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Nickel/photoredox catalysis has emerged as a powerful platform for exploring nontraditional and challenging cross-couplings. Herein, a metallaphotoredox catalytic protocol has been developed on the basis of a tertiary amine-ligated boryl radical-induced halogen atom transfer process under blue-light irradiation. A wide variety of aryl and heteroaryl bromides featuring different functional groups and pharmaceutical moieties were facilely coupled to rapidly install C(sp3)-enriched aromatic scaffolds. The compatibility of Lewis base-ligated borane with nickel catalysis was well exemplified to extend the chemical space for Ni-catalyzed cross-electrophile coupling.

In this work, an in situ C-doped GaN layer inserted into the n-GaN region of ultraviolet light-emitting diodes (UV LEDs) is proposed and investigated to mitigate the severe current crowding effect of GaN-based UV LEDs. Since carbon is a common impurity for GaN grown by metal-organic chemical vapor deposition (MOCVD), it plays the role of deep acceptor in GaN. Taking advantage of the feasibility of C-doped GaN in the MOCVD growth process, the effect of in situ C-doped GaN insertion layer grown under various temperatures on UV LED performance is investigated and the optimized temperature is obtained. The experimental results show that the in situ C-doped GaN insertion layer is able to enhance the light output of UV LEDs, and the uniform light-emission distribution proves that the alleviated current crowding is achieved. For UV LEDs with the in situ GaN insertion layer grown at 800° C, the wall-plug efficiency (WPE) shows an increase of 10.9% compared with the conventional GaN-based UV LEDs at 20 mA. The numerical simulation results also show the more uniform and higher hole concentrations in the quantum well (QW), which is attributed to the conductivity modulation of the n-type region induced by the C-doped GaN insertion layer.

In this work, the electrical performance degradation and circuit burnout in gallium nitride (GaN)-based microwave monolithic integrated circuit (MMIC) power amplifiers (PAs) under on-state with high drain bias have been studied in-depth. It is found that when the drain bias increases from 30 to 90 V, the saturation drain current decreases by 16%, and the output power drops significantly by 4.5 dB. With the aid of photon emission measurements (PEMs) and scanning electron microscopy (SEM), it is found that catastrophic burnout occurs in the power-stage GaN HEMTs and the MIM capacitors, respectively. For the GaN HEMT, electrons in the channel can gain enough energy with the transverse high electric field to become hot electrons. One part of hot electrons can surmount the AlGaN/GaN interface barrier and then induce leakage paths in the AlGaN layer, resulting in a significant leakage current. The other part of hot electrons will collide with the lattice near the drain edge (DE) and induce significant electron trapping, which will result in a significant longitudinal local electric field. When a critical electric field is achieved, catastrophic burnout occurs. The results obtained from the TCAD simulation verified it. For the MIM capacitor, the failure is attributed to the dielectric breakdown at the edge of the capacitor, which also plays an important role in the circuit deterioration.

The influence of proton radiation on the electrical performance of the gallium oxide (Ga2O3) Schottky barrier diode (SBD) was investigated from the perspective of defect in this work. The electrical performance is significantly degraded with the increase of proton irradiation fluence. After the irradiation fluence of $2\times 10^{{13}}$ p/cm2, it was found that the ON-state current density ( ${J}_{\text {on}}$ ) was reduced by 57%, the OFF-state current density ( ${J}_{\text {off}}$ ) was reduced by more than one order of magnitude, and the breakdown voltage ( ${V}_{\text {br}}$ ) increased by nearly 350 V. Based on the frequency-dependent conductance technique, the Ni/Ga2O3 interface changed slightly after proton irradiation. In addition, the deep-level transient spectroscopy (DLTS) measurements show that the concentration of the deep-level defect ( ${E}_{c}$ -0.75 eV) within the Ga2O3 drift layer has a clear response to radiation, and was significantly increased from $4.1\times 10^{{13}}$ cm-3 to $5.4\times 10^{{14}}$ cm-3 after the irradiation with a fluence of $2\times 10^{{13}}$ cm-2. Moreover, the carrier concentration extracted by capacitance-voltage (C–V) shows that the carrier removal rate caused by this defect is 550 cm-1. Considering the change of electrical performance, it indicates that the ${E}_{c}$ -0.75 eV defect within the Ga2O3 drift layer rather than the interface state determines the degradation of devices.

In this work, we report on achieving enhanced performance NiOx/beta gallium oxide ( $\beta $ -Ga2O3) heterojunction p-n diodes (HJDs) through synergistic interface engineering (SIE), which can greatly improve the electrical characteristics and interface characteristics of HJDs. It is shown that the NiOx surface undergoes morphological improvement and hole concentration enhancement after the UV/ozone treatment (UVO). Owing to the improved interfacial properties of Ni/NiOx, the forward conduction current of NiOx/ $\beta $ -Ga2O3 HJD has significantly increased. Furthermore, the HJD performance can be improved by SIE with UVO and postannealing, especially for the reverse breakdown characteristics. Finally, a high-performance HJD without any terminal structure is obtained, which exhibits a low specific on-resistance of 2.47 m $\Omega \cdot $ cm2 and a high breakdown voltage of 1355 V, yielding a high Baliga’s figure of merit (BFOM) of 0.743 GW/cm2, which is a 219.17% enhancement in performance compared to untreated device. This work offers a practical and effective strategy for developing advanced Ga2O3 devices with exceptional performance metrics, paving the way for future technological breakthroughs.

In this article, the offline fault estimation via a sampled-output-data-driven adaptive observer is investigated for a class of Takagi–Sugeno fuzzy descriptor nonlinear systems. The additive actuator faults and disturbances are involved. At the signal receiving end, the discrete sampled output signals from systems are obtained through wireless transmission. To achieve the offline fault estimation for the fuzzy descriptor system, the cubic spline interpolation fitting approach is first applied to fit the receiving sampled output data into a dynamic fitting function. Then, the dynamic fitting function is further applied to construct and drive an adaptive observer related to the system in consideration. Compared with the existing observers, the designed discrete sampled-output-data-driven adaptive observer does not require interface docking with the original system equipment. The fault on the system can be estimated offline with a certain degree of accuracy via the provided observer. Stability conditions for the estimation error dynamics are given, which can be converted into linear matrix inequalities. Finally, two numerical models are used to validate the effectiveness of the proposed offline fault estimation method.

Degradation of SiC power mosfets under repetitive short-circuit (SC) stress is significant to the reliability of the power systems. A deep level transient spectrum method together with split C-V method to split the trap characteristics of the SiC mosfets is proposed. The degradation details of different locations in SiC planar gate (PG) and trench gate (TG) mosfets are comprehensively studied in this article. Thus, a criterion is provided to guide the SC degradation from the aspect of traps. The main degradation of the channel region is the increase of border traps for PG mosfet and newly generated interface traps for TG mosfet. The interface traps domain the degradation in the JFET region for both devices. The degradations of gate oxide for both devices affect the channel and JFET regions especially in the first set of SC cycles. The degradation of body diode is mainly influenced by hole traps in PG mosfet, but by electron traps first then hole traps newly generated in TG mosfet. Finally, the degradation locations of PG and TG mosfets are effectively characterized. It is the first time to use the trap measurement method to separate the different degradation in every part of the devices in detail. The method proposed in this article can better reflect the failure mechanisms related to dynamics and evaluate the operation of devices effectively, which provides very useful guidance for the reliability design and utilization of SiC mosfets.

In this work, the source of the radio frequency loss in GaN-on-Si materials is investigated in detail. Through measuring S parameters and capacitor voltage characters of samples with different reactive ion etching depths, it is revealed that the radio frequency loss derives from the p-type parasitic channel at the Si interface induced by the diffusion aluminum atom. Based on this viewpoint, the donor phosphorus compensation method was proposed to compensate the p-type parasitic channel of the diffusion Al atom. The approximately linear distribution state of the in situ aluminum diffusion and the normal distribution state ex situ phosphorus ion implantation is revealed according to secondary ion mass spectroscopy and transport of ions in matter (TRIM) simulation methods. Moreover, the variable power phosphorus ion implantation is employed to finely compensate the parasitic channel. As a result, an ultralow coplanar waveguide RF loss of 0.4 dB/mm at 40 GHz is obtained with 600 nm metal thickness. The results in this work have an instructive significance for the application of GaN-on-Si in the future.

Wide-band-gap (WBG) perovskite solar cells have gained significant attention in silicon/perovskite tandem solar cells due to their suitable band gap and high open circuit voltage (Voc). However, the phase separation and film defects of WBG perovskite films have severely hindered the larger Vocand high efficiency. Herein, we demonstrate a simple passivation approach with potassium thiocyanate and methylammonium chloride dual-passivation, which could effectively increase the film grain size and suppress ion migration and phase separation. Consequently, the wide-band-gap perovskite (1.69 eV) solar cells with dual-passivation exhibit a relatively high power conversion efficiency (PCE) of 20.35% with a larger Vocof 1.20 V. Meanwhile, a perovskite mini-module with an area of 12 cm2obtains an impressive PCE of 17.4%. The optimized state-of-the-art cells with dual-passivation exhibit a favorable storage and phase stability.

ABSTRACTBackground and ContextComputational thinking (CT) has been increasingly added to K-12 curricula, prompting teachers to grade more and more CT artifacts. This has led to a rise in automated CT assessment tools.ObjectiveThis study examines the scope and characteristics of publications that use machine learning (ML) approaches to assess students’ CT competencies from four perspectives: the educational context in which the assessments were implemented, the data used to train and validate ML algorithms, the specific ML algorithms used, and the aspects of CT assessed.MethodThe PRISMA approach and Arksey and O’Malley’s methodological framework for scoping reviews were adopted to search and screen studies.FindingsML algorithms have been increasingly used to assess CT competencies. However, this study identified several research gaps in the literature: existing studies were mostly conducted in the context of programming or other learning activities related to computing science; datasets used by the ML algorithms were generally small; the most frequently used algorithms were regression techniques, naive Bayes, neural networks, clustering, and natural language processing, whereas no studies used reinforcement learning; and CT competencies were not comprehensively assessed.ImplicationsThe applications of ML in CT assessments have the potential to enable personalized learning, improve assessment validity, reduce the workload of graders, and gain insights from large datasets by uncovering complex and subtle patterns.

Detecting cyanobacteria in environments is an important concern due to their crucial roles in ecosystems, and they can form blooms with the potential to harm humans and nonhuman entities. However, the most widely used methods for high-throughput detection of environmental cyanobacteria, such as 16S rRNA sequencing, typically provide above-species-level resolution, thereby disregarding intraspecific variation. To address this, we developed a novel DNA microarray tool, termed the CyanoStrainChip, that enables strain-level comprehensive profiling of environmental cyanobacteria. The CyanoStrainChip was designed to target 1277 strains; nearly all major groups of cyanobacteria are included by implementing 43,666 genome-wide, strain-specific probes. It demonstrated strong specificity by in vitromock community experiments. The high correlation (Pearson’s R> 0.97) between probe fluorescence intensities and the corresponding DNA amounts (ranging from 1–100 ng) indicated excellent quantitative capability. Consistent cyanobacterial profiles of field samples were observed by both the CyanoStrainChip and next-generation sequencing methods. Furthermore, CyanoStrainChip analysis of surface water samples in Lake Chaohu uncovered a high intraspecific variation of abundance change within the genus Microcystisbetween different severity levels of cyanobacterial blooms, highlighting two toxic Microcystisstrains that are of critical concern for Lake Chaohu harmful blooms suppression. Overall, these results suggest a potential for CyanoStrainChip as a valuable tool for cyanobacterial ecological research and harmful bloom monitoring to supplement existing techniques.

A metal-free photosensitized 1,2-imino-sulfamoylation of olefins by employing a tailor-made sulfamoyl carbamate as the difunctionalization reagent has been established. This protocol exhibits versatility across a broad substrate scope, including aryl and aliphatic alkenes, leading to the synthesis of diverse β-imino sulfonamides in moderate to good yields. This method is characterized by its metal-free reaction system, mild reaction conditions, excellent regioselectivity, and high atom economy, serving as a promising platform for the preparation of β-amino sulfonamide-containing molecules, particularly in the context of drug discovery.

Foot activity can reflect numerous physiological abnormalities in the human body, making gait a valuable metric in health monitoring. Research on flexible sensors for gait monitoring has focused on high sensitivity, wide working range, fast response, and low detection limit, but challenges remain in areas such as elasticity, antibacterial activity, user-friendliness, and long-term stability. In this study, we have developed a novel capacitive pressure sensor that offers an ultralow detection limit of 1 Pa, wide detection ranges from 1 Pa to 2 MPa, a high sensitivity of 0.091 kPa–1, a fast response time of 71 ms, and exceptional stability over 6000 cycles. This sensor not only has the ability of accurately discriminating mechanical stimuli but also meets the requirements of elasticity, antibacterial activity, wearable comfort, and long-term stability for gait monitoring. The fabrication method of a dual dielectric layer and integrated composite electrode is simple, cost-effective, stable, and amenable to mass production. Thereinto, the introduction of a dual dielectric layer, based on an optimized electrospinning network and micropillar array, has significantly improved the sensitivity, detection range, elasticity, and antibacterial performance of the sensor. The integrated flexible electrodes are made by template method using composite materials of carbon nanotubes (CNTs), two-dimensional titanium carbide Ti3C2Tx(MXene), and polydimethylsiloxane (PDMS), offering synergistic advantages in terms of conductivity, stability, sensitivity, and practicality. Additionally, we designed a smart insole that integrates the as-prepared sensors with a miniature instrument as a wearable platform for gait monitoring and disease warning. The developed sensor and wearable platform offer a cutting-edge solution for monitoring human activity and detecting diseases in a noninvasive manner, paving the way for future wearable devices and personalized healthcare technologies.

Photonic reservoir computing (RC) is a simple and efficient neuromorphic computing framework for human cortical circuits, which is featured with fast training speed and low training cost. Photonic time delay RC, as a simple hardware implementation method of RC, has attracted widespread attention. In this paper, we present and experimentally demonstrate a time delay RC system based on a Fabry Perot (FP) laser for multiple tasks processing. Here, the various tasks are attempted to perform in parallel in the multiple longitudinal modes of the FP laser. It is found that the time delay RC system based on the FP laser can successfully handle different tasks across multiple longitudinal modes simultaneously. The experimental results demonstrate the potential of the time delay RC system based on the FP laser to achieve multiple tasks processing, providing various possibilities for improving the information processing ability of neural morphology RC systems, and promoting the development of RC systems.

Mesoporous GaN-based multiple quantum wells (MP MQWs) with MP GaN-distributed Bragg reflectors (MP GaN DBRs) are obtained viaelectrochemical etching in a HNO3solution. Wafer-scale MP MQWs with MP GaN DBRs have a smooth surface, low root-mean-square roughness (RRMS), and high reflectivity. Then, the p-GaN layer is grown on the MP MQWs with the MP GaN DBR substrate. Compared with as-grown light-emitting devices (AG LEDs), MP LEDs with MP GaN DBRs possess an increased and blue-shifted luminescence emission. The luminescence enhancement results from the reduced density of dislocations of MP MQWs and the highly reflective effect of MP GaN DBRs. Also, the blue shift is due to reduced stress in the MQW layer.

In this study, we demonstrate a robust nonvolatile memristor based on polyethylenimine (PEI) with thermally stable resistive switching behaviors by doping silver ions. This polymeric memristor exhibits remarkable performances with excellent endurance, large ON/OFF ratio, long retention time, and low working voltage. More importantly, the device depicts superior high-temperature environmental stability even when exposed to temperatures up to 100 °C. Moreover, the mechanical properties and typical biosynapse functions of the W/Ag/PEI-AgNO3/Pt/Ti devices on flexible substrate are successfully realized. These results reveal that the W/Ag/PEI-AgNO3/Pt/Ti memristor is promising for wearable and neuromorphic electronics.

The Toom-Cook multiplier (TCM) is the most suitable method for multiplying large integers with key widths typically employed in ECC or RSA due to its computational efficiency. In this brief, we improve the accuracy of hardware TCM algorithm, and propose a TCM-based Barrett modular multiplication algorithm. We provide detailed mathematical proofs for the determination of parameters, error ranges, and input-output bounds, which serve to validate the robustness and reliability of our proposed algorithm. Further, the hardware architecture and the ASIC implementation results under 40nm, 65nm, 90nm process are presented. Compared with existing works, the proposed modular multiplier exhibits superior performance in terms of Area-Time-Product.

Triboelectric nanogenerators (TENGs) have attracted a great deal of attention since they can convert ubiquitous mechanical energy into electrical energy and serve as a continuous power source for self-powered sensors. Optimization of the dielectric material composition is an effective way to improve the triboelectric output performance of TENGs. Herein, the hybrid organic–inorganic lead-iodide perovskite Cs0.05FA0.95–xMAxPbI3was prepared by blade coating and used as a positive friction layer material. Moreover, PVDF-graphene (PG) nanofibers were prepared as negative friction layer materials by electrostatic spinning. The output performance of the TENG was enhanced by varying the MA content of the pervoskite films and the graphene content of the PG nanofibers. The champion output TENG based on Cs0.05FA0.9MA0.05PbI3/PG-0.15 achieved an open-circuit voltage of 245 V, a short-circuit current of 24 μA, and a charge transfer of 80.2 nC. Meanwhile, a maximum power density of 11.23 W m–2was obtained at 100 MΩ. Moreover, the device exhibits excellent energy-harvesting properties, including excellent stability and durability, rapidly charges capacitors, and lights commercial LEDs and digital tubes.

HfO2–ZrO2ferroelectric films have recently gained considerable attention from integrated circuit researchers due to their excellent ferroelectric properties over a wide doping range and low deposition temperature. In this work, different HfO2–ZrO2superlattice (SL) FE films with varying periodicity of HfO2(5 cycles)–ZrO2(5 cycles) (SL5), HfO2(10 cycles)–ZrO2(10 cycles) (SL10), and HfO2(15 cycles)–ZrO2(15 cycles) (SL15) were studied systematically. The HfZrOx(HZO) alloy was used as a comparison device. The SL5film demonstrated improved ferroelectric properties compared to the HZO film, with the 2 times remnant polarization (2Pr) values increasing from 41.4 to 48.6 μC/cm2at an applied voltage of 3 V/10 kHz. Furthermore, the first-order reversal curve diagrams of different SL and HZO capacitors at different states (initial, wake-up, fatigue, and recovery) were measured. The SL capacitors were found to effectively suppress the diffusion of defects during P–Vcycling, resulting in improved fatigue stability characteristics and fatigue recovery capability compared to the HZO capacitor. Moreover, an improved switching speed of the SL films compared to the HZO capacitor was concluded based on the inhomogeneous field mechanism (IFM) model. These results indicate that the SL structure has a high potential in future high-speed ferroelectric memory applications with excellent stability and recovery capability.

Rapid and incredibly sensitive analyte detection is crucial in a variety of settings, including medical diagnostics. However, conventional surface plasmon resonance (SPR) sensors cannot effectively solve the issue of low sensitivity when assaying trace analytes. In this work, the rare Earth oxide Lu2O3 is first introduced to modify fiber optic SPR sensor. By utilizing the inherent advantages of Lu2O3, including high dielectric constant, high breakdown field strength, and high photoelectric conversion efficiency, the electric field around the sensor is effectively increased and high sensitivity detection is achieved. Experimental results show sensitivity of the sensor modified with Lu2O3 nanomaterial reaches 12133.78 nm/RIU in the interval of 1.3614–1.3756. The hexagonal boron nitride (h-BN) is subsequently introduced to further enhance electric field using the charge transfer mechanism. The sensitivity reaches 15065.92 nm/RIU, 3.96 times better than conventional U-shaped fiber SPR sensors. The sensor is compact designed with high sensitivity. There is significant potential for improving the sensitivity aspect of analyte detection.

In this work, GaN HEMTs on 6-inch sapphire substrates are successfully demonstrated for potential 1700 V power applications. The 1.5 $\mu \text{m}$ GaN buffer features a well-controlled crystal quality and uniformity. Benefiting from the insulating sapphire substrate, the buffer vertical leakage channel is cut off, and the lateral parasitic channel at the epitaxy/substrate interface is also significantly suppressed. The fabricated d-mode HEMTs with ${L}_{\text {GD}}$ of 30 $\mu \text{m}$ highlight a high blocking voltage over 3000 V and a low ON-resistance of $17~\Omega \cdot $ mm. The thin-buffer GaN-on-sapphire technology can significantly reduce the epitaxy and processing difficulties, reduce cost, and enable GaN as a strong competitor for 1700 V and even higher-level power applications.

The ≥ 650 V power electronics market penetration by GaN HEMTs on Si has been impeded by the GaN buffer. Recently, GaN-on-sapphire, a promising solution, attracts great attentions. In this work, p-GaN gate HEMTs are successfully manufactured on 6-inch sapphire by CMOS-compatible process in our pilot line. Device process modules of p-GaN selective etching, low-temperature Ohmic contact, and Al2O3/SiO2 passivation have all be realized. The fabricated $16~\mu $ m– ${L}_{\text {GD}}$ devices with a simplified epitaxy and device structure, feature a low ${R}_{\text {ON}}$ of $14.8~\Omega \cdot $ mm, a high ${V}_{\text {TH}}$ of 2 V, and a high OFF-state breakdown voltage (BV) over 1360 V. Further, the nonuniformity of the ${R}_{\text {ON}}$ and ${V}_{\text {TH}}$ across the 6-inch whole wafer is well controlled. Devices also passed the preliminary reliability assessment of high temperature gate bias (HTGB) stress and high temperature reverse bias (HTRB) stress. The high-reliability, high-uniformity, and low-cost p-GaN gate HEMTs on 6-inch sapphire will probably be a strong driven force for the power electronics market in the near future.

We experimentally reported the photoelectric in-memory logic and computing capabilities of HfO2-based ferroelectric optoelectronic memcapacitors (FOMs). By optimizing the annealing process at 600 °C, we achieve a robust noise margin and a substantial photoelectric memory window exceeding 9 fF/ $\mu $ m2, accompanied by an exceptionally low static energy cost below an attojoule per operation. Subsequently, our FOMs gained the capability for reconfigurable photoelectric in-memory Boolean logics of “NAND/NOT” and neuromorphic computing-based hand-written digit image recognition with an accuracy of 92%. These results signify a significant advancement towards energy-efficient sensing-memory-computing electronics, promising next-generation applications in pattern recognition, machine vision, and beyond.

In this letter, CsPbBr3 wafers are obtained through the pressure-induced aggregation of CsPbBr3 powder and further modified through a high-temperature atomized water (HTAW) treatment strategy for the first time. Such a strategy helps to the reconstruction of CsPbBr3 grains in the HTAW environment and thus the densification of the wafer surface. The as-fabricated wafers were used to develop X-ray detectors that exhibited a dark resistivity of $2.43 \times 10^{{9}}~\Omega $ , sensitivity of $143845.34~\mu $ C Gy $_{\text {air}}^{-{1}}$ cm $^{-{2}}$ at 20 V bias, and detection limit of 121.21 nGy s $^{-{1}}$ , which are greatly improved than those of the pristine CsPbBr3 wafers and among the highest performance of reported CsPbBr3perovskite X-ray detectors. Our work provides a reliable strategy for optimizing finished perovskite wafers and enhancing the performance of X-ray detectors.

Reliability of 100-V p-GaN gate power high-electron-mobility transistors (HEMTs) under repetitive short-circuit (SC) stress is investigated in this work, which is a vital topic nowadays because GaN devices are quickly penetrating the medium- and low-voltage power electronics market. In this work, two devices with different processing and structure are compared. Under the stress condition of ${V} _{\text {DD}}$ = 60 V, ${V} _{\text {GS}}$ = 5.8 V, and pulsewidth of $10 \mu \text{s}$ , both the devices show a certain level of degradation with positive ${V} _{\text {TH}}$ shift and current collapse, but no catastrophic failure even after 1000-cycle stress. Guidelines for understanding the failure mechanism and improving the SC capability are achieved as: 1) the floating field plate is effective to smoothen the peak electric field; 2) the extended p-GaN ledge may weaken the electric field crowding effect, reduce the hot carrier injection, and push the trapping area away from the gate area; and 3) higher gate leakage current is beneficial to suppress the positive ${V} _{\text {TH}}$ shift during the SC stress by discharging the negative charges. These guidelines are of paramount significance to promote the SC withstand capability for the p-GaN gate power HEMTs in the future.

Hydrogenated silicon-doped (Si-doped) diamond was prepared by magnetron sputtering silicon on IIa CVD diamond surface and following Si etch/diffuse process at 1000 °C in a hydrogen atmosphere in MPCVD. The silicon doping concentration was higher than $1\times 10^{{18}}$ cm−3 among the depth of 25 nm. The hydrogenated Si-doped diamond surface demonstrated the simultaneous presence of C–H and C–Si bonds in the X-ray photoelectron spectroscopy (XPS) results, and a square resistance of 5500 $\Omega $ /sq with the hole concentration of $1.4\times 10^{{13}}$ cm−2 by contact Hall test. MOSFET fabricated on the hydrogenated Si-doped diamond using traditional hydrogenated diamond device process showed decent device performance. The gold/hydrogenated Si-doped diamond electrodes showed ohmic contact resistivity of $1.02\times 10^{-{5}}\,\,\Omega \cdot $ cm−2 and a contact resistance of 2.4 $\Omega \cdot $ mm. Besides, the 1.5- $\mu \text{m}$ MOSFET device with a threshold voltage of 1.4 V delivered the maximum drain current, ON-resistance, maximum transconductance, and ON/ OFF ratio of −270.5 mA/mm, 39.6 $\Omega \cdot $ mm, 42.4 mS/mm and 8 orders of magnitude. The gate breakdown field and the OFF-state source-drain breakdown field reached 8.4 and 2.17 MV/cm, respectively. The hydrogenated Si-doped diamond provided a promising route for the preparation of high-performance diamond FET devices.

Radiation detectors are important device-level characterization tools of the carrier dynamics of diamond as an ultrawide-bandgap semiconductor. Herein, a high-quality single-crystal diamond was grown on a high-temperature and high-pressure diamond substrate through microwave plasma chemical vapor deposition. We achieved the enhancement of microwave power density by compressing a plasma ball and optimizing the carbon-hydrogen ratio (C/H) within the plasma and thus considerably diminished the impurity and dislocation densities of the diamond epilayer. The full width at half maximum of the X-ray (004) reflection rocking curve was 15 arcsec, and no impurity emission bands were detectable in the photoluminescence spectrum at room temperature (25°C). The radiation detector made from this 200-µm-thick diamond epifilm demonstrated an α-particle response with a charge collection efficiency of 97.03% and energy resolutions of 2.1% for electrons and 97.86% and 1.5% for holes. Furthermore, the product of mobility and lifetime of electrons and holes reached 8 × 10−5and 4.1 × 10−4cm2V−1, respectively. The epitaxial method reduces costs while fulfilling the stringent requirements of radiation detection for commercial applications.

This letter reports on a high-linearity and low-leakage current AlN/GaN/InGaN coupling-channel HEMT (CC-HEMT) utilizing the $\text{N}_{{2}}\text{O}$ oxidation treatment process. Attributed to the channel coupling effect and the gate oxidation process, there is a significant improvement in both the leakage current and linearity figure of merit. The fabricated HEMT exhibited a low off-state leakage of 1.6 nA/mm, which achieves a high on/off current ratio of 109 for AlN-based transistors. The extrinsic ${f}_{\text {T}}$ and ${f}_{\text {max}}$ of the proposed CC-HEMT are 53 and 118 GHz, respectively. The two-tone power level linearity of the proposed CC-HEMT was characterized. The Ka-band output third-order intermodulation point (OIP3) and linearity figure of merit (LFoM) of OIP3/ ${P}_{\text {DC}}$ are 36.4 dBm and 12.9 dB, respectively. These results highlight the application prospects of the AlN/GaN/InGaN CC-HEMT system for high-linearity and low-power consumption power amplifiers.

For 4H-SiC mosfets, the parasitic PiN body diode causes problems such as significant forward voltage drop of body diode and poor reverse recovery characteristics during high-temperature operation. A reasonable solution is a mosfet with an integrated Schottky barrier diode to deactivate the PiN body diode. Since SiC mosfets can operate at extremely high temperatures, the characterization of electrical parameters at high temperatures and changing with the temperature are very important for high power applications and system reliability. However, there is a lack of comparison and analysis of the two devices on electrical properties at ultrahigh temperatures. In this article, a 1.2 kV conventional mosfet and a mosfet integrated with a junction barrier Schottky diode (JBSFET) were fabricated with a consistent process flow. In the temperature range from 300 to 575 K, analytical models of the temperature-dependent electrical parameters of these two devices were established and compared, which were successfully verified by the measurements. These models can provide guidance for ultrahigh temperature applications of JBSFETs. Temperature-related expressions can also be used for junction temperature monitoring of temperature-sensitive electrical parameters. Experimental results show that JBSFET has better third quadrant conduction characteristics and higher temperature stability below 450 K, but loses obvious performance advantages at 575 K. So, the recommended operating temperature range of JBSFET is from 300 to 450 K. Finally, the continuous operation performance of the body diodes in buck converters is analyzed. The higher efficiency of buck converter based on JBSFET's body diode indicates its great application potential in compact converters, especially in the recommended temperature range.

The electronic structure and magnetic properties of single layer Ga2O3in the presence of Ga and O vacancies are studied by first principles method based on density functional theory. The results show that the introduction of Ga vacancy (VGa) leads to a non-zero magnetic moment in single-layer two-dimensional (2D) Ga2O3while VOdoes not. We find that Ga vacancies in two different symmetric positions can lead to spin polarized ground states. Notably, when the VGaratio is greater than 1/16 (indicating one Ga vacancy per 16 Ga atoms), single-layer 2D Ga2O3exhibits semi-metallic properties and its spin polarization reaches 100% at the Fermi level. Calculations of these two Ga vacancy systems also indicate a potential long-range ferromagnetic order at a high Curie temperature (355.8 K). Finally, a single layer 2D Ga2O3with high GaI vacancy (VGaI) ratio can be used as the ferromagnetic layer to obtain the magnetic tunnel junction (MTJ) with high spin filtering effect at the Fermi level. Ga vacant Ga2O3/MgO/Ga vacant Ga2O3MTJ exhibits excellent spin-filtering effect (with 100% spin polarization) and a giant tunneling magneto resistance (TMR) ratio (up to 1.12 × 103%). The results of this paper show that the MTJ based on two-dimensional Ga2O3with room temperature ferromagnetism exhibits reliable performance, showing the possibility of potential applications in spintronics.

Urapidil is an important drug for the treatment of essential hypertension and intravenously in hypertensive emergencies. Herein, an improved route to Urapidil was introduced. The new designed synthetic route starts with the addition reaction of 1-(2-methoxyphenyl)piperazine and oxetane catalyzed by Yb(OTf)3in acetonitrile to form the key intermediate 3-(4-(2-methoxyphenyl)piperazin-1-yl)propan-1-ol. Additionally, 3-(4-(2-methoxyphenyl)piperazin-1-yl)propan-1-ol was purified by recrystallization from the optimized solvents, which was beneficial to large scale production. Intermediate 3-(4-(2-methoxyphenyl)piperazin-1-yl)propyl-4-methylbenzenesulfonate was cast directly for the subsequent reaction without further purification. The overall yield of this route is about 45%. The structure of the final product was well confirmed by 1H-NMR, 13C-NMR and HRMS.

We report on achieving high conductivity hydrogenated boron (B) and silicon (Si) co-doped diamond with a room-temperature Hall result of a square resistance of 2724 ohm/sq, a sheet hole density of ${3}.{3}\times {10} ^{{13}}$ cm−2, and a hole mobility of 68.9 cm2/Vs. The co-doping of B and Si is realized in such a way. First, etch solid BN disk by hydrogen plasma in microwave plasma chemical vapor deposition (MPCVD) system to form B source, and sputter Si film on the diamond surface, and then etch the Si film on diamond sample by hydrogen plasma at 1000 °C in the same MPCVD chamber, and B/Si diffuse to dope diamond. The secondary ion mass spectroscopy of the sample shows that at a depth of $0.3~\mu \text{m}$ , the B and Si doping concentration is higher than ${1}.{0}\times {10} ^{{17}}$ cm−3, and the highest B and Si doping concentration at the surface is ${3}.{7}\times {10} ^{{20}}$ cm−3 and $^{} {1}.{1}\times {10} ^{{20}}$ cm−3, respectively. By using Au to form the ohmic contact electrode, the sample achieves the low ohmic contact resistance of $0.46~\Omega \cdot $ mm and the contact resistivity of ${1}.{6}\times {10} ^{-{5}}\,\,\Omega \cdot $ cm2. The B and Si co-doped diamond provides a new idea for the ohmic contact process optimization of diamond FET devices.

The single event burn-out (SEB) performances of p-GaN gate high electron mobility transistors (HEMTs) were investigated in this article, considering different buffer electron mobilities and incident depths. The output, transfer, and breakdown curves of p-GaN gate HEMTs are not affected by the buffer electron mobility. However, a decrease in buffer electron mobility from 1350 to 265 cm2/(V $\cdot $ s) leads to an increase in SEB voltage from 340 to 460 V. After heavy ion impact, a significant number of electron-hole pairs are generated within the device. Gate breakdown occurs when the electric field at the gate exceeds the critical breakdown strength. Subsequently, an increase in device current is observed, leading to local temperature in HEMT up to 2000 K. The localized high temperature induces the occurrence of SEB. Heavy ion strikes into the buffer layer significantly deteriorate the SEB characteristics. As the incident depth of heavy ion increases, the transient current and device temperature increase correspondingly. Simulation results indicate that the buffer layer has a great effect on SEB characteristics of p-GaN gate HEMTs.

In this work, an energy band-modulated self-aligned p-AlGaN/u-GaN MESFET with a tungsten (W) gate is demonstrated. A high ${I}_{\text {ON}}$ / ${I}_{\text {OFF}}$ of $2\times 10^{{7}}$ , a low subthreshold swing (SS) of 90 mV/dec, and an enhancement-mode threshold voltage ( ${V}_{\text {TH}}$ ) of −0.3 V are obtained. Benefiting from the TMAH-treated etching surface and the post gate annealing-treated Schottky interface, an extremely low trap state density of 2.8– $4.8\times 10^{{11}}$ cm $^{-{2}}\cdot $ eV $^{-{1}}$ was confirmed by the conductance method. The dual-sweep transfer I–V curves show negligible hysteresis and coincide well even after a harsh long-term off-state stress. In addition, the breakdown voltage of the fabricated E-mode p-AlGaN/u-GaN composite-channel MESFET with a gate-to-drain length ( ${L}_{\text {GD}}$ ) of $4~\mu $ m reaches −365 V. The breakdown field reaches approximately 0.9 MV/cm, and the differential on-resistance is 2.8 k $\Omega \cdot $ mm.

The two crucial factors of large scale and high voltage can hardly be balanced for the traditional GaN HEMTs on Si substrates. Recently, one promising solution, GaN-on-sapphire, has attracted great attention. However, the commercialized GaN-on-sapphire wafers ever reported are usually 6 in. It is urgent to develop 8-in GaN-on-sapphire to reduce the cost and meet the market demands. In this work, to the best of our knowledge, an 8-in GaN-on-sapphire wafer is demonstrated for the first time. The sheet resistance ${R}_{\Box }$ exhibits a wafer-level nonuniformity of 4% and an average value of $310 \, \boldsymbol {\Omega } /\Box $ , and the warpage is kept to $30 \, \mu $ m, by dedicatedly tuning the 1.98- $\mu $ m buffer stack. The fabricated 200-V HEMTs exhibit a low ${R}_{\text {ON}}$ of $6.5 \, \boldsymbol {\Omega } \cdot \text {mm}$ , a ${V}_{\text {TH}}$ of -4.2 V, and an off-state breakdown voltage above 500 V without any field plate. The electrical mapping visualizes ${R}_{\text {ON}}$ and ${V}_{\text {TH}}$ distributed in concentric circles across the wafer. Generally, this work demonstrates the feasibility of realizing 8-in GaN-on-sapphire for power electronics applications in the future.