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4H-SiC/ SiO 2 interface states play a major role in the performance and reliability of modern 4H-SiC metal–oxide–semiconductor field effect transistors (MOSFETs). To gain new insights into these interface states, we developed a cryogenic measurement technique that uses photon-assisted electron depopulation to probe device performance limiting 4H-SiC/ SiO 2 interface states. This technique enables the characterization of shallow as well as deep states at the 4H-SiC/ SiO 2 interface of fully processed devices using a cryogenic probe station. Our method is performed on n-channel 4H-SiC MOSFET test structures with deposited oxide and postoxidation anneal. We identify conditions under which the electrons remain trapped at 4H-SiC/ SiO 2 interface states and trigger the controlled photon-assisted electron depopulation within a range of photon energies. This allows us to prove the presence of near interface traps, which have previously been found in thermally grown 4H-SiC MOS structures. Our results are supported by device simulations. Additionally, we study the impact of irradiation intensity and light exposure time on the photon-induced processes. [ABSTRACT FROM AUTHOR]

We propose a main mechanism of large valley splitting experimentally observed at the interface of buried oxide (BOX)/silicon-on-insulator (SOI) structures. Silicon metal-oxide-semiconductor field effect transistors fabricated on a SIMOX (001) substrate, which is a kind of the SOI substrate, that is annealed at high temperatures for a long time are known to exhibit large valley splitting, but the origin of this splitting has long been unknown. Extended zone effective-mass approximation predicts that strain significantly affects valley splitting. In this study, we analyzed valley splitting based on this theory and found that the shear strain along [110] of approximately 5% near the BOX interface is a promising source for large valley splitting. [ABSTRACT FROM AUTHOR]

With the proportional reduction of metal–oxide–semiconductor field effect transistor (MOSFET) devices, the short channel effect, the parasitic effect, and the field strength effect are significantly enhanced, the proportion of parasitic resistance increases, and the non-intrinsic noise also increases, which seriously affects the working efficiency of the device. However, existing research mainly focuses on the intrinsic noise of MOSFET, and there is little research on the non-intrinsic noise; furthermore, the models describing the relationship between non-intrinsic noise, device structure, and bias have not yet been addressed. Therefore, in this paper, 90, 65, 32, 10, and 5 nm MOSFETs are studied. The rate of the intrinsic ballistic parameter is introduced to set up the source–drain current model and the non-intrinsic noise model. The source–drain current model is consistent with the theoretical model, numerical simulation, and experimental results in the literature. Finally, the relationship between the non-intrinsic noise and the bias and the device parameters are analyzed, and the conclusion is helpful to improve the working efficiency, lifetime, and response speed of nanoscale MOSFET devices. [ABSTRACT FROM AUTHOR]

Reducing the working temperature and increasing sensitivity and selectivity has always been a research hotspot in the field of MOS based gas sensors. In this work, improved triethylamine (TEA) sensing performance and mechanism of SnO2 by doping Pd have been investigated. SnO2 nanoparticles and Pd-SnO2 with different doping amounts of Pd (0%, 0.1%, 0.3%, 0.5%, and 0.7%) were successfully prepared by the hydrothermal method. The size of SnO2 nanoparticles is very uniform (∼15 nm). The SnO2 sensor exhibited the highest sensitivity to ethanol at 290 °C. After Pd doping, Pd/SnO2 sensors not only reduced the optimum working temperature but transformed selectivity from ethanol to TEA. In the Pd-SnO2 system, the 0.5Pd-SnO2 sensor exhibited high sensitivity (61), fast response-recovery properties (16 s/6 s) to 50 ppm TEA, lower detection limits (0.1 ppm), good repeatability, and higher selectivity. Furthermore, based on density functional theory calculations, the improved TEA sensing performance of 0.5Pd-SnO2 sensors can be attributed to the improved surface activity of SnO2 by Pd doping and the catalytic activation of O2 and TEA by Pd. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hierarchical MoS 2 /WS 2 heterostructures in dual carbon layers (HC@MoS 2 /WS 2 @NCs) nanocomposites are constructed as an advanced anode for SIBs. • The internal hard carbon and outer N dopped carbon coating improve the structural stability of MoS 2 /WS 2 during Na+ insertion/extraction process. • The built-in electric field in the MoS 2 /WS 2 heterointerface can further motivate electrons/ions transfer. The escalating global demand for clean energy has spurred substantial interest in sodium-ion batteries (SIBs) as a promising solution for large-scale energy storage systems. However, the insufficient reaction kinetics and considerable volume changes inherent to anode materials present significant hurdles to enhancing the electrochemical performance of SIBs. In this study, hierarchical MoS 2 /WS 2 heterostructures were constructed into dual carbon layers (HC@MoS 2 /WS 2 @NC) and assessed their suitability as anodes for SIBs. The internal hard carbon core (HC) and outer nitrogen-doped carbon shell (NC) effectively anchor MoS 2 /WS 2 , thereby significantly improving its structural stability. Moreover, the conductive carbon components expedite electron transport during charge–discharge processes. Critically, the intelligently engineered interface between MoS 2 and WS 2 modulates the interfacial energy barrier and electric field distribution, promoting faster ion transport rates. Capitalizing on these advantageous features, the HC@MoS 2 /WS 2 @NC nanocomposite exhibits outstanding electrochemical performance when utilized as an anode in SIBs. Specifically, it delivers a high capacity of 415 mAh/g at a current density of 0.2 A/g after 100 cycles. At a larger current density of 2 A/g, it maintains a commendable capacity of 333 mAh/g even after 1000 cycles. Additionally, when integrated into a full battery configuration with a Na 3 V 2 (PO 4) 3 cathode, the Na 3 V 2 (PO 4) 3 //HC@MoS 2 /WS 2 @NC full cell delivers a high capacity of 120 mAh/g after 300 cycles at 1 A/g. This work emphasizes the substantial improvement in battery performance that can be attained through the implementation of dual carbon confinement, offering a constructive approach to guide the design and development of next-generation anode materials for SIBs. [ABSTRACT FROM AUTHOR]

In recent years, silicon‐based room temperature Terahertz (THz) detectors have become the most optimistic research area because of their high speed, low cost, and unimpeded compatibility with mainstream complementary metal‐oxide‐semiconductor (CMOS) device technologies. However, Silicon (Si) suffers from low responsivity and high noise at THz frequencies. In this review, the recent advances in Si‐based THz detectors using silicon‐on‐insulator (SOI) substrates are presented. These offer several advantages over bulk counterparts, such as reduced parasitic capacitance, enhanced electric field confinement, and improved thermal isolation. The different types of THz detectors exploiting SOI substrate, such as conventional metal‐oxide‐semiconductor field effect transistors (MOSFETs), junction‐less MOSFETs, junction‐less nanowires field effect transistors (JLNWFETs), micro‐electromechanical system (MEMS), metal‐semiconductor‐metal (MSM) structures, and single electron transistor (SET), are discussed, and their key performances in terms of responsivity, noise equivalent power (NEP), bandwidth, and dynamic range are compared. The challenges and opportunities for further improvement of SOI THz detectors, such as device scaling, integration, and modulation, are also highlighted. This review may offer compelling evidence supporting the idea that SOI THz detectors have the potential to facilitate high performance, low power consumption, and scalability—qualities essential for advancing next‐level technologies. [ABSTRACT FROM AUTHOR]

Cubic silicon carbide (3C‐SiC) has superior mobility and thermal conduction over that of widely applied hexagonal 4H‐SiC. Moreover, much lower concentration of interfacial traps between insulating oxide gate and 3C‐SiC helps fabricate reliable and long‐life devices like metal‐oxide‐semiconductor field effect transistors. However, the growth of high‐quality and wafer‐scale 3C‐SiC crystals has remained a big challenge up to now despite decades‐long efforts by researchers because of its easy transformation into other polytypes during growth, limiting the development of 3C‐SiC‐based devices. Herein, we report that 3C‐SiC can be made thermodynamically favored from nucleation to growth on a 4H‐SiC substrate by top‐seeded solution growth technique, beyond what is expected by classical nucleation theory. This enables the steady growth of high‐quality and large‐size 3C‐SiC crystals (2–4‐inch in diameter and 4.0–10.0 mm in thickness) sustainable. The as‐grown 3C‐SiC crystals are free of other polytypes and have high‐crystalline quality. Our findings broaden the mechanism of hetero‐seed crystal growth and provide a feasible route to mass production of 3C‐SiC crystals, offering new opportunities to develop power electronic devices potentially with better performances than those based on 4H‐SiC. [ABSTRACT FROM AUTHOR]

Electrospinning has revolutionized the field of semiconductor metal oxide (SMO) gas sensors, which are pivotal for gas detection. SMOs are known for their high sensitivity, rapid responsiveness, and exceptional selectivity towards various types of gases. When synthesized via electrospinning, they gain unmatched advantages. These include high porosity, large specific surface areas, adjustable morphologies and compositions, and diverse structural designs, improving gas-sensing performance. This review explores the application of variously structured and composed SMOs prepared by electrospinning in gas sensors. It highlights strategies to augment gas-sensing performance, such as noble metal modification and doping with transition metals, rare earth elements, and metal cations, all contributing to heightened sensitivity and selectivity. We also look at the fabrication of composite SMOs with polymers or carbon nanofibers, which addresses the challenge of high operating temperatures. Furthermore, this review discusses the advantages of hierarchical and core-shell structures. The use of spinel and perovskite structures is also explored for their unique chemical compositions and crystal structure. These structures are useful for high sensitivity and selectivity towards specific gases. These methodologies emphasize the critical role of innovative material integration and structural design in achieving high-performance gas sensors, pointing toward future research directions in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

Electrically detected magnetic resonance and near-zero field magnetoresistance are techniques that probe defect states at dielectric interfaces critical for metal–oxide–semiconductor (MOS) electronic devices such as the Si/SiO2 MOS field effect transistor (MOSFET). A comprehensive theory, adapted from the trap-assisted recombination theory of Shockley, Read, and Hall, is introduced to include the spin-dependent recombination effects that provide the mechanism for magnetic field sensitivity. [ABSTRACT FROM AUTHOR]

In order to replace the phosphor screen of a proximity-gated x-ray framing camera with a readout circuit using a time-interleaved structure, this paper carries out the design of a high-isolation RF switch. In this paper, a Metal-Oxide-Semiconductor Field Effect Tube (MOSFET) switching circuit is designed to achieve high isolation and low insertion loss at 0.5–3 GHz. This solves the problem that the switching circuit cannot be turned off properly due to the parasitic capacitance of MOSFETs in the process of RF signal transmission, resulting in signal feedthrough. It also ensures that the input signal can be transmitted to the output intact when the switching circuit is turned on. High isolation is achieved by using parallel resonance to increase the voltage division and series resonance to leak the current. The switch achieves 76 dB isolation and 0.07 dB insertion loss at 1 GHz frequency. Isolation is increased by adding parallel branches near the 2 and 3 GHz frequency points, achieving greater than 33 dB isolation from 0.5 to 3 GHz. [ABSTRACT FROM AUTHOR]

This paper presents non-reciprocal information transfer between two mass-spring chains enabled using an electromechanical cell incorporating a metal–oxide–semiconductor field effect transistor (MOSFET). Mechanical information propagating through an input chain is converted into an electrical signal, and vice versa for an output chain, using a permanent magnet and a conducting coil in each chain. The conducting coils are coupled electrically via a MOSFET, leading to giant isolation and unidirectional signal transfer. We present theory, numerical simulations, and an experimental demonstration of the concept. The proposed system can be implemented as a "sonocoupler", an acoustic analog of an optocoupler, which can isolate one mechanical system from another while transmitting information in a unidirectional manner. [ABSTRACT FROM AUTHOR]

Amplifiers of the buildup signal of piezo emitters in the hardware of a hydroacoustic research complex are described. They are designed to amplify short-term signals with amplitude, frequency, and phase modulation at a frequency of 1 MHz. A feature of the linear signal amplifier with amplitude modulation is the use of an amplifier with current feedback, which is characterized by high speed properties. A feature of a switch signal amplifier with a constant amplitude (frequency and phase modulation) is the use of optocouplers in the control pulse shaper circuit of the output MOSFETs (metal–oxide–semiconductor field effect transistor), which ensured the symmetry of the pulses. The high duty cycle of the amplified signals made it possible to avoid the need for special heat sinks and to perform a simple and compact implementation of the circuits. The gain of the linear amplifier was 18 dB, the maximum amplitude of the output signal was 80 V, and the gain of the switch amplifier and switch signal amplitude were 26 dB and 200 V, respectively. Specific circuit solutions are given. [ABSTRACT FROM AUTHOR]

We study how nitridation, applied to SiON gate layers, impacts the reliability of planar metal-oxide-semiconductor field effect transistors (MOSFETs) subjected to negative and positive bias temperature instability (N/PBTI) as well as hard breakdown (HBD) characteristics of these devices. Experimental data demonstrate that p-channel transistors with SiON layers characterized by a higher nitrogen concentration have poorer NBTI reliability compared to their counterparts with a lower nitrogen content, while PBTI in n-channel devices is negligibly weak in all samples independently of the nitrogen concentration. The Weibull distribution of HBD fields extracted from experimental data in devices with a higher N density are shifted towards lower values with respect to that measured in MOSFETs, and SiON films have a lower nitrogen concentration. Based on these findings, we conclude that a higher nitrogen concentration results in the aggravation of BTI robustness and HBD characteristics. [ABSTRACT FROM AUTHOR]

RF-DC rectifier circuit is a key component of microwave wireless energy transmission system (MWPT), and the performance of its core rectifier components (MOS field effect transistors or Schottky diodes) determines the upper limit of the rectifier circuit efficiency. Especially for the large amount of low power density RF energy in the 2.45G band that exists in our environment, the efficiency of existing MWPT systems to collect and utilise it is not ideal, and the overall rectification efficiency is low, limiting its application in weak energy density. In view of this, this paper proposes and designs a new direct bandgap GePb (DR-GePb) quantum well trench N-MOSFET for 2.45G weak energy microwave wireless transmission, aiming to improve rectification efficiency at weak energy densities. The joint simulation of the circuit of Mixmode device further shows that compared with the traditional Si-based MOS transistor, the rectification efficiency of the new device designed in this paper is significantly improved in the weak energy density range, and the rectification efficiency can reach 9.2% and 19.28% at the input power density of − 19.3 dBm and − 7.8 dBm, respectively. The rectification efficiency at input power densities of − 19.3 dBm and − 7.8 dBm is 9.2% and 19.28%, respectively, which is 6.5 times and 2.4 times higher than that of Si-based MOS under the same conditions. The technical solution and related conclusions in this paper can provide useful references for solving the problems related to weak energy density wireless collection. [ABSTRACT FROM AUTHOR]

The performance of the control system relies on the linearity of the sensor, which can be influenced by various factors such as aging and alterations in material properties. However, current sensor linearization techniques, such as utilizing neural networks and piecewise regression models in the digital domain, suffer from issues like errors, excessive power consumption, and slow response times. To address these constraints, this investigation employs a translinear based analog circuit to realize neural networks and piecewise regression models for the purpose of linearizing the selected sensors. A conventional feed-forward back propagation network is constructed and trained using the Levenberg-Marquardt algorithm. The developed linearization algorithm is implemented using a translinear circuit, where the trained weights, biases, and sensor output are fed as input current sources into the current-mode circuit. Further in this work, the piecewise regression model is designed and implemented using a translinear circuit and the breakpoint is determined using 'R' language. The simulation results indicate that the implementation of the current-mode circuit with metal-oxide-semiconductor field-effect transistors (MOSFETs) for the neural network algorithm leads to a substantial reduction in full-scale error as compared to the piecewise current mode model. Additionally, a performance analysis was conducted to compare the utilization of current-mode circuits with digital approaches for the linearization of sensors. The proposed translinear implementation surpasses the other researcher's work by delivering notable results. It showcases a significant improvement in linearity, ranging from 60% to 80%, for the selected sensors. Furthermore, the proposed implementation excels not only in linearity but also in terms of both response speed and power consumption. The improvement in the linearity of the sensor can be enhanced further by replacing the MOSFETs with bipolar transistors or any versatile materials such as gallium arsenide or gallium nitride-based transistors. [ABSTRACT FROM AUTHOR]

There is always a need for low-power, area-efficient VLSI (Very Large-Scale Integration) design and this need is increasing day by day. However, conventional design methods based on Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) devices and Complementary Metal-Oxide-Semiconductor Transistor (CMOS) technology cannot meet the performance requirements. The memristor, as a promising computing and memory integration device, offers a new research idea for conventional logic circuit structure and architecture innovation, given its non-volatility, scalability, low power consumption, fast switching speed, etc. This paper proposes a brief overview of the characteristics and current status of memristor-based logic circuits and analyzes their applications in numerical expression and memory. The benefits and drawbacks of various analog logic circuit structures are summarized and compared. In addition, some solution strategies for these issues are presented. Finally, this paper offers prospects for the applications of memristors in the logic implementation of large-scale memristor arrays, the novel structure of in-memory computing, and neural network computing. [ABSTRACT FROM AUTHOR]

In the present study, we characterize the nature of interface states in silicon carbide (SiC) metal–oxide–semiconductor (MOS) systems by analyzing the electrical characteristics of MOS field effect transistors (MOSFETs) based on the results of numerical calculations. In the calculation, the potential distributions and energy sub-bands were calculated by solving Poisson and Schrödinger equations, respectively. As a result, we demonstrate that the defect-induced localized levels in the bandgap are subjected to quantum confinement at the inversion layer, leading to the increase in their energy levels. The result implies that the conventional interface defects (e.g., near-interface oxide traps), which create defect states at certain energy levels measured from the vacuum level, are unlikely to be the major origin of the interface states in SiC MOS systems. The interface state density is almost uniquely determined by the oxide formation process (as oxidation or interface nitridation) and independent of the acceptor concentration (3 × 1015–1 × 1018 cm−3). It is also suggested that the drain current decrease observed in heavily doped MOSFETs is mainly due to the decrease in the drift mobility rather than that in the free carrier density. [ABSTRACT FROM AUTHOR]

We characterized an intrinsic interface defect, called the "PbC center," formed at 4H-SiC(0001)/SiO2 interfaces by means of electron-spin-resonance (ESR) and electrically detected-magnetic-resonance (EDMR) spectroscopies. The formation of the PbC center was observed with a spin density of 3–4 × 1012 cm−2 after standard thermal oxidation. This center could be effectively removed by the NO post-oxidation-anneal (POA) process or ultra-high-temperature oxidation and could be passivated by H atoms via the H2 POA process. There was a clear correlation between the PbC center and field-effect mobility (μFE) of 4H-SiC(0001) metal–oxide–semiconductor field effect transistors (MOSFETs). The PbC center decreased μFE because this center acts as electron traps, reducing the free-carrier density in the inversion channel of 4H-SiC(0001) MOSFET. We also examined the counter doping effect of NO POA by introducing 15N impurities; however, the counter doping of 15N donors was not detectable by ESR (much lower than 2 × 1011 cm−2). Highly sensitive EDMR measurements revealed that the PbC center has two isotropic hyperfine (HF) interactions at 1.3 and 6.8 mT and suggested that its main 13C HF interaction should be larger than 14 mT. Based on the present experimental data, the origin of the PbC center was ascribed as a carbon-related interface defect that forms a C–H bond after hydrogen passivation. This feature is similar to that of the porous-PbC centers (carbon dangling-bond centers) found in porous-SiC/SiO2 systems. However, their HF signatures indicated that the PbC center at 4H-SiC(0001)/SiO2 interfaces and the porous-PbC centers in porous-SiC should be different centers associated with different wave functions. [ABSTRACT FROM AUTHOR]

Detailed investigations of the pre-oxidation phosphorus implantation process are required to increase the oxidation rate in 4H-SiC metal-oxide-semiconductor (MOS) capacitors. This study focuses on the SiO2/SiC interface characteristics of pre-oxidation using phosphorus implantation methods. The inversion channel mobility of a metal-oxide-semiconductor field effect transistor (MOSFET) was decreased via a high interface state density and the coulomb-scattering mechanisms of the carriers. High-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) were used to evaluate the SiO2/SiC interface's morphology. According to the energy-dispersive X-ray spectrometry (EDS) results, it was found that phosphorus implantation reduced the accumulation of carbon at the SiO2/SiC interface. Moreover, phosphorus distributed on the SiO2/SiC interface exhibited a Gaussian profile, and the nitrogen concentration at the SiO2/SiC interface may be correlated with the content of phosphorus. This research presents a new approach for increasing the oxidation rate of SiC and reducing the interface state density. [ABSTRACT FROM AUTHOR]

The wide bandgap semiconductors SiC and GaN are commercialized for power electronics and for visible to UV light-emitting diodes in the case of the GaN/InGaN/AlGaN materials system. For power electronics applications, SiC MOSFETs (metal–oxide–semiconductor field effect transistors) and rectifiers and GaN/AlGaN HEMTs and vertical rectifiers provide more efficient switching at high-power levels than do Si devices and are now being used in electric vehicles and their charging infrastructure. These devices also have applications in more electric aircraft and space missions where high temperatures and extreme environments are involved. In this review, their inherent radiation hardness, defined as the tolerance to total doses, is compared to Si devices. This is higher for the wide bandgap semiconductors, due in part to their larger threshold energies for creating defects (atomic bond strength) and more importantly due to their high rates of defect recombination. However, it is now increasingly recognized that heavy-ion-induced catastrophic single-event burnout in SiC and GaN power devices commonly occurs at voltages ∼50% of the rated values. The onset of ion-induced leakage occurs above critical power dissipation within the epitaxial regions at high linear energy transfer rates and high applied biases. The amount of power dissipated along the ion track determines the extent of the leakage current degradation. The net result is the carriers produced along the ion track undergo impact ionization and thermal runaway. Light-emitting devices do not suffer from this mechanism since they are forward-biased. Strain has also recently been identified as a parameter that affects radiation susceptibility of the wide bandgap devices. [ABSTRACT FROM AUTHOR]

The single-event effect reliability issue is one of the most critical concerns in the context of space applications for SiC VDMOS. In this paper, the SEE characteristics and mechanisms of the proposed deep trench gate superjunction (DTSJ), conventional trench gate superjunction (CTSJ), conventional trench gate (CT), and conventional planar gate (CT) SiC VDMOS are comprehensively analyzed and simulated. Extensive simulations demonstrate the maximum SET current peaks of DTSJ−, CTSJ−, CT−, and CP SiC VDMOS, which are 188 mA, 218 mA, 242 mA, and 255 mA, with a bias voltage VDS of 300 V and LET = 120 MeV·cm2/mg, respectively. The total charges of DTSJ−, CTSJ−, CT−, and CP SiC VDMOS collected at the drain are 320 pC, 1100 pC, 885 pC, and 567 pC, respectively. A definition and calculation of the charge enhancement factor (CEF) are proposed. The CEF values of DTSJ−, CTSJ−, CT−, and CP SiC VDMOS are 43, 160, 117, and 55, respectively. Compared with CTSJ−, CT−, and CP SiC VDMOS, the total charge and CEF of the DTSJ SiC VDMOS are reduced by 70.9%, 62.4%, 43.6% and 73.1%, 63.2%, and 21.8%, respectively. The maximum SET lattice temperature of the DTSJ SiC VDMOS is less than 2823 K under the wide operating conditions of a drain bias voltage VDS ranging from 100 V to 1100 V and a LET value ranging from 1 MeV·cm2/mg to 120 MeV·cm2/mg, while the maximum SET lattice temperatures of the other three SiC VDMOS significantly exceed 3100 K. The SEGR LET thresholds of DTSJ−, CTSJ−, CT−, and CP SiC VDMOS are approximately 100 MeV·cm2/mg, 15 MeV·cm2/mg, 15 MeV·cm2/mg, and 60 MeV·cm2/mg, respectively, while the value of VDS = 1100 V. [ABSTRACT FROM AUTHOR]

In the history of metal–oxide–semiconductor field effect transistor (MOSFET), the quality of its gate oxide has been a cornerstone of the present semiconductor integrated circuits. The changes of gate dielectrics from conventional SiO2 gate oxide into high-k materials has brought us more challenges in various aspects of transistors, especially the reliability improvement when MOSFET dimension is continually scaled. Depending on the making of high-quality gate dielectrics, it plays a major role for the manufacture of high-end CPU with ultra-low power and low leakage, nowadays. There are two major well-known breakdowns in MOSFET's history. Not until 2015, a world first observation of the breakdown, different from soft and hard breakdown, named dielectric fuse breakdown, dFuse, was discovered, as a result of CMOS technology moving into the high-k metal-gate (HKMG) era. In this paper, we will introduce from the inception of the Ig-RTN (random telegraph noise) measurement on the understanding of breakdown in 2008 and briefly describe the fundamentals of the RTN technique. Later in 2015, a version 2.0 of this Ig-RTN measurement, named Ig-transient, was successfully developed to delineate the breakdown path in HKMG transistors, from which a third breakdown, named dielectric fuse breakdown, was discovered. Its origin and physical mechanism have been discussed. This breakdown relies on the understanding of a leakage path in the gate dielectric of MOSFET, especially the movement of oxygen ions and the oxygen vacancies in the gate dielectric. Sophisticated measurement technique has also been developed to identify the traps generated in the gate dielectrics which laid the foundations on the understanding of trap generation as a function of time. In the end, two major applications in memories are presented, one is in the use of one-time-programming memory and the other on the understanding of the switching phenomena involved in the operation of resistance random-access memory (RRAM). [ABSTRACT FROM AUTHOR]

Formaldehyde (HCHO) is an indoor toxic volatile compound (VOC) gas, which can harm respiratory tract of human beings when a person is exposed to low concentration of HCHO for a long time. In this study, an HCHO sensor with high response and low detection limit based on rGO/WO3 (rGW) nanocomposite was successfully synthesized by hydrothermal method. Experimental results depict that the average response value of rGW is about 2000 towards 500 ppm HCHO at room temperature, the response/recovery time is 2.8 s/1.7 s for HCHO at 500 ppb and the low detection limit is 500 ppb. Moreover, rGW exhibits excellent selectivity and good stability. Compared to WO3, the combination of rGO with WO3 can increase the oxygen vacancy on WO3 surface and afford more active sites for capturing HCHO. Furthermore, the formation of electron depletion layer and potential energy barrier between rGO and WO3 increase intrinsic impedance of rGW nanocomposite to further enhance the property of HCHO sensor based on rGW. This study indicates that the combination of rGO with WO3 can efficiently enhance the property of WO3-based HCHO sensor at room temperature, which is conducive to the application of metal oxide semiconductor in field of gas sensors. [ABSTRACT FROM AUTHOR]

With the rapid miniaturization of integrated chips in recent decades, aggressive geometric scaling of transistor dimensions to nanometric scales has become imperative. Recent works have reported the usefulness of 2D transition metal dichalcogenides (TMDs) like MoS2 in MOSFET fabrication due to their enhanced active surface area, thin body, and non-zero bandgap. However, a systematic study on the effects of geometric scaling down to sub-10-nm nodes on the performance of MoS2 MOSFETs is lacking. Here, the authors present an extensive study on the performance of MoS2 FETs when geometrically scaled down to the sub-10 nm range. Transport properties are modelled using drift-diffusion equations in the classical regime and self-consistent Schrödinger-Poisson solution using NEGF formulation in the quantum regime. By employing the device modeling tool COMSOL for the classical regime, drain current vs. gate voltage (ID vs. VGS) plots were simulated. On the other hand, NEGF formulation for quantum regions is performed using MATLAB, and transfer characteristics are obtained. The effects of scaling device dimensions, such as channel length and contact length, are evaluated based on transfer characteristics by computing performance metrics like drain-induced barrier lowering (DIBL), on-off currents, subthreshold swing, and threshold voltage. [ABSTRACT FROM AUTHOR]

Due to Moore's law, it is that predicted the channel length of a metal-oxide-semiconductor Field Effect Transistor (MOSFET) will tend to shrink from the submicron to the nanoscale size. Thus, precision in the manufacturing process has become crucial. This study describes the virtual fabrication as well as the electrical characteristics of a 14nm NMOS double gate with a bilayer graphene/high-K/metal gate. In this device, Hafnium Dioxide (HfO2) is employed as a high-k material, and Tungsten Silicide (WSix) is used as a metal gate. Several Silvaco TCAD Tools, including ATHENA and ATLAS, were utilized in the fabrication and simulation of the device, respectively. According to the simulation results, the optimal threshold voltage (VTH), drive current (ION), and leakage current (IOFF) and subthreshold slope (SS) values are 0.2059 V, 797.5650 µA/µm. 29.5794 nA/µm, and 89.1712x10-3 V respectively. The findings of this research showed that the efficiency of this 14nm double gate n-type MOSFET device is satisfactory because the threshold voltage and leakage current parameters are in accordance with ITRS 2013, and that it may have been utilized as a utility man in future modelling and optimization efforts. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductor gas sensors are widely used to detect toxic and inflammable gases in industrial production and daily life. The main research hotspot in this field is the synthesis of gas sensing materials. Previous studies have shown that incorporating two or more metal oxides to form a heterojunction interface can exhibit superior gas sensing performance in response and selectivity compared with single phase. This review focuses on mainly the synthesis methods and gas sensing mechanisms of metal oxide heterostructures. A significant number of heterostructures with different morphologies and shapes have been fabricated, which exhibit specific sensing performance toward a specific target gas. Among these synthesis methods, the hydrothermal method is noteworthy due to the fabrication of diverse structures, such as nanorod-like, nanoflower-like, and hollow sphere structures with enhanced sensing properties. In addition, it should be noted that the combination of different synthesis methods is also an efficient way to obtain metal oxide heterostructures with novel morphologies. Despite advanced methods in the metal oxide semiconductors and nanotechnology field, there are still some new issues which deserve further investigation, such as long-term chemical stability of sensing materials, reproducibility of the fabrication process, and selectivity toward homogeneous gases. Moreover, the gas sensing mechanism of metal oxide heterostructures is controversial. It should be clarified so as to further integrate laboratory theory research with practical exploitation. [ABSTRACT FROM AUTHOR]

Migrant organizations (MOs), as associations that are founded, managed, and led by people with migration biographies, have recently emerged as facilitators of social protection interventions. This article is devoted to this barely debated issue of MOs in the field of social protection, by emphasizing their role in facilitating the mobilization and access to cultural capital as an important determinant of protection and wellbeing of people with migration biographies. Specifically, we study how MOs promote the formation and mobilization of skills and resources to be used in different fields, in particular in the education and labor markets. We find that MOs facilitate various occasions for their members to generate migration-specific cultural capital, predominantly in the field of education and language skills. MOs also promote the creation and institutionalization of cultural capital on the labor market. In addition, our results show that people with a migration background appreciate their participation in migrants' organizations, because they allow them to pursue their own projects and find their own way through the different phases of migration and settlement, in often challenging environments. [ABSTRACT FROM AUTHOR]

The radiation effects of metal-oxide-semiconductor (MOS) capacitors based on an Al2O3 gate dielectric were studied using 30 MeV Si heavy ions. To give insights into the types of defects induced by Si ion irradiation in the gate oxide, synergistic experiments involving γ-ray irradiation and Si ion irradiation were carried out. The results revealed that the defects in the as-grown Al2O3 layer were found to be hole trapping centers, whereas Si ion induced new defects were electron trapping centers. The experimental and simulation data of current density-voltage (J-V) curves confirmed that the transmission mechanism of leakage current in the Al2O3 layer was mainly dominated by the Frenkel-Poole mechanism. In detail, the variations of leakage current were mainly due to the attributions of the local built-in electric field-assisted current leakage and the conductive path-assisted current leakage and were found to be dependent on the irradiation condition and Al2O3 thickness. Lastly, the decrease of the gate oxide capacitance of MOS capacitors was attributed to the increase of the series resistance and leakage current in MOS capacitors. [ABSTRACT FROM AUTHOR]

InGaSb-on-insulator (InGaSb-OI) and InAs/InGaAs/InAs-on-insulator (InAs/InGaAs-OI) structures have been realized on Si by a direct wafer bonding (DWB) technology using atomic-layer-deposition Al2O3. While strain introduced in InGaSb channel layers grown on InAs can enhance the hole mobility of the Sb-based channel layers, a difficult issue of fabricating InGaSb-OI wafers is to obtain a smooth InGaSb surface, which is mandatory for wafer bonding. In this study, the surface of a 20-nm-thick In0.185Ga0.815Sb channel grown on an InAs (100) substrate and an InAs (2.5 nm)/In0.185Ga0.815Sb (20 nm)/InAs (2.5 nm) channel with a 20-nm-thick GaSb buffer layer grown on an InAs (100) substrate by metal-organic chemical vapor deposition have a root mean square of the surface roughness as low as 0.16 and 0.22 nm, respectively, over a scan area of 10 × 10 μm2, which are smooth enough to employ the wafer bonding. As a result, the fabrication of the InGaSb-OI wafers by the DWB and the operation of InGaSb-OI p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs) by using the DWB wafers are demonstrated. Also, the performance of InGaSb-OI p-MOSFETs is found to be improved by inserting ultrathin InAs layers between InGaSb and insulating buried oxide layers. An InGaSb-OI and an InAs/InGaAs-OI p-MOSFET under the accumulation-mode operation exhibit a peak mobility of ∼161 and ∼273 cm2/V s, respectively. The channel hole mobility of the InGaSb-OI p-MOSFET is higher than that of the GaSb-on-insulator (GaSb-OI) p-MOSFET and can exceed that of Si p-MOSFETs. [ABSTRACT FROM AUTHOR]

The performance of silicon carbide (SiC)-based metal-oxide-semiconductor field-effect transistors (MOSFETs) is greatly enhanced by a post-oxidation anneal in NO. These anneals greatly improve effective channel mobilities and substantially decrease interface trap densities. In this work, we investigate the effect of NO anneals on the interface density of states through density functional theory (DFT) calculations and electrically detected magnetic resonance (EDMR) measurements. EDMR measurements on 4H-silicon carbide (4H-SiC) MOSFETs indicate that NO annealing substantially reduces the density of near interface SiC silicon vacancy centers: it results in a 30-fold reduction in the EDMR amplitude. The anneal also alters post-NO anneal resonance line shapes significantly. EDMR measurements exclusively sensitive to interface traps with near midgap energy levels have line shapes relatively unaffected by NO anneals, whereas the measurements sensitive to defects with energy levels more broadly distributed in the 4H-SiC bandgap are significantly altered by the anneals. Using DFT, we show that the observed change in EDMR linewidth and the correlation with energy levels can be explained by nitrogen atoms introduced by the NO annealing substituting into nearby carbon sites of silicon vacancy defects. [ABSTRACT FROM AUTHOR]

Vertical metal–oxide–semiconductor field effect transistor (MOSFET) is essential to the future application of ultrawide bandgap β-Ga2O3. In this work, we demonstrated an enhancement-mode β-Ga2O3 U-shaped gate trench vertical metal–oxide–semiconductor field effect transistor (UMOSFET) featuring a current blocking layer (CBL). The CBL was realized by high-temperature annealing under oxygen ambient, which provided electrical isolation between the source and drain electrodes. The CBL thicknesses of different annealing temperatures were derived from C–V measurements and the Fermi level position of the sample surfaces of different annealing temperature was characterized by x-ray photoelectron spectroscopy measurements, indicating good process controllability. Furthermore, photoluminescence spectra were measured to study the effect of oxygen annealing. The fabricated UMOSFET showed normally off with a Vth of 11.5 V, an on-state resistance of 1.48 Ω cm2, a maximum on-state current of 11 A/cm2, an on–off ratio of 6 × 104, and a three-terminal breakdown voltage over 100 V. This work paves a way to form a CBL and broadens the design space for high-power β-Ga2O3 vertical transistors. [ABSTRACT FROM AUTHOR]

In this Letter, lateral slanted-fin-channel β-Ga2O3 metal-oxide-semiconductor field effect transistors (MOSFETs) are demonstrated. A 600-nm thick n-type doped channel layer is adopted to improve output characteristics. The tri-gate structure enhances gate control in the proposed β-Ga2O3 MOSFETs, showing an on/off ratio as high as 109. In particular, the slanted-fin-channel structure, mainly located in the gate region, reduces the peak electric field in the Ga2O3 channel due to the gradual regulation of a threshold voltage. The slanted-fin-channel β-Ga2O3 MOSFETs show a breakdown voltage (Vbr) of 2400 V and a power figure-of-merit of 193 MW/cm2, which are almost 2 and 5.5 times larger, respectively, than those of conventional straight-fin-channel devices. These results imply that the slanted-fin channel structure provides a viable way of fabricating high-performance β-Ga2O3 MOSFET power devices. [ABSTRACT FROM AUTHOR]

A normally off hydrogen-terminated diamond (H-diamond) metal-oxide-semiconductor field effect transistor (MOSFET) is realized by using lanthanum oxide (La2O3) gate dielectric. The threshold voltage is demonstrated to be −0.797 V, indicating that the La2O3-gated H-diamond MOSFET has normally off characteristics. The normally off mode could be greatly ascribed to the low work function of La2O3. Based on the capacitance–voltage (C–V) curves, the dielectric constant of La2O3 is calculated to be as high as 25.6. Moreover, the small hysteresis voltage extracted from the C–V curves exhibits low trapped charge density in the La2O3 layer. The maximum drain–source current, maximum transconductance, subthreshold swing, effective mobility, current on/off ratio, and sheet hole density of La2O3-gated MOSFET with a gate length of 2 μm are calculated to be −13.55 mA/mm, 4.37 mS/mm, 161 mV/dec, 202.2 cm2/V·s, 108, and 6.53 × 1012 cm−2, respectively. This work will significantly promote the development of normally off H-diamond MOSFET devices. [ABSTRACT FROM AUTHOR]

The channel conduction in 4H-SiC metal–oxide–semiconductor field effect transistors (MOSFETs) are highly impacted by charge trapping and scattering at the interface. Even though nitridation reduces the interface trap density, scattering still plays a crucial role in increasing the channel resistance in these transistors. In this work, the dominant scattering mechanisms are distinguished for inversion layer electrons and holes using temperature and body-bias-dependent Hall measurements on nitrided lateral 4H-SiC MOSFETs. The effect of the transverse electric field ( E e f f ) on carrier mobility is analyzed under strong inversion condition where surface roughness scattering becomes prevalent. Power law dependencies of the electron and hole Hall mobility for surface roughness scattering are determined to be E e f f − 1.8 and E e f f − 2.4 , respectively, analogous to those of silicon MOSFETs. Moreover, for n-channel MOSFETs, the effect of phonon scattering is observed at zero body bias, whereas in p-channel MOSFETs, it is observed only under negative body biases. Along with the identification of regimes governed by different scattering mechanisms, these results highlight the importance of the selection of substrate doping and of E e f f in controlling the value of channel mobility in 4H-SiC MOSFETs. [ABSTRACT FROM AUTHOR]

Ion mobility (IM) coupled mass spectrometry (MS) is a versatile tool for analytical separations, characterization, and detection by measuring collision cross-sections and mass-to-charge (m/z) ratios. Traveling wave (TW)-based structures for lossless ion manipulations (TW-SLIM) is an innovative ion drift tube for complex gas phase ion manipulations, which is the key component of traveling wave ion mobility spectrometry (TWIMS). TW-SLIM combines flexible ion path design and traveling wave technology. The traveling wave pulse power supply is used to provide an oscillatory electric fields. Ions in TWIMS are propelled and separated by traveling wave. The operating pressure, TW amplitude and TW frequency of TW pulse have effect on ion motion in TWIMS. In this work, a traveling wave pulse power supply was developed, which mainly consisted of field programmable gate array (FPGA), half-bridge gate driver integrated circuit (IC), metal-oxide-semiconductor field effect transistor (MOSFET), adjustable high voltage module and external trigger signal. The frequency of TW pulse power supply was up to 100 kHz, both rising edge and falling edge were less than 20 ns. The influence of TW amplitude and TW frequency on ions transmission and separation was explored on the home-built instrument platform. The experimental results presented here provide a fundamental understanding of the transmission and separation mechanism in TWIMS. The maximum signal intensity of hexakis (2, 2-difluoroethoxy) phosphazene was at amplitude of 35 V and frequency of 10 kHz. As the traveling wave frequency increased at a fixed traveling wave amplitude, signal intensity of hexakis (2, 2-difluoroethoxy) phosphazene decreased. Ions separations was positively related to frequency when traveling wave amplitude was fixed, while traveling wave amplitude was opposite. The development of traveling wave pulse power supply is valuable for research and development of high resolution TWIMS instrument. [ABSTRACT FROM AUTHOR]

• Some principal theories of surface wettability are summarized. • Two primary strategies for building superhydrophobic surfaces are summarized. • Strategies for achieving reversible wettability transition are highlighted. • Comprehensive review is given on the wettability-related application fields. • Current challenges and future research directions are critically analyzed. Metal oxides (MOs) as a class of indispensable materials in many industrial products have been extensively investigated for a wide range of applications, including energy and environment-related fields. In the applications of MOs, the surface wettability exhibits significant influences on their properties. Hence, the regulation of wettability on MO surfaces with desired surfaces is essential to realize the target properties in various practical applications. In this review, we first present some principal theories of surface wettability and then give a detailed introduction on the synthesis of superhydrophobic and superhydrophilic MO surfaces. Particularly, two primary strategies, including micro-/nano-structures construction and surface modification, for building superhydrophobic MO surfaces are summarized. Next, the smart stimuli-response MO surfaces, which deliver switchable wettability under some external stimulus, and the strategies for achieving reversible wettability transition are highlighted. Subsequently, a comprehensive review is given on the wettability-related application fields of MO surfaces. Finally, the current challenges for surface construction and reversible transitions are critically analyzed, and four future research directions are pointed out in order to offer some constructive clues for the future manipulation and applications of MO surfaces. [ABSTRACT FROM AUTHOR]

This study investigates methods to modulate the effective work function (EWF) and control the multiple threshold voltages (V THs) of metal-oxide-semiconductor (MOS) devices by applying metal electrodes with different work function materials (WFMs), including a single layer of n-type (TaAlC) and p-type (TaAlN) as well as their stacked structures, through atomic layer deposition (ALD). Dual-Work-Function-Metal (DWFM) gate is a crucial aspect of confirming the feasibility of metal gate stacks in MOS devices for a complementary metal-oxide-semiconductor (CMOS) integration scheme. The gate stack structure of p-Si/IL (Inter layer)/HfO 2 /DWFM (p/n-type compatible metal stack)/W exhibits good adhesion and even chemical composition distribution, as evidenced by transmission electron microscope (TEM) and energy dispersive spectrometer (EDS) analysis. By fabricating MOS capacitors using this WFM structure and extracting EWF from the measured capacitance-voltage (C–V) characteristics, EWF values of 4.62 eV and 4.99 eV were identified both before and after annealing using forming gas, indicating pWFM-like properties. These properties are attributed to the strengthened Al–O bonds and reduced C O peaks seen in x-ray photoelectron spectroscopy (XPS) analysis. The use of different Ta precursor from Tris(diethylamido)(tert-butylimido)tantalum(V) (TBTDET) as well as TaCl 5 resulted in the increase of the EWF following the unique p -WFM like feature. As candidates for WFM electrode in metal-oxide-semiconductor field effect transistor (MOSFET) with the DWFMs (n/p stacks) were evaluated, resulting in a V TH of 0.84 V that places in the middle of the V TH shift range from 0.6 V (nWFM) to 1.16 V (pWFM), approximately. The DWFMs allow for modulation of the EWF, which in turn reduces ambiguity in addressing replacement metal gate (RMG) challenges and opens up new avenues for achieving multi-V TH solutions in CMOS integration schemes. [Display omitted] [ABSTRACT FROM AUTHOR]

Owing to the wide application of Mo in a range of fields, the performance requirements for molybdenum products and molybdenum alloys have increased in recent years. In this study, a novel process is developed for the production of the main component of molybdenum powder, namely MoO 2. Subsequently, the thermal stability of the component is measured, and the reduction mechanism is determined to evaluate its effects on the particle size and morphology. Evidently, the H 2 MoO 5 raw material is completely stripped of O 2 2− following a two-step heat-absorption reaction at 247 °C to produce MoO 3 grains with a needle-like structure. These needle-like grains exhibit a lower reduction temperature than commercial MoO 3 , enabling part of the reduction reaction to occur at 440 °C. Additionally, the reaction rate is higher, and the reaction time at the same temperature is approximately half that of the commercial MoO 3. The reaction mechanism associated with the needle-like MoO 3 is mainly governed by chemical vapor transport (CVT), which leads to greater morphological changes, and can effectively regulate the nucleation and growth of MoO 2. A more dispersed ultrafine/nano-MoO 2 powder with an average particle size of 200–700 nm could be successfully prepared at low temperatures by adjusting the reduction temperature of MoO 3 , and to reduce the reduction temperature. It was found that the MoO 2 grains began to grow continuously along the one-dimensional direction under the combined effects of the CVT and gas–liquid–solid growth mechanisms, forming MoO 2 grains with a unique stripe-like morphology. These results are expected to contribute to the production of high-quality molybdenum powder to satisfy the requirements of various research and application fields. • The hydrogen reduction reactions of H 2 MoO 5 and MoO 3 were investigated. • H 2 MoO 5 generated MoO 3 via a two-step endothermic reaction prior to reduction. • Using H 2 MoO 5 , the reaction temperature was lower and the reaction rate was faster. • Ultrafine and uniformly dispersed MoO 2 (200–700 nm) prepared at low temperatures. • Polyhedral MoO 2 with a different morphology to the feedstock was also prepared. [ABSTRACT FROM AUTHOR]

Quality control and assurance of mammography X-ray generators include the use of solid-state detectors and/or ionization chambers calibrated in standard reference radiation fields. The IEC 61267:2005 standard defines reference mammography radiation fields for Mo/Mo anode/filtration, while various anode/filtration combinations are encountered in clinical mammography X-ray units. Not all Secondary Standard Dosimetry Laboratories have an X-ray generator with Mo/Mo radiation setup. Thus, traceability can be established only for the available anode/filter combinations, commonly limited to W/Al. In this study, W/Al radiation fields were established under laboratory conditions by performing half-value layer measurements. Then, four solid-state detectors were characterized. X-ray multimeter performance was evaluated in terms of energy response in the W/Al radiation fields. In the laboratory conditions, the energy response of the dosimeters had a large deviation from unity for dosimeters without appropriate anode/filter combination selected in the software settings, even though most of the dosimeters had a uniform relative response. The discrepancy in the response was further investigated by examining its variation induced by available detector software settings, and it was determined that the dosimeter response can vary up to 20 %. In a clinical setup, the half-value layer was determined, and detector performance was examined. Dosimeters were tested in clinical fields with Mo/Mo, Mo/Rh, W/Rh, W/Ag anode/filter combinations in the X-ray tube voltage range from 25 kV to 35 kV. For most clinical radiation fields, multi-element detectors had energy response deviation within ±5 %. The single-element detector had one software setting available and exhibited strong energy dependence. Extensive testing of detector response, such as presented in this paper. allows for correction factor interpolation based on the half-value layer. • IEC standard defines mammography reference radiation fields only for Mo/Mo. • Clinical mammography spectra differ due to various anode/filtration materials used. • Non-standard W/Al qualities for laboratory calibration purposes were developed. • Software induced changes in X-ray multimeter response for W/Al fields were examined. • Performance of X-ray multimeters in clinical mammography beams was evaluated. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS 2) is a nonlinear optical material with graphene-like structure. In order to further improve the nonlinear optical performance of MoS 2 and expand the application fields of MoS 2 , we report a simple in-situ self-growth method to functionalize MoS 2 nanosheets with metal-organic framework (MOF) for the first time to pursuit excellent reverse saturable absorption performance and optical limiting performance. Firstly, defective MoS 2 nanosheets was obtained by chemical etching with H 2 O 2 and cysteamine was inserted into the sulfur vacancies under ultrasound to obtain MoS 2 –NH 2. Then 5,10,15,20-Tetra (4-carbomethoxyphenyl) porphyrin (TCPP) as MOF active growth sites were grafted on MoS 2 –NH 2 by amido linkage to obtain MoS 2 -TCPP in mild conditions. Finally, flower-like porphyrin-based CuMOF was grown on MoS 2 -TCPP by solvothermal method to obtain MoS 2 -CuMOF with stable structure. The third order nonlinear optical performance of MoS 2 -CuMOF were studied by Z-scan technique. It was found that the third order nonlinear absorption coefficient of MoS 2 -CuMOF was significantly improved compared with MoS 2. Under the same energy of laser irradiation, the third order nonlinear absorption coefficient of MoS 2 -CuMOF nanocomposite in solution was 6 × 10−10 m/W about 2.3 times of the pristine MoS 2 (2.6 × 10−10 m/W). After blending the above materials with polymethyl methacrylate (PMMA) to prepare a solid device, the third order nonlinear absorption coefficient of MoS 2 -CuMOF/PMMA was 18 × 10−10 m/W about 3.6 times of the MoS 2 /PMMA (5 × 10−10 m/W). And MoS 2 -CuMOF/PMMA had better optical limiting ability than MoS 2 /PMMA. The significant improvement in the performance of the composites can be attributed to the energy transfer between MoS 2 and CuMOF, and porphyrin aggregation was inhibited by PMMA after the preparation of devices. Energy transfer can be proved by fluorescence spectroscopy. This work not only provided an example for the covalent functionalization of MoS 2 , but also offered a new method for designing materials with excellent nonlinear optical performance. [Display omitted] • MOF was grown on MoS 2 by a simple in-situ self-growth method to prepare MoS 2 -CuMOF. • MoS 2 -CuMOF had larger third-order nonlinear absorption coefficient. • MoS 2 -CuMOF had excellent properties through energy transfer between components. • MoS 2 -CuMOF can be prepared into PMMA-based optical limiter. [ABSTRACT FROM AUTHOR]

Vertical-type two-dimensional hole gas (2DHG) diamond metal-oxide-semiconductor field effect transistors (MOSFETs), featuring vertical geometry and typically p-channel, are poised for application in future logic technology, high-voltage and high-power miniaturization complementary circuits. P-channel achieving high breakdown voltage and low on-resistance can be realized through the use of p− drift layer, while a trench structure is shown to be beneficial for increasing the drain current density of vertical-type devices. However, the cumulative impact of these key parameters on the performance of vertical-type diamond MOSFETs remains unclear. In this paper, we explore the physical mechanism that how the key parameters design affects on off-state, breakdown and output characteristics has been simulated using Silvaco TCAD tools. We propose a vertical-type trench-gate 2DHG diamond MOSFET that is favorable for general integration applications and exhibits equivalent performance to the double-gate vertical structure without relying on a high concentration of nitrogen doped layer. This demonstrates that our work offers a universal approach for optimizing the comprehensive device performance in vertical-type structures, accounting for the effects of multiple parameters across all wide bandgap material-based FETs. [Display omitted] • Vertical-type diamond MOSFET with double-gate and trench-gate models were simulated. • Key parameters (i.e. N-doped layer, drift layer, trench width, depth) were simulated. • N-implanted layer acts as leakage current blocking layer, ensuring reliable turn-off. • The drift layer contributes to a more uniform distribution of the electric field. • Trench-gate devices exhibited high performance with low nitrogen doping concentration. [ABSTRACT FROM AUTHOR]

The accumulation capacitance oscillations behavior in the n-InAs metal-oxide-semiconductor structures with different densities of the built-in charge (Dbc) and the interface traps (Dit) at temperature 4.2 K in the magnetic field (B) 2–10 T, directed perpendicular to the semiconductor-dielectric interface, is studied. A decrease in the oscillation frequency and an increase in the capacitance oscillation amplitude are observed with the increase in B. At the same time, for a certain surface accumulation band bending, the influence of the Rashba effect, which is expressed in the oscillations decay and breakdown, is traced. The experimental capacitance-voltage curves are in a good agreement with the numeric simulation results of the self-consistent solution of Schrödinger and Poisson equations in the magnetic field, taking into account the quantization, nonparabolicity of dispersion law, and Fermi-Dirac electron statistics, with the allowance for the Rashba effect. The Landau quantum level broadening in a two-dimensional electron gas (Lorentzian-shaped density of states), due to the electron scattering mechanism, linearly depends on the magnetic field. The correlation between the interface electronic properties and the characteristic scattering times was established. [ABSTRACT FROM AUTHOR]

A Through Silicon Via (TSV) is a key component for 3D integrated circuit stacking technology, and the diameter of a TSV keeps scaling down to reduce the footprint in silicon. The TSV aspect ratio, defined as the TSV depth/diameter, tends to increase consequently. Starting from the aspect ratio of 10, to improve the TSV sidewall coverage and reduce the process thermal budget, the TSV dielectric liner deposition process has evolved from sub-atmospheric chemical vapour deposition to plasma-enhanced atomic layer deposition (PE-ALD). However, with this change, a strong negative shift in the flatband voltage is observed in the capacitance-voltage characteristic of the vertical metal-oxide-semiconductor (MOS) parasitic capacitor formed between the TSV copper metal and the p-Si substrate. And, no shift is present in planar MOS capacitors manufactured with the same PE-ALD oxide. By comparing the integration process of these two MOS capacitor structures, and by using Elastic Recoil Detection to study the elemental composition of our films, it is found that the origin of the negative flatband voltage shift is the positive charge trapping at the Si/SiO2 interface, due to the positive PE-ALD reactants confined to the narrow cavity of high aspect ratio TSVs. This interface charge trapping effect can be effectively mitigated by high temperature annealing. However, this is limited in the real process due to the high thermal budget. Further investigation on liner oxide process optimization is needed. [ABSTRACT FROM AUTHOR]

For the improvement of the traditional evaluation effect of the automobile sound quality, an evaluation model of automobile sound quality is constructed based on BP neural network. The first is to introduce the basic principle of the BP neural network in detail. The second is to use the MGC parameters to establish the vehicle interior sound conversion model. The converted sound characteristic parameters are taken into the WORLD model to synthesize the new sound signals. Furthermore, the wavelet decomposition method is used to remove noise from the synthesized sound signals. Finally, a sound evaluation model based on BP neural network is established. The sound quality of automobiles can be better evaluated by carrying out the ABX test and MOS test in the field of sound conversion. For the newly synthesized sound signal and the target sound signal, it can be seen that the newly synthesized sound signal is more inclined to the target sound signal, and the sound quality is better. In addition, the sound quality is tested through loudness, roughness, sharpness, and level A in the field of sound quality evaluation. The final results show that the quality of newly synthesized sound is better, and the average errors of sound signals meet the sound standard. Therefore, the constructed sound conversion model and the sound evaluation model are feasible and effective. [ABSTRACT FROM AUTHOR]

Herein, the effect of Yb, Al, Cu and Au metal substrates on the electrical performance of germanium oxide-based devices is reported. Back-to-back Schottky-type metal-insulator-metal (MIM) electronic devices with the structure (Yb, Al, Cu, Au)/GeO2/C are prepared by vacuum evaporation under a vacuum pressure of 10−5 mbar. Capacitance-voltage characteristic curve analysis on these devices have shown that, while the forward-biased Al/GeO2/C displays NMOS (enhanced N-channel metal oxide semiconductor) characteristics, Cu/GeO2/C and Au/GeO2/C show inverted NMOS and PMOS fields effect transistor (FET) characteristics under forward and reverse biasing conditions, respectively. A large scale (8–737 nm) of depletion width and built-in potentials engineering is possible via metallic substrate selection. In addition, current-voltage characteristic curve analysis have shown that the dominant transport mechanism is by electric field-assisted tunneling through narrow barriers. The only device that showed current rectification was the Yb/GeO2/C device. The absence of the recertification property from the (Al, Cu, Au)/GeO2/C devices is assigned to the large surface roughness of the metal substrates. Analysis of the capacitance, conductance, impedance and reflection coefficient spectra in the frequency domain of 0.01–1.80 GHz have shown that the proposed device structures can exhibit features of negative capacitance effect devices and tunable microwave/radio wave cavities. The observed notch frequency values of the (Yb, Al, Cu, Au)/GeO2/C devices make them suitable for use as bandpass/reject filters suitable for 4G technology. [ABSTRACT FROM AUTHOR]

Herein, Tungsten trioxide-gallium sulfide heterojunctions which are prepared by the thermal evaporation technique under a vacuum pressure of 10-5 mbar are employed as active media to fabricate a multifunctional device. The WO3/Ga2S3 (WG) heterojunctions which are deposited onto Yb substrates and top contacted with Au pads of areas of 1.5x10-2 cm² displayed electronic hybrid device structure composed of two Schottky arms connected to a pn junction. The constructed Yb/WG/Au devices showed tunneling diode characteristics with current conduction dominated by thermionic emission and quantum mechanical tunneling. In additions, the capacitance-voltage characteristic curves indicated the formation of PMOS and NMOS under reverse and forwards biasing conditions demonstrating a metal oxide semiconductor fields effect (MOSFET) transistor characteristics. Moreover, the impedance spectroscopy tests on the devices have shown that the device can perform as tunable microwave resonator suitable for 5G technologies. The resonator showed frequency based capacitance tunability and displayed microwave band pass/reject filter characteristics. The microwave cutoff frequency of the Yb/WG/Au band filters reaches 9.65 GHz with voltage standing wave ratios of 1.06 and return loss factor of ~29 dB. [ABSTRACT FROM AUTHOR]

[Display omitted] Piezocatalysis, driven by mechanical energy and piezoelectric effect, is of great potential in addressing the environmental issues. In this work, a piezoelectric catalyst was fabricated by growing few-layer MoS 2 nanosheets onto CuS, for the piezocatalytic degradation of Rhodamine B (RhB), methylene blue (MB) and hexavalent chromium (Cr (VI)). The excellent removal efficiency of Cr (VI) and RhB can be reached 100% within 180 s, through the piezocatalysis of CuS/MoS 2 -0.6 driven by mechanical stirring in the dark. Impressively, the piezoelectric current of CuS/MoS 2 -0.6 is 48 and 35.7 times higher than that of pure CuS and MoS 2 , respectively. The significantly enhanced piezocatalytic performance can be ascribed to the formation of CuS/MoS 2 heterojunction and the piezoelectric field generated by MoS 2 nanosheets, which promotes the efficient separation of electrons and holes. This study provides insights into strategies to improve catalytic performance through utilizing mechanical energy and opens a new horizon for environmental remediation. [ABSTRACT FROM AUTHOR]

We investigated the nucleation sites of expanded single Shockley-type stacking faults (1SSFs) in a silicon carbide (SiC) metal–oxide–semiconductor field effect transistor (MOSFET) and demonstrated epitaxial layers designed for bipolar-degradation-free SiC MOSFETs. Since the sufficient hole density just below the basal plane dislocation (BPD)-threading edge dislocation (TED) conversion points induces 1SSF expansion, we derived the dependence of the nucleation depth on the applied current condition from the BPD-TED conversion points of 1SSFs. We first simulated and determined the three-step current conditions applied to a body diode in a SiC MOSFET so that a sufficient amount of holes would be supplied to the drift layer, to the buffer layer, and inside the substrate in the SiC MOSFET. An in operando x-ray topography analysis was conducted with the determined conditions for dynamically visualizing 1SSF expansion motions, and 1SSFs expanded at different forward current densities were successfully extracted. The depths of the BPD-TED conversion points of the extracted 1SSFs were analyzed, and it was experimentally clarified that these depths, i.e., the nucleation sites of expanded 1SSFs, became deeper with forward current densities. The bipolar degradation characteristics of SiC MOSFETs were evaluated as a function of the forward current density, and the validity of the simulation model was verified by experimental results. We also confirmed that bipolar degradation can be suppressed to some extent by using a substrate with a low BPD density, and SiC MOSFETs with a high-nitrogen-concentration epitaxial layer showed high reliability under bipolar operation. Depending on the application of SiC MOSFETs, the epitaxial layers should be designed to prevent the hole density inside the substrate from exceeding the threshold for 1SSF expansion. [ABSTRACT FROM AUTHOR]