrow \uparrow \] Sc2CO2 configuration and is only 2.6 × 10−3 at P→↓↓$\mathop {\rm{P}}\limits^ \to \downarrow \downarrow $ Sc2CO2 configuration in the vdW multiferroic heterostructures. Essentially, it stems from the reversible FE switch of the internal electric field across the CrSiTe3/CrGeTe3 heterobilayer and the FE control of the interfacial effect between Sc2CO2 and Cr(Si/Ge)Te3 layers. This work opens a direction for constructing low‐energy‐dissipation, non‐volatile, and high‐sensitive spintronic devices such as spin field‐effect transistors. [ABSTRACT FROM AUTHOR]

The technology development, combined with chip size reductions, has significantly increased power density. Furthermore, the power limitation in portable devices has increased the importance of power consumption considerably. Approximate computing as an emerging paradigm leverages the error resiliency of applications to decrease power consumption. In this paper, we propose four approximate 4:2 compressors. We utilize the gate diffusion input to achieve significant area reduction in the proposed compressors. Afterward, we employ these compressors in the structure of Dadda multipliers. Compared to the state-of-the-art works, the proposed compressors result in, on average, 45% and 42% higher accuracy and lower area, respectively. Circuit simulations were carried out at a 32-nm carbon nanotube field-effect transistor technology node by HSPICE. The comparisons between our proposed compressors and exact compressor indicate that there has been an average improvement of 55%, 60% and 46% in the number of transistors, power consumption, and delay, respectively. In addition, the proposed multipliers were used in three image processing applications, including image multiplication, sharpening, and smoothing. The results show up to 46% and 70% improvement in the mean structure similarity index metric and peak signal-to-noise ratio compared to the state-of-the-art. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive investigation of the electrical properties of a heterojunction tunnel field effect transistor with enhanced electrical tunneling current. The proposed device structure incorporates an extended source region and two parallel channels positioned above and below the source region. This configuration effectively amplifies the tunneling area, leading to a significant improvement in the on-state current. Moreover, the inclusion of an embedded oxide region between the source and drain regions confers the device with a high resistance to short-channel effects. The combination of materials in both the source and channel region results in a staggered band alignment at the tunneling junction. This specific configuration leads to a lower threshold voltage for the initiation of tunneling. The impact of critical design parameters on the device performance has been thoroughly examined. A 2D variation matrix has been developed to compute the threshold voltage and on-state current variation based on the source doping density and gate workfunction, which serve as essential design parameters to optimize the electrical performance of the device. Furthermore, the device has achieved a unity current-ratio frequency of 300 GHz indicating its suitability for highfrequency applications. Additionally, the proposed structure provides an on-state current of 2.24×10-4 (A/µm), an offstate current of 1.24×10-15 (A/µm), an on/off current ratio of 1.81×1011, and a subthreshold swing of 5 (mV/dec). These characteristics make the device viable for energy-efficient, high-speed digital circuits. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) van der Waals (vdW) materials offer nearly defect-free strands as channel materials in the field-effect transistor devices and probably, a better interconnect than conventional copper with higher current density and resistance to electro-migration with sustainable down-scaling. We report a theoretically predicted halide based 1D few-chain atomic thread, PdBr2, isolable from its bulk which crystallizes in a monoclinic space group C2/c. Liquid phase exfoliated nanowires with mean length (20 ± 1)μm transferred onto a SiO2/Si wafer with a maximum aspect ratio (length:width) of ≈ 5000 confirm the lower cleavage energy perpendicular to the chain direction. Moreover, an isolated nanowire can also sustain a current density of 200 MA/cm2, which is atleast one-order higher than typical copper interconnects. However, local transport measurement via the conducting atomic force microscopy (CAFM) tip along the cross direction of the single chain records a much lower current density due to the anisotropic electronic band structure. While 1D nature of the nanoobject can be linked with a non-trivial collective quantum behavior, vdW nature could be beneficial for possible pathways in an interconnect fabrication strategy with better control of placement in an integrated circuit. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) van der Waals (vdW) materials offer nearly defect-free strands as channel materials in the field-effect transistor devices and probably, a better interconnect than conventional copper with higher current density and resistance to electro-migration with sustainable down-scaling. We report a theoretically predicted halide based 1D few-chain atomic thread, PdBr2, isolable from its bulk which crystallizes in a monoclinic space group C2/c. Liquid phase exfoliated nanowires with mean length (20 ± 1)μm transferred onto a SiO2/Si wafer with a maximum aspect ratio (length:width) of ≈ 5000 confirm the lower cleavage energy perpendicular to the chain direction. Moreover, an isolated nanowire can also sustain a current density of 200 MA/cm2, which is atleast one-order higher than typical copper interconnects. However, local transport measurement via the conducting atomic force microscopy (CAFM) tip along the cross direction of the single chain records a much lower current density due to the anisotropic electronic band structure. While 1D nature of the nanoobject can be linked with a non-trivial collective quantum behavior, vdW nature could be beneficial for possible pathways in an interconnect fabrication strategy with better control of placement in an integrated circuit. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT)‐based transistor devices have been demonstrated and are seen as the next‐generation alternative to replace the current generation electronic devices based on silicon MOS technology. Their limitations, however, are related to their instability in ambient conditions and technical challenges in scaling up production of individual CNT devices. Herein, a simple technique to convert ambipolar (both n‐ and p‐carrier) individual CNT‐based transistors into unipolar (p‐type carrier) transistors that carry large currents ≈±7 mA before saturation is demonstrated. Such large current‐carrying capability from an individual or single‐bundle CNTs will be ideal for applications that require high currents such as output stages of radio frequency (RF) and audio amplifiers. This work highlights the ability to tune CNT‐based transistor devices to suit specific applications, which is essential for the development of next generation of nanoelectronics. [ABSTRACT FROM AUTHOR]

The features of Nanotube Carbon (CNT) are fascinating to study due to their unique structural and electrical capabilities. The small structure of CNT in Field-Effect Transistor technology can produce a smaller device with a better performance. This work implemented the Taguchi method to optimize the Carbon Nanotube Field-Effect Transistor (CNTFET). The Minitab 19 software was used to carry out the Taguchi method analysis. Three design parameters (CNT’s diameter, pitch, and the number of CNT) with three sizes were chosen to improve the CNTFET capabilities. L27 orthogonal array and signal-to-noise (SNR) were used to collect and analyze the data. The result from the Taguchi method was validated using ANOVA. The analysis results displayed the best combination of the three design parameters that produced the optimum performance in terms of high-power and low-power application. The most dominant design parameter that affected the CNTFET’s current characteristics was the CNT diameter with 59.93%, 96.15% and 99.14% towards on-current (Ion), off-current (Ioff) and current ratio (Ion/Ioff), respectively. The device can be further optimized by identifying the most dominant structure in CNTFET. Eventually, the CNTFET devices can be enhanced in terms of high-power and low-power applications. [ABSTRACT FROM AUTHOR]

A detailed review of sub‐5 nm 2D semiconductor monolayer (ML) field‐effect transistors (FETs) is presented. A brief introduction to the fundamentals of 2D materials and their properties is provided followed by a critical review to propose an appropriate channel material from the available 2D materials. Various device simulation techniques incorporating density functional theory (DFT) and nonequilibrium Green's function (NEGF) are discussed in order to comprehend the distinctive features of 2D materials and the ballistic performance of sub‐5 nm ML 2D FETs. Relevant, recent experimental progress is also discussed. The review suggests that sub‐5 nm monolayer FETs based on 2D semiconductors like black phosphorene, WSe2N4, silicene, tellurene, arsenene, WSe2, MoTe2, MoS2, InSe, α‐CS, MoSi2N4, WS2, Bi2O2Se, GeSe, SnSe2, SnS2, AsP, GeS, MoSi2N4, BiH, SnSe2 and MoTe2 show excellent device performance meeting the International Technology Roadmap for Semiconductor (ITRS) requirements (2013 Version) for both high‐performance (HP) and low‐power (LP) applications in terms of on‐state current, subthreshold swing (SS), delay time, and power delay product (PDP). [ABSTRACT FROM AUTHOR]

Reconfigurable field‐effect transistors, capable of being dynamically programmed during run‐time, overcome the static nature of conventional complementary metal‐oxide semiconductors by reducing the transistor count and the circuit path delay. Thereby, SiGe and Ge are predicted to boost drive currents, switching speed and to reduce power consumption. Nevertheless, Ge‐based reconfigurable field‐effect transistor prototypes have so far fallen short in reaching both the promised performance due to interface instability to their contacts and gate oxides, as well as in reaching the current–voltage symmetry necessary for circuit applicability. Here, a top‐down fabricated SiGe‐based reconfigurable transistor technology is reported that is comprised of a vertical Si‐Si0.67Ge0.33 heterostructure enabling the envisioned high and symmetric on‐currents of both n‐ and p‐type operation. Monolithic integration with single‐elementary crystalline Al contacts alleviates process variability compared to conventional Ni‐silicide/Ni‐germanide contacts and introduces an ultra‐thin Si interlayer providing stability and equal injection efficiency of holes and electrons. The implementation of a three top‐gate transistor in combination with a hysteresis‐free Si/SiO2/HfO2 gate stack enhances polarity control and leakage current suppression to limit static power dissipation. Importantly, the obtained Al‐Si‐SiGe multi‐heterojunction and advanced reconfigurable transistor design is the first Ge‐based technology showing the envisioned stability and performance enhancements. [ABSTRACT FROM AUTHOR]

Creating a good contact between electrodes and graphene nanoribbons (GNRs) has been a long-standing challenge in searching for the next GNR-based nanoelectronics. This quest requires the controlled fabrication of sub-20 nm metallic gaps, a clean GNR transfer minimizing damage and organic contamination during the device fabrication, as well as work function matching to minimize the contact resistance. Here, we transfer 9-atom-wide armchair-edged GNRs (9-AGNRs) grown on Au(111)/mica substrates to pre-patterned platinum electrodes, yielding polymer-free 9-AGNR field-effect transistor devices. Our devices have a resistance in the range of 106–108 Ω in the low-bias regime, which is 2–4 orders of magnitude lower than previous reports. Density functional theory calculations combined with the non-equilibrium Green's function method explain the observed p-type electrical characteristics and further demonstrate that platinum gives strong coupling and higher transmission in comparison to other materials, such as graphene. [ABSTRACT FROM AUTHOR]

This paper summarizes the results of investigations of bipolar transistors made in VESTIC (Vertical Slit Transistor-based Integrated Circuits) technology. This technology was proposed by W. Maly as an alternative to classical bulk CMOS technology. However, the basic VESTIC cell can be used not only to make field effect transistors but also to make bipolar transistors. Their structures differ in many ways from existing structures of bipolar transistors. The investigations reported here aim to answer the question: can VESTIC-based lateral bipolar transistors be useful as active devices, and can they be made technologically compatible with field effect VESTIC devices? The theoretical studies were followed by the fabrication and measurements of VESTIC-based p-n-p and n-p-n bipolar devices. Although the manufacturing technology available was far from optimal, working bipolar devices were obtained. The results show that VESTIC-based bipolar devices may achieve acceptable parameters if made with state-of-the-art manufacturing technology. The main outcome of the research reported in the paper is that p-n-p and n-p-n bipolar transistors with acceptable parameters may be fabricated, together with field effect devices, in VESTIC-based integrated circuits. As a result, the VESTIC technology could become the new original BiCMOS technology. [ABSTRACT FROM AUTHOR]

The performance enhancement of integrated circuits relying on dimension scaling (i.e., following Moore's Law) is more and more challenging owing to the physical limit of Si materials. Monolithic three-dimensional (M3D) integration has been considered as a powerful scheme to further boost up the system performance. Two-dimensional (2D) materials such as MoS2 are potential building blocks for constructing upper-tier transistors owing to their high mobility, atomic thickness, and back-end-of-line (BEOL) compatible processes. The concept to integrate 2D material-based devices with Si field-effect transistor (FET) is technologically important but the compatibility is yet to be experimentally demonstrated. Here, we successfully integrated an n-type monolayer MoS2 FET on a p-type Si fin-shaped FET with 20 nm fin width via an M3D integration technique to form a complementary inverter. The integration was enabled by deliberately adopting industrially matured techniques, such as chemical mechanical planarization and e-beam evaporation, to ensure its compatibility with the existing 3D integrated circuit process and the semiconductor industry in general. The 2D FET is fabricated using low-temperature sequential processes to avoid the degradation of lower-tier Si devices. The MoS2 n-FETs and Si p-FinFETs display symmetrical transfer characteristics and the resulting 3D complementary metal-oxide-semiconductor inverter show a voltage transfer characteristic with a maximum gain of ~38. This work clearly proves the integration compatibility of 2D materials with Si-based devices, encouraging the further development of monolithic 3D integrated circuits. [ABSTRACT FROM AUTHOR]

A series of thieno[3,2- b ]thiophene (TT) flanked para -azaquinodimethane (p -AQM) based quinoidal conjugated polymers PAQM2TT-T , PAQM2TT-BT and PAQM3TT were designed in a strategy to extend the aromatic-quinoidal π-system. The three polymers were synthesized by Stille polycondensation, and their opto-electronic properties and device performance in field-effect transistors have been explored. From absorption spectroscopy, the polymers show low bandgaps (1.54–1.57 eV) and high HOMO energy levels. They exhibit typical p-type behavior according to the results of the characterization of the field-effect transistors with average charge carrier mobilities of 0.08 cm2 V−1 s−1 for PAQM2TT-T , 0.12 cm2 V−1 s−1 for PAQM2TT-BT and 0.05 cm2 V−1 s−1 for PAM3TT. This report presents an alternative π-extended quinoidal-donor strategy to control the molecular design and properties of new p -AQM-based conjugated polymers. • A novel monomer unit containing thienothiophene and p-azaquinodimethane moieties has been designed and synthesized. • Pi-extented aromatic-quinoidal systems have been prepared. • Bottom-gate top-contact field-effect transistors show mobilities up to 0.12 cm2 V−1 s−1. [ABSTRACT FROM AUTHOR]

The van der Waals heterojunction of graphene and MoS 2 has drawn extensive research in recent years, since it combines the advantages of both materials. The thermal transport across the interface is an important issue in practical application, which has been seldom experimentally studied for graphene/MoS 2 heterojunction. Previous work only focused on the phonon coupling without considering the role of interfacial electronics, which caused a deviation between experimental and theoretical results. Herein, we employed photo-thermal Raman technique to characterize the interfacial thermal conductance of graphene/MoS 2 heterojunction and revealed a value of 93.2 ± 10.2 MW/m2K on average. This value is much larger than theoretical predictions. Using source-drain bias (V D) and gate voltage in a field effect transistor device, we achieved effect regulation of interfacial electron transport and corresponding thermal conductance in a range of 55.1 ± 5.8 to 304.2 ± 32.1 MW/m2K. At V D with different signs, we uncovered a possible thermal rectification at the interface. We owed the change of interfacial thermal conductance to electron-assisted phonon-coupling, when electron's transfer between graphene and MoS 2 may results in the phonon density redistribution. [Display omitted] [ABSTRACT FROM AUTHOR]

Specific and label‐free detection of biological interactions is paramount to a plethora of technological applications ranging from home‐care diagnostics to smart agriculture and home security. The biologically‐modified field‐effect transistor (BioFET) is a promising sensing platform due to its inherent signal amplification, low power, and miniaturization. In the following a low‐cost meta‐nano‐channel BioFET (MNC BioFET) is reported that provides means to electrostatically control the size, shape, and location of the conducting channel such as to enhance the coupling between the locally‐occurring electrostatics of the biological interactions and the electrodynamics of the underlying conducting channel. Moreover, it provides means to electrostatically control the Debye screening length at the sensing area to increase the readout signal. The MNC BioFET is fabricated in a large‐scale silicon chip foundry that ensures robustness and stability, optimal noise levels and signal amplification, repeatability, and ultimate miniaturization with the potential for high‐end multiplexing in ultra‐small samples. In the current study, a specific and label‐free sensing of prostate specific antigen with the MNC BioFET is demonstrated, and show the dependency of the sensor signal on the channel configuration. Finally, an order of magnitude enhancement in readout signal is demonstrated by the electrostatic control of the screening length at the sensing area. [ABSTRACT FROM AUTHOR]

Herein, we report a portable point-of-care testing (POCT) device based on an aptamer-engineered extended-gate field-effect transistor (EG-FET) for therapeutic monitoring of the drug methotrexate. This method was shown to be highly sensitive, efficient, and convenient to use, features contributing to its realizing a clinical detection of drugs in blood. [ABSTRACT FROM AUTHOR]

Polaritons in two-dimensional van der Waals (vdW) materials possess extreme light confinement, which have emerged as a potential platform for next-generation biosensing and infrared spectroscopy. Here, we propose an ultra-thin and electric tunable graphene/hexagonal boron nitride/graphene metasurface for detecting molecular fingerprints over a broad spectrum. The vdW metasurface supports hybrid plasmon–phonon polariton resonance with high-quality factor (Q > 120) and electrically controlled broadband spectra tunability from 6.5 to 7 μm. After coating a thin layer of bio-molecular (e.g., CBP) on top of the metasurface, the molecular absorption signatures can be readout at multiple spectral points and, thus, achieve broadband fingerprint retrieval of bio-molecules. Additionally, our electric tunable metasurface works as an integrated graphene-based field-effect transistor device, without the need of multiple resonance generators such as angle-resolved or pixelated dielectric metasurfaces for broadband spectra scanning, thereby paving the way for highly sensitive, miniaturized, and electrically addressed biosensing and infrared spectroscopy. [ABSTRACT FROM AUTHOR]

In the present hyper-scaling era, memory technology is advancing owing to the demand for high-performance computing and storage devices. As a result, continuous work on conventional semiconductor-process-compatible ferroelectric memory devices such as ferroelectric field-effect transistors, ferroelectric random-access memory, and dynamic random-access memory (DRAM) cell capacitors is ongoing. To operate high-performance computing devices, high-density, high-speed, and reliable memory devices such as DRAMs are required. Consequently, considerable attention has been devoted to the enhanced high dielectric constant and reduced equivalent oxide thickness (EOT) of DRAM cell capacitors. The advancement of ferroelectric hafnia has enabled the development of various devices, such as ferroelectric memories, piezoelectric sensors, and energy harvesters. Therefore, in this review, we focus the morphotropic phase boundary (MPB) between ferroelectric orthorhombic and tetragonal phases, where we can achieve a high dielectric constant and thereby reduce the EOT. We also present the role of the MPB in perovskite and fluorite structures as well as the history of the MPB phase. We also address the different approaches for achieving the MPB phase in a hafnia material system. Subsequently, we review the critical issues in DRAM technology using hafnia materials. Finally, we present various applications of the hafnia material system near the MPB, such as memory, sensors, and energy harvesters. [ABSTRACT FROM AUTHOR]

Traditional reconstruction protocols in atom probe tomography frequently feature image distortions for multiphase materials, due to inaccurate geometric assumptions regarding specimen evolution. In this work, the authors’ outline a new reconstruction protocol capable of correcting for many of these distortions. This new method uses predictions from a previously developed physical model for specimen field evaporation. The application of this new model-driven approach to both an experimental semiconductor multilayer system and a fin field-effect transistor device (finFET) is considered. In both systems, a significant reduction in multiphase image distortions when using this new algorithm is clearly demonstrated. By being able to quantitatively compare model predictions with experiment, such a method could also be applied to testing and validating new developments in field evaporation theory. [ABSTRACT FROM AUTHOR]

Flexible artificial synapses, which use flexible electronic devices to simulate biological synapses, are the cornerstone of brain‐like computers and artificial intelligence systems. Devices based on field‐effect transistors (FETs) are suitable for emulating synaptic functions because of their diverse material selection, controllable parameters, and clear working mechanism. In addition, owing to their material fabrication and structural design, FETs can realize the special operation mechanisms of devices for constructing flexible artificial synapses with multiple functions. Herein, the essential principles of carrier transport in flexible artificial synapses based on FETs are focused. First, the selection of materials, carrier transfer mechanisms, and synaptic functions of flexible synaptic devices based on various transistors are summarized in detail. Subsequently, the applications of flexible synaptic devices in conformal artificial tactile and visual systems are introduced. Finally, future challenges and opportunities of flexible synaptic devices toward artificial neuromorphic electronics are discussed. [ABSTRACT FROM AUTHOR]

Ta-based high- κ dielectrics can be synthesized via the oxidation of TaS2 films. In this study, we investigated the wet and dry oxidation of TaS2 films via thermal annealing and plasma irradiation, respectively. The specific vibration observed via Raman spectroscopy, the bonding states observed via x-ray photoelectron spectroscopy, and capacitance measurements confirmed the oxidation of TaS2 films with a dielectric constant of ∼14.9. Moreover, the electrical transport of the TaS2 films along the in-plane direction indicated a change in conductivity before and after the oxidation. The thickness of the oxidized film was estimated. Accordingly, the layer-by-layer oxidation was limited to approximately 50 nm via plasma irradiation, whereas the TaS2 films within 150 nm were fully oxidized via thermal annealing in ambient air. Therefore, a Ta-oxide/TaS2 structure was fabricated as a stack material of insulator and metal when the thickness of the pristine film was greater than 50 nm. In addition, Ta-oxide films were integrated into bottom-gated two-dimensional (2D) field-effect transistors (FETs) using the dry transfer method. 2D FETs with multilayer MoTe2 and MoS2 films as p -type and n -type channels, respectively, were successfully fabricated. In particular, the Ta-oxide film synthesized via dry oxidation was used as a gate dielectric, and the device process could be simplified because the Ta-oxide/TaS2 heterostructure can function as a stack material for gate insulators and gate electrodes. An anti-ambipolar transistor consisting of an MoTe2/MoS2 heterojunction was also fabricated. For the transfer characteristics, a relatively sharp on-state bias range below 10 V and sufficiently high peak-to-valley ratio of 106 at V DS = 3 V were obtained using the high-κ gate dielectric of Ta-oxide despite the presence of the multilayer channels (∼20 nm). [ABSTRACT FROM AUTHOR]

In this work, we investigated how the electrical and photoelectrical properties of InSe based devices depend on the interfaces made with standard materials such as SiO2, BN, and PMMA. The use of a BN layer is found to not only change the carrier type but also weaken the out-of-plane vibration of InSe. Field-effect transistor devices show a p-type behavior for InSe on SiO2, while for InSe on BN, the majority carriers are electrons. Moreover, due to the weakened electron–phonon interaction the electron mobility of InSe on BN is more than two magnitudes greater than its hole mobility on SiO2. A p–n junction diode is also demonstrated with InSe/SiO2 and InSe/BN with a rectification ratio as high as 102 and a photoresponsivity of 52 A/W, which can be enhanced to 103 and 1.6 × 104 A/W with a PMMA coverlayer. Our results may be useful for the design of high-performance van der Waals heterojunction photodetectors. [ABSTRACT FROM AUTHOR]

A tunneling-based ternary CMOS (T-CMOS) offering a low standby current and fast switching speed is developed using a novel device structure for field-effect transistors (FETs). In the new transistor devices, referred to as vertical-channel double-gate (VCDG)-FETs, a vertical current path from drain to source is formed on the drain, and a body placed below the drain is electrically isolated, except for the tunneling junction appearing at the drain and body interface. At the junction, most of the OFF-state current flows, which is independent of the gate voltage. Furthermore, the OFF-state current can be further reduced to the order of 10−17 A by employing a drain with a retrograded doping profile. In this profile, the channel–drain junction tunneling current, which varies with the gate voltage, is substantially suppressed to less than the body–drain junction tunneling current in the OFF state. In addition, an electrostatic channel controlled using double gates facilitates a small subthreshold swing (SSW) of 65 mV/dec. With p- and n-channel VCDG-FETs, a T-CMOS exhibiting three logic states is developed with a standby current on the order of 1 pA and transfer characteristics with a very narrow transition width. [ABSTRACT FROM AUTHOR]

With the growing demands in flexible electronics, the development of plastic and organic materials has gained increased interest. In this focus review, the design concepts and recent advances of organic liquid crystalline materials in optoelectronic devices were introduced. Thermotropic liquid crystalline materials are categorized into three types: calamitic, discotic, and cholesteric types according to the structures of rod‐like, disk‐like, and chiral rod‐like molecules, respectively. Numerous liquid crystalline materials have been successfully incorporated in organic electronic devices. Notably, smectic liquid crystals hold great promise as semiconducting channel, floating gate electret, and charge transporting interlayer in field‐effect transistors, nonvolatile memory, and photovoltaics, respectively. This review sheds light on the great potential and importance of the organic liquid crystalline material for optoelectronic device applications. [ABSTRACT FROM AUTHOR]

To employ graphene's rapid conduction in 2D devices, a heterostructure with a broad bandgap dielectric that is free of traps is required. Within this paradigm, h-BN is a good candidate because of its graphene-like structure and ultrawide bandgap. We show how to make such a heterostructure by irradiating alternating layers of a-C and a-BN film with a nanosecond excimer laser, melting and zone-refining constituent layers in the process. With Raman spectroscopy and ToF-SIMS analyses, we demonstrate this localized zone-refining into phase-pure h-BN and rGO films with distinct Raman vibrational modes and SIMS profile flattening after laser irradiation. Furthermore, in comparing laser-irradiated rGO-Si MS and rGO/h-BN/Si MIS diodes, the MIS diodes exhibit an increased turn-on voltage (4.4 V) and low leakage current. The MIS diode I-V characteristics reveal direct tunneling conduction under low bias and Fowler-Nordheim tunneling in the high-voltage regime, turning the MIS diode ON with improved rectification and current flow. This study sheds light on the nonequilibrium approaches to engineering h-BN and graphene heterostructures for ultrathin field effect transistor device development. [ABSTRACT FROM AUTHOR]

Silicon displacement defects are caused by various effects. For instance, epitaxial crystalline silicon growth and ion implantation often result in defects induced by the fabrication process, whereas displacement damage is induced by terrestrial cosmic radiation. Clustered displacement damage reportedly reduces the on-state current (Ion) in ordinary MOSFETs. In the case of an extremely scaled device such as a nanosheet field-effect transistor (NS-FET), the impact of displacement defect size was analyzed on the basis of the NS dimensions related to the device characteristics. In this study, we investigated the effect of displacement defects on NS-FETs using technology computer-aided design; the simulation model included quantum transport effects. The geometrical conditions, temperatures, trap concentrations, and scattering models were considered as the variables for on-state current reduction. [ABSTRACT FROM AUTHOR]