This Special Topic of the Journal of Semiconductors(JoS)features expanded versions of key articles presented at the 2023 IEEE International Conference on Integrated Circuits Technologies and Applications(ICTA),which w...This Special Topic of the Journal of Semiconductors(JoS)features expanded versions of key articles presented at the 2023 IEEE International Conference on Integrated Circuits Technologies and Applications(ICTA),which was held in Hefei,Anhui,China,from October 27 to 29,2023.IEEE ICTA is an IEEE flagship conference in the field of integrated circuits(IC)in China,which provides a communication platform for sharing the state-of-the-art techniques from experts in the field of ICs.Among the 93 papers presented at ICTA 2023,the Technical Program Committee and the Award Committee have selected 4 high-quality articles to recommend to the Special Topic of JoS,covering a wide range of technical fields,including one paper on RF ICs,two papers on Analog ICs and one paper on Wireline ICs.展开更多
Topological magnetotransport in non-collinear antiferromagnets has attracted extensive attention due to the exotic phenomena such as large anomalous Hall effect(AHE),magnetic spin Hall effect,and chiral anomaly.The ma...Topological magnetotransport in non-collinear antiferromagnets has attracted extensive attention due to the exotic phenomena such as large anomalous Hall effect(AHE),magnetic spin Hall effect,and chiral anomaly.The materials exhibiting topological antiferromagnetic physics are typically limited in special Mn_3X family such as Mn_3Sn and Mn_3Ge.Exploring the topological magnetotransport in common antiferromagnetic materials widely used in spintronics will not only enrich the platforms for investigating the non-collinear antiferromagnetic physics,but also have great importance for driving the nontrivial topological properties towards practical applications.Here,we report remarkable AHE,anisotropic and negative parallel magnetoresistance in the magnetron-sputtered Ir_(20)Mn_(80)antiferromagnet,which is one of the most widely used antiferromagnetic materials in industrial spintronics.The ab initio calculations suggest that the Ir_4Mn_(16)(IrMn_4)or Mn_3Ir nanocrystals hold nontrivial electronic band structures,which may contribute to the observed intriguing magnetotransport properties in the Ir_(20)Mn_(80).Further,we demonstrate the spin–orbit torque switching of the antiferromagnetic Ir_(20)Mn_(80)by the spin Hall current of Pt.The presented results highlight a great potential of the magnetron-sputtered Ir_(20)Mn_(80)film for exploring the topological antiferromagnet-based physics and spintronics applications.展开更多
An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a source-FP.The equivalent circui...An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a source-FP.The equivalent circuit of the overall model is composed of parasitic elements,intrinsic transistors,gate-FP,and source-FP networks.The equivalent circuit of the gate-FP is identical to that of the intrinsic transistor.In order to simplify the complexity of the model,a series combination of a resistor and a capacitor is employed to represent the source-FP.The analytical extraction procedure of the model parameters is presented based on the proposed equivalent circuit.The verification is carried out on a 4×250μm GaN HEMT device with a gate-FP and a source-FP in a 0.45μm technology.Compared with the classic model,the proposed novel small-signal model shows closer agreement with measured S-parameters in the range of 1.0 to 18.0 GHz.展开更多
A comprehensive investigation was conducted to explore the degradation mechanism of leakage current in SiC junction barrier Schottky(JBS)diodes under heavy ion irradiation.We propose and verify that the generation of ...A comprehensive investigation was conducted to explore the degradation mechanism of leakage current in SiC junction barrier Schottky(JBS)diodes under heavy ion irradiation.We propose and verify that the generation of stacking faults(SFs)induced by the recombination of massive electron-hole pairs during irradiation is the cause of reverse leakage current degradation based on experiments results.The irradiation experiment was carried out based on Ta ions with high linear energy transfer(LET)of 90.5 MeV/(mg/cm^(2)).It is observed that the leakage current of the diode undergoes the permanent increase during irradiation when biased at 20%of the rated reverse voltage.Micro-PL spectroscopy and PL micro-imaging were utilized to detect the presence of SFs in the irradiated SiC JBS diodes.We combined the degraded performance of irradiated samples with SFs introduced by heavy ion irradiation.Finally,three-dimensional(3D)TCAD simulation was employed to evaluate the excessive electron-hole pairs(EHPs)concentration excited by heavy ion irradiation.It was observed that the excessive hole concentration under irradiation exceeded significantly the threshold hole concentration necessary for the expansion of SFs in the substrate.The proposed mechanism suggests that the process and material characteristics of the silicon carbide should be considered in order to reinforcing against the single event effect of SiC power devices.展开更多
The shuttle effect of lithium polysulfides(LiPSs)and uncontrollable lithium dendrite growth seriously hinder the practical application of lithium-sulfur(Li-S)batteries.To simultaneously address such issues,monodispers...The shuttle effect of lithium polysulfides(LiPSs)and uncontrollable lithium dendrite growth seriously hinder the practical application of lithium-sulfur(Li-S)batteries.To simultaneously address such issues,monodispersed Nb N quantum dots anchored on nitrogen-doped hollow carbon nanorods(NbN@NHCR)are elaborately developed as efficient Li PSs immobilizer and Li stabilizer for high-performance Li-S full batteries.Density functional theory(DFT)calculations and experimental characterizations demonstrate that the sulfiphilic and lithiophilic NbN@NHCR hybrid can not only efficiently immobilize the soluble Li PSs and facilitate diffusion-conversion kinetics for alleviating the shuttling effect,but also homogenize the distribution of Li+ions and regulate uniform Li deposition for suppressing Li-dendrite growth.As a result,the assembled Li-S full batteries(NbN@NHCR-S||Nb N@NHCR-Li)deliver excellent long-term cycling stability with a low decay rate of 0.031%per cycle over 1000 cycles at high rate of 2 C.Even at a high S loading of 5.8 mg cm^(-2)and a low electrolyte/sulfur ratio of 5.2μL mg^(-1),a large areal capacity of 6.2 mA h cm^(-2)can be achieved in Li-S pouch cell at 0.1 C.This study provides a new perspective via designing a dual-functional sulfiphilic and lithiophilic hybrid to address serious issues of the shuttle effect of S cathode and dendrite growth of Li anode.展开更多
Dzyaloshinskii–Moriya interaction(DMI) is under extensive investigation considering its crucial status in chiral magnetic orders, such as Néel-type domain wall(DW) and skyrmions. It has been reported that the in...Dzyaloshinskii–Moriya interaction(DMI) is under extensive investigation considering its crucial status in chiral magnetic orders, such as Néel-type domain wall(DW) and skyrmions. It has been reported that the interfacial DMI originating from Rashba spin–orbit coupling(SOC) can be linearly tuned with strong external electric fields. In this work, we experimentally demonstrate that the strength of DMI exhibits rapid fluctuations, ranging from 10% to 30% of its original value, as a function of applied electric fields in Pt/Co/MgO heterostructures within the small field regime(< 10-2V/nm). Brillouin light scattering(BLS) experiments have been performed to measure DMI, and first-principles calculations show agreement with this observation, which can be explained by the variation in orbital hybridization at the Co/MgO interface in response to the weak electric fields. Our results on voltage control of DMI(VCDMI) suggest that research related to the voltage control of magnetic anisotropy for spin–orbit torque or the motion control of skyrmions might also have to consider the role of the external electric field on DMI as small voltages are generally used for the magnetoresistance detection.展开更多
Fluorine-doped tin oxide(FTO)/TiO_(2) seed layer/TiO_(2) nanorods were prepared by ion-beam deposition and hydrothermal methods.Under UV light,the photocurrent density of these nanorods was found to reach 1.39 mA/cm^(...Fluorine-doped tin oxide(FTO)/TiO_(2) seed layer/TiO_(2) nanorods were prepared by ion-beam deposition and hydrothermal methods.Under UV light,the photocurrent density of these nanorods was found to reach 1.39 mA/cm^(2),which was higher than that without the seed layer and nanorod structures.Furthermore,the FTO/TiO_(2) seed layer/TiO_(2) nanorods can also absorb visible light,overcoming a notable problem with standard TiO_(2).The photocurrent density of the FTO/TiO_(2) seed layer/TiO_(2) nanorods was found to reach 0.21 mA/cm^(2) under visible light.This high-performance results from the deposition of the TiO_(2) seed layer,which reduces the band gap of TiO_(2).The FTO/TiO_(2) seed layer/TiO_(2) nanorods also exhibited high photodegradation ability for the organic pollutant methylene blue(MB).Within 120 min,77.3%of the MB was found to have been degraded,and the degradation rates remained almost unchanged after four cycles with the same catalyst sample.Additionally,compared with powdered photocatalysts,the FTO/TiO_(2) seed layer/TiO_(2) nanorod sample is easy to recover,requiring only rinsing with water and natural drying after the reaction.展开更多
Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequenci...Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequencies of SAW devices are typically limited to within a few gigahertz, which severely restricts their applications in 5G communication, precision sensing, photonics, and quantum control. To solve this critical problem, we propose a hybrid strategy that integrates a nanomanufacturing process (i.e., nanolithography) with a LiNbO_(3)/SiO_(2)/SiC heterostructure and successfully achieve a record-breaking frequency of about 44 GHz for SAW devices, in addition to large electromechanical coupling coefficients of up to 15.7%. We perform a theoretical analysis and identify the guided higher order wave modes generated on these slow-on-fast SAW platforms. To demonstrate the superior sensing performance of the proposed ultra-high-frequency SAW platforms, we perform micro-mass sensing and obtain an extremely high sensitivity of approximately 33151.9 MHz·mm2·μg−1, which is about 1011 times higher than that of a conventional quartz crystal microbalance (QCM) and about 4000 times higher than that of a conventional SAW device with a frequency of 978 MHz.展开更多
We have successfully demonstrated a 1 Kb spin-orbit torque(SOT)magnetic random-access memory(MRAM)multiplexer(MUX)array with remarkable performance.The 1 Kb MUX array exhibits an in-die function yield of over 99.6%.Ad...We have successfully demonstrated a 1 Kb spin-orbit torque(SOT)magnetic random-access memory(MRAM)multiplexer(MUX)array with remarkable performance.The 1 Kb MUX array exhibits an in-die function yield of over 99.6%.Additionally,it provides a sufficient readout window,with a TMR/RP_sigma%value of 21.4.Moreover,the SOT magnetic tunnel junctions(MTJs)in the array show write error rates as low as 10^(-6)without any ballooning effects or back-hopping behaviors,ensuring the write stability and reliability.This array achieves write operations in 20 ns and 1.2 V for an industrial-level temperature range from-40 to 125℃.Overall,the demonstrated array shows competitive specifications compared to the state-of-the-art works.Our work paves the way for the industrial-scale production of SOT-MRAM,moving this technology beyond R&D and towards widespread adoption.展开更多
A silicon (Si)/silicon carbide (4H-SiC) heterojunction double-trench metal-oxide-semiconductor field effect transistor (MOSFET) (HDT-MOS) with the gate-controlled tunneling effect is proposed for the first time based ...A silicon (Si)/silicon carbide (4H-SiC) heterojunction double-trench metal-oxide-semiconductor field effect transistor (MOSFET) (HDT-MOS) with the gate-controlled tunneling effect is proposed for the first time based on simulations. In this structure, the channel regions are made of Si to take advantage of its high channel mobility and carrier density. The voltage-withstanding region is made of 4H-SiC so that HDT-MOS has a high breakdown voltage (BV) similar to pure 4H-SiC double-trench MOSFETs (DT-MOSs). The gate-controlled tunneling effect indicates that the gate voltage (V_(G)) has a remarkable influence on the tunneling current of the heterojunction. The accumulation layer formed with positive VG can reduce the width of the Si/SiC heterointerface barrier, similar to the heavily doped region in an Ohmic contact. This narrower barrier is easier for electrons to tunnel through, resulting in a lower heterointerface resistance. Thus, with similar BV (approximately 1770 V), the specific on-state resistance (R_(ON-SP)) of HDT-MOS is reduced by 0.77 mΩ·cm^(2) compared with that of DT-MOS. The gate-to-drain charge (Q_(GD)) and switching loss of HDT-MOS are 52.14% and 22.59% lower than those of DT-MOS, respectively, due to the lower gate platform voltage (V_(GP)) and the corresponding smaller variation (ΔV_(GP)). The figure of merit (Q_(GD)×R_(ON-SP)) of HDT-MOS decreases by 61.25%. Moreover, the heterointerface charges can reduce RON-SP of HDT-MOS due to trap-assisted tunneling while the heterointerface traps show the opposite effect. Therefore, the HDT-MOS structure can significantly reduce the working loss of SiC MOSFET, leading to a lower temperature rise when the devices are applied in the system.展开更多
We investigate asymmetric spin wave scattering behaviors caused by vortex chirality in a cross-shaped ferromagnetic system by using the micromagnetic simulations.In the system,four scattering behaviors are found:(i)as...We investigate asymmetric spin wave scattering behaviors caused by vortex chirality in a cross-shaped ferromagnetic system by using the micromagnetic simulations.In the system,four scattering behaviors are found:(i)asymmetric skew scattering,depending on the polarity of vortex core,(ii)back scattering(reflection),depending on the vortex core stiffness,(iii)side deflection scattering,depending on structural symmetry of the vortex circulation,and(iv)geometrical scattering,depending on waveguide structure.The first and second scattering behaviors are attributed to nonlinear topological magnon spin Hall effect related to magnon spin-transfer torque effect,which has value for magnonic exploration and application.展开更多
Chemical vapor deposition is considered as the most hopeful method for the synthesis of large-area high-quality hexagonal boron nitride on the substrate of catalytic metal. However, the size the hexagonal boron nitrid...Chemical vapor deposition is considered as the most hopeful method for the synthesis of large-area high-quality hexagonal boron nitride on the substrate of catalytic metal. However, the size the hexagonal boron nitride films are limited to the size of growth chamber, which indicates a lower production efficiency. In this paper, the utilization efficiency of growth chamber is highly improved by alternately stacking multiple pieces of Cu foils and carbon fiber surface felt with porous structure. Uniform and continuous hexagonal boron nitride films are prepared on Cu foils through chemical vapor deposition utilizing ammonia borane as the precursor. This work develops a simple and practicable method for high-throughput preparation of hexagonal boron nitride films, which could contribute to the industrial application of hexagonal boron nitride. .展开更多
A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic clocks.The proposed power stabilization loop(PSL...A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic clocks.The proposed power stabilization loop(PSL)technique,incorporating an off-chip power detector(PD),ensures that the output power of the FS-SoC remains stable,mitigating the impact of power fluctuations on the atomic clock's stability.Additionally,a one-pulse-per-second(1PPS)is employed to syn-chronize the clock with GPS.Fabricated using 65 nm CMOS technology,the measured phase noise of the FS-SoC stands at-69.5 dBc/Hz@100 Hz offset and-83.9 dBc/Hz@1 kHz offset,accompanied by a power dissipation of 19.7 mW.The Cs atomic clock employing the proposed FS-SoC and PSL obtains an Allan deviation of 1.7×10^(-11) with 1-s averaging time.展开更多
Web application fingerprint recognition is an effective security technology designed to identify and classify web applications,thereby enhancing the detection of potential threats and attacks.Traditional fingerprint r...Web application fingerprint recognition is an effective security technology designed to identify and classify web applications,thereby enhancing the detection of potential threats and attacks.Traditional fingerprint recognition methods,which rely on preannotated feature matching,face inherent limitations due to the ever-evolving nature and diverse landscape of web applications.In response to these challenges,this work proposes an innovative web application fingerprint recognition method founded on clustering techniques.The method involves extensive data collection from the Tranco List,employing adjusted feature selection built upon Wappalyzer and noise reduction through truncated SVD dimensionality reduction.The core of the methodology lies in the application of the unsupervised OPTICS clustering algorithm,eliminating the need for preannotated labels.By transforming web applications into feature vectors and leveraging clustering algorithms,our approach accurately categorizes diverse web applications,providing comprehensive and precise fingerprint recognition.The experimental results,which are obtained on a dataset featuring various web application types,affirm the efficacy of the method,demonstrating its ability to achieve high accuracy and broad coverage.This novel approach not only distinguishes between different web application types effectively but also demonstrates superiority in terms of classification accuracy and coverage,offering a robust solution to the challenges of web application fingerprint recognition.展开更多
The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To ad...The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,Fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic activity.Precisely,atomically dispersed Fe-N_(x) sites supported on N/S-doped mesoporous carbon(NSC)coupled with FeS@C core-shell nanoparticles(FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis.Due to the presence of an in situ-grown conductive graphitic layer(shell),the FeS nanoparticles(core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions.Consequently,FAS-NSC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAS-NSC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based ZAB.This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR,with potential implications for energy conversion and storage technologies.展开更多
To evaluate the impact of zinc sulfate(ZnSO_(4)) concentration on the structural properties of the films,Cd_(1-x)Zn_(x)S thin films were formed on glass substrates using chemical bath deposition(CBD) in this study.The...To evaluate the impact of zinc sulfate(ZnSO_(4)) concentration on the structural properties of the films,Cd_(1-x)Zn_(x)S thin films were formed on glass substrates using chemical bath deposition(CBD) in this study.The effect of ZnSO_(4) precursor concentration on the surface morphology,optical properties,and morphological structure of the Cd_(1-x)Zn_(x)S films was investigated.To study the impact of zinc doping content on the performance metrics of Cu(In_(1-x)Ga_(x))Se_(2)(CIGS)cells in the experimental group and to improve the buffer layer thickness,simulations were run using one-dimensional solar cell capacitance simulator(SCAPS-1D) software.展开更多
Chemical vapor deposition(CVD)is the most promising method for the preparation of high-quality and large-area graphene films,especially the epitaxial growth of graphene on large-area single-crystal Cu foils.While sing...Chemical vapor deposition(CVD)is the most promising method for the preparation of high-quality and large-area graphene films,especially the epitaxial growth of graphene on large-area single-crystal Cu foils.While single-crystal Cu foils are normally achieved by thermally annealing the commercial poly-crystalline Cu foils,their size and therefore the size of graphene films grown on them are limited to the size of the reaction chamber.We report a simple and feasible method to prepare large-area Cu foils with decimeter grains by thermally annealing the rolled-up Cu foils,where the Cu layers are separated by thin porous carbon fiber cloths.The carbon fiber cloths prevent Cu layers from sticking to each other at high temperatures while do not block the gas transportation.In such a way,the utilization efficiency of the reaction chamber is significantly improved,e.g.,0.2 m×(1e2)m Cu foils can be processed even in a 5 cm diameter quartz tube chamber.High-quality graphene films grown on such Cu foils are then demon-strated.This method may be suitable for the annealing of other metal foils to enlarge grain size and the synthesis of other two-dimensional materials on them such as h-BN.展开更多
Spin-orbit torque(SOT)has been considered as one of the promising technologies for the next-generation magnetic random access memory(MRAM).So far,SOT has been widely utilized for inducing various modes of magnetizatio...Spin-orbit torque(SOT)has been considered as one of the promising technologies for the next-generation magnetic random access memory(MRAM).So far,SOT has been widely utilized for inducing various modes of magnetization switching.However,it is a challenge that so many multiple modes of magnetization switching are integrated together.Here we propose a method of implementing both unipolar switching and bipolar switching of the perpendicular magnetization within a single SOT device.The mode of switching can be easily changed by tuning the amplitude of the applied current.We show that the field-like torque plays an important role in switching process.The field-like torque induces the precession of the magnetization in the case of unipolar switching,however,the field-like torque helps to generate an effective zcomponent torque in the case of bipolar switching.In addition,the influence of key parameters on the mode of switching is discussed,including the field-like torque strength,the bias field,and the current density.Our proposal can be used to design novel reconfigurable logic circuits in the near future.展开更多
In this paper,Cd1-xZnxS thin films were prepared by chemical bath deposition(CBD),and the effects of different zinc doping content on the morphological structure and optical properties of Cd1-xZnxS buffer layers are s...In this paper,Cd1-xZnxS thin films were prepared by chemical bath deposition(CBD),and the effects of different zinc doping content on the morphological structure and optical properties of Cd1-xZnxS buffer layers are systematically discussed.The experimental results show that in the deposition process of different substrates,the crystal structure of the film is all hexagonal,and when the concentration of zinc sulfate(ZnSO4)precursor is varied from 0 to 0.025 M,the films are uniform and dense.With the increase of zinc content,the X-ray diffraction(XRD)peak of the films shifted behind that of CdS film(002).It showed 70%to 90%transmittance in the visible region and the optical band gap increased gradually.The band gap value of the films obtained ranged from 2.43 eV to 3.01 eV.It shows the potential feasibility of its application to photovoltaic devices.展开更多
The effects of different preheating and annealing temperatures on the surface morphology,microstructure,and optical properties of Cu_(2)ZnSnS_(4)(CZTS) thin films are investigated by controlling the preheating and ann...The effects of different preheating and annealing temperatures on the surface morphology,microstructure,and optical properties of Cu_(2)ZnSnS_(4)(CZTS) thin films are investigated by controlling the preheating and annealing temperatures.The prepared thin films were characterized using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),and ultra-violet-visible(UV-Vis) spectroscopy techniques.XRD and Raman spectroscopy showed that a Kesterite structure with a selective orientation along the(112) peak was generated,and the thin films produced at a preheating temperature of 300℃ and annealing temperature of 570℃ had fewer secondary phases,which was beneficial for improving the performance of the solar cells.SEM confirms that the crystallite size increases and then decreases as the temperature increases,and the largest and most uniform crystallite size with the smoothest surface is generated at the above preheating and annealing temperatures.UV-Vis measurements show that the thin films generated at the above temperature have the lowest transmittance and the lowest optical band gap value of 1.46 e V,which is close to the optimal band gap value for solar cells and is suitable as an absorber layer material.展开更多
文摘This Special Topic of the Journal of Semiconductors(JoS)features expanded versions of key articles presented at the 2023 IEEE International Conference on Integrated Circuits Technologies and Applications(ICTA),which was held in Hefei,Anhui,China,from October 27 to 29,2023.IEEE ICTA is an IEEE flagship conference in the field of integrated circuits(IC)in China,which provides a communication platform for sharing the state-of-the-art techniques from experts in the field of ICs.Among the 93 papers presented at ICTA 2023,the Technical Program Committee and the Award Committee have selected 4 high-quality articles to recommend to the Special Topic of JoS,covering a wide range of technical fields,including one paper on RF ICs,two papers on Analog ICs and one paper on Wireline ICs.
基金the Tencent Foundation through the XPLORER PRIZEthe National Key Research and Development Program of China(Grant Nos.2018YFB0407602 and 2021YFB3601303)the National Natural Science Foundation of China(Grant Nos.61627813,11904017,92164206,and 61571023)。
文摘Topological magnetotransport in non-collinear antiferromagnets has attracted extensive attention due to the exotic phenomena such as large anomalous Hall effect(AHE),magnetic spin Hall effect,and chiral anomaly.The materials exhibiting topological antiferromagnetic physics are typically limited in special Mn_3X family such as Mn_3Sn and Mn_3Ge.Exploring the topological magnetotransport in common antiferromagnetic materials widely used in spintronics will not only enrich the platforms for investigating the non-collinear antiferromagnetic physics,but also have great importance for driving the nontrivial topological properties towards practical applications.Here,we report remarkable AHE,anisotropic and negative parallel magnetoresistance in the magnetron-sputtered Ir_(20)Mn_(80)antiferromagnet,which is one of the most widely used antiferromagnetic materials in industrial spintronics.The ab initio calculations suggest that the Ir_4Mn_(16)(IrMn_4)or Mn_3Ir nanocrystals hold nontrivial electronic band structures,which may contribute to the observed intriguing magnetotransport properties in the Ir_(20)Mn_(80).Further,we demonstrate the spin–orbit torque switching of the antiferromagnetic Ir_(20)Mn_(80)by the spin Hall current of Pt.The presented results highlight a great potential of the magnetron-sputtered Ir_(20)Mn_(80)film for exploring the topological antiferromagnet-based physics and spintronics applications.
文摘An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a source-FP.The equivalent circuit of the overall model is composed of parasitic elements,intrinsic transistors,gate-FP,and source-FP networks.The equivalent circuit of the gate-FP is identical to that of the intrinsic transistor.In order to simplify the complexity of the model,a series combination of a resistor and a capacitor is employed to represent the source-FP.The analytical extraction procedure of the model parameters is presented based on the proposed equivalent circuit.The verification is carried out on a 4×250μm GaN HEMT device with a gate-FP and a source-FP in a 0.45μm technology.Compared with the classic model,the proposed novel small-signal model shows closer agreement with measured S-parameters in the range of 1.0 to 18.0 GHz.
文摘A comprehensive investigation was conducted to explore the degradation mechanism of leakage current in SiC junction barrier Schottky(JBS)diodes under heavy ion irradiation.We propose and verify that the generation of stacking faults(SFs)induced by the recombination of massive electron-hole pairs during irradiation is the cause of reverse leakage current degradation based on experiments results.The irradiation experiment was carried out based on Ta ions with high linear energy transfer(LET)of 90.5 MeV/(mg/cm^(2)).It is observed that the leakage current of the diode undergoes the permanent increase during irradiation when biased at 20%of the rated reverse voltage.Micro-PL spectroscopy and PL micro-imaging were utilized to detect the presence of SFs in the irradiated SiC JBS diodes.We combined the degraded performance of irradiated samples with SFs introduced by heavy ion irradiation.Finally,three-dimensional(3D)TCAD simulation was employed to evaluate the excessive electron-hole pairs(EHPs)concentration excited by heavy ion irradiation.It was observed that the excessive hole concentration under irradiation exceeded significantly the threshold hole concentration necessary for the expansion of SFs in the substrate.The proposed mechanism suggests that the process and material characteristics of the silicon carbide should be considered in order to reinforcing against the single event effect of SiC power devices.
基金supported by the open research fund of Songshan Lake Materials Laboratory (2022SLABFN26)the National Natural Science Foundation of China (21773024)+1 种基金the Sichuan Science and Technology program (2020YJ0324,2020YJ0262)the Reformation and Development Funds for Local Region Universities from China Government in 2020 (ZCKJ 2020-11)。
文摘The shuttle effect of lithium polysulfides(LiPSs)and uncontrollable lithium dendrite growth seriously hinder the practical application of lithium-sulfur(Li-S)batteries.To simultaneously address such issues,monodispersed Nb N quantum dots anchored on nitrogen-doped hollow carbon nanorods(NbN@NHCR)are elaborately developed as efficient Li PSs immobilizer and Li stabilizer for high-performance Li-S full batteries.Density functional theory(DFT)calculations and experimental characterizations demonstrate that the sulfiphilic and lithiophilic NbN@NHCR hybrid can not only efficiently immobilize the soluble Li PSs and facilitate diffusion-conversion kinetics for alleviating the shuttling effect,but also homogenize the distribution of Li+ions and regulate uniform Li deposition for suppressing Li-dendrite growth.As a result,the assembled Li-S full batteries(NbN@NHCR-S||Nb N@NHCR-Li)deliver excellent long-term cycling stability with a low decay rate of 0.031%per cycle over 1000 cycles at high rate of 2 C.Even at a high S loading of 5.8 mg cm^(-2)and a low electrolyte/sulfur ratio of 5.2μL mg^(-1),a large areal capacity of 6.2 mA h cm^(-2)can be achieved in Li-S pouch cell at 0.1 C.This study provides a new perspective via designing a dual-functional sulfiphilic and lithiophilic hybrid to address serious issues of the shuttle effect of S cathode and dendrite growth of Li anode.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61627813,62204018,and 61571023)the Beijing Municipal Science and Technology Project(Grant No.Z201100004220002)+2 种基金the National Key Technology Program of China(Grant No.2017ZX01032101)the Program of Introducing Talents of Discipline to Universities in China(Grant No.B16001)the VR Innovation Platform from Qingdao Science and Technology Commission.
文摘Dzyaloshinskii–Moriya interaction(DMI) is under extensive investigation considering its crucial status in chiral magnetic orders, such as Néel-type domain wall(DW) and skyrmions. It has been reported that the interfacial DMI originating from Rashba spin–orbit coupling(SOC) can be linearly tuned with strong external electric fields. In this work, we experimentally demonstrate that the strength of DMI exhibits rapid fluctuations, ranging from 10% to 30% of its original value, as a function of applied electric fields in Pt/Co/MgO heterostructures within the small field regime(< 10-2V/nm). Brillouin light scattering(BLS) experiments have been performed to measure DMI, and first-principles calculations show agreement with this observation, which can be explained by the variation in orbital hybridization at the Co/MgO interface in response to the weak electric fields. Our results on voltage control of DMI(VCDMI) suggest that research related to the voltage control of magnetic anisotropy for spin–orbit torque or the motion control of skyrmions might also have to consider the role of the external electric field on DMI as small voltages are generally used for the magnetoresistance detection.
基金This work was supported by Tianjin Natural Science Foundation(Grant No.19JCQNJC06200)Major Projects of Science and Technology in Tianjin(Grant No.18ZXJMTG00020).
文摘Fluorine-doped tin oxide(FTO)/TiO_(2) seed layer/TiO_(2) nanorods were prepared by ion-beam deposition and hydrothermal methods.Under UV light,the photocurrent density of these nanorods was found to reach 1.39 mA/cm^(2),which was higher than that without the seed layer and nanorod structures.Furthermore,the FTO/TiO_(2) seed layer/TiO_(2) nanorods can also absorb visible light,overcoming a notable problem with standard TiO_(2).The photocurrent density of the FTO/TiO_(2) seed layer/TiO_(2) nanorods was found to reach 0.21 mA/cm^(2) under visible light.This high-performance results from the deposition of the TiO_(2) seed layer,which reduces the band gap of TiO_(2).The FTO/TiO_(2) seed layer/TiO_(2) nanorods also exhibited high photodegradation ability for the organic pollutant methylene blue(MB).Within 120 min,77.3%of the MB was found to have been degraded,and the degradation rates remained almost unchanged after four cycles with the same catalyst sample.Additionally,compared with powdered photocatalysts,the FTO/TiO_(2) seed layer/TiO_(2) nanorod sample is easy to recover,requiring only rinsing with water and natural drying after the reaction.
基金supported by the National Science Foundation of China(NSFC)(52075162)the Program of New and High-Tech Industry of Hunan Province(2020GK2015 and 2021GK4014)+5 种基金the Excellent Youth Fund of Hunan Province(2021JJ20018)the Key Program of Guangdong(2020B0101040002)the Joint Fund of the Ministry of Education(Young Talents)the Natural Science Foundation of Changsha(kq2007026)the Tianjin Enterprise Science and Technology Commissioner Project(19JCTPJC56200)the Engineering Physics and Science Research Council of the United Kingdom(EPSRC EP/P018998/1).
文摘Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequencies of SAW devices are typically limited to within a few gigahertz, which severely restricts their applications in 5G communication, precision sensing, photonics, and quantum control. To solve this critical problem, we propose a hybrid strategy that integrates a nanomanufacturing process (i.e., nanolithography) with a LiNbO_(3)/SiO_(2)/SiC heterostructure and successfully achieve a record-breaking frequency of about 44 GHz for SAW devices, in addition to large electromechanical coupling coefficients of up to 15.7%. We perform a theoretical analysis and identify the guided higher order wave modes generated on these slow-on-fast SAW platforms. To demonstrate the superior sensing performance of the proposed ultra-high-frequency SAW platforms, we perform micro-mass sensing and obtain an extremely high sensitivity of approximately 33151.9 MHz·mm2·μg−1, which is about 1011 times higher than that of a conventional quartz crystal microbalance (QCM) and about 4000 times higher than that of a conventional SAW device with a frequency of 978 MHz.
基金supported by the National Key Research and Development Program of China (Nos.2021YFB3601303,2021YFB3601304,2021YFB3601300,2022YFB4400200,2022YFB4400201,2022YFB4400203)the National Natural Science Foundation of China (Grant No.62171013)。
文摘We have successfully demonstrated a 1 Kb spin-orbit torque(SOT)magnetic random-access memory(MRAM)multiplexer(MUX)array with remarkable performance.The 1 Kb MUX array exhibits an in-die function yield of over 99.6%.Additionally,it provides a sufficient readout window,with a TMR/RP_sigma%value of 21.4.Moreover,the SOT magnetic tunnel junctions(MTJs)in the array show write error rates as low as 10^(-6)without any ballooning effects or back-hopping behaviors,ensuring the write stability and reliability.This array achieves write operations in 20 ns and 1.2 V for an industrial-level temperature range from-40 to 125℃.Overall,the demonstrated array shows competitive specifications compared to the state-of-the-art works.Our work paves the way for the industrial-scale production of SOT-MRAM,moving this technology beyond R&D and towards widespread adoption.
基金the Major Science and Technology Program of Anhui Province under Grant No.2020b05050007.
文摘A silicon (Si)/silicon carbide (4H-SiC) heterojunction double-trench metal-oxide-semiconductor field effect transistor (MOSFET) (HDT-MOS) with the gate-controlled tunneling effect is proposed for the first time based on simulations. In this structure, the channel regions are made of Si to take advantage of its high channel mobility and carrier density. The voltage-withstanding region is made of 4H-SiC so that HDT-MOS has a high breakdown voltage (BV) similar to pure 4H-SiC double-trench MOSFETs (DT-MOSs). The gate-controlled tunneling effect indicates that the gate voltage (V_(G)) has a remarkable influence on the tunneling current of the heterojunction. The accumulation layer formed with positive VG can reduce the width of the Si/SiC heterointerface barrier, similar to the heavily doped region in an Ohmic contact. This narrower barrier is easier for electrons to tunnel through, resulting in a lower heterointerface resistance. Thus, with similar BV (approximately 1770 V), the specific on-state resistance (R_(ON-SP)) of HDT-MOS is reduced by 0.77 mΩ·cm^(2) compared with that of DT-MOS. The gate-to-drain charge (Q_(GD)) and switching loss of HDT-MOS are 52.14% and 22.59% lower than those of DT-MOS, respectively, due to the lower gate platform voltage (V_(GP)) and the corresponding smaller variation (ΔV_(GP)). The figure of merit (Q_(GD)×R_(ON-SP)) of HDT-MOS decreases by 61.25%. Moreover, the heterointerface charges can reduce RON-SP of HDT-MOS due to trap-assisted tunneling while the heterointerface traps show the opposite effect. Therefore, the HDT-MOS structure can significantly reduce the working loss of SiC MOSFET, leading to a lower temperature rise when the devices are applied in the system.
基金Project supported by the Basic Science Research Program of the National Research Foundation of Korea(Grant No.2021R1F1A1050539)the Yanbian University Research Project(Grant No.482022104)the Yichang Natural Science Research Project(Grant No.A22-3-010)。
文摘We investigate asymmetric spin wave scattering behaviors caused by vortex chirality in a cross-shaped ferromagnetic system by using the micromagnetic simulations.In the system,four scattering behaviors are found:(i)asymmetric skew scattering,depending on the polarity of vortex core,(ii)back scattering(reflection),depending on the vortex core stiffness,(iii)side deflection scattering,depending on structural symmetry of the vortex circulation,and(iv)geometrical scattering,depending on waveguide structure.The first and second scattering behaviors are attributed to nonlinear topological magnon spin Hall effect related to magnon spin-transfer torque effect,which has value for magnonic exploration and application.
文摘Chemical vapor deposition is considered as the most hopeful method for the synthesis of large-area high-quality hexagonal boron nitride on the substrate of catalytic metal. However, the size the hexagonal boron nitride films are limited to the size of growth chamber, which indicates a lower production efficiency. In this paper, the utilization efficiency of growth chamber is highly improved by alternately stacking multiple pieces of Cu foils and carbon fiber surface felt with porous structure. Uniform and continuous hexagonal boron nitride films are prepared on Cu foils through chemical vapor deposition utilizing ammonia borane as the precursor. This work develops a simple and practicable method for high-throughput preparation of hexagonal boron nitride films, which could contribute to the industrial application of hexagonal boron nitride. .
基金supported by the National Natural Science Foundation of China under Grant 62034002 and 62374026.
文摘A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic clocks.The proposed power stabilization loop(PSL)technique,incorporating an off-chip power detector(PD),ensures that the output power of the FS-SoC remains stable,mitigating the impact of power fluctuations on the atomic clock's stability.Additionally,a one-pulse-per-second(1PPS)is employed to syn-chronize the clock with GPS.Fabricated using 65 nm CMOS technology,the measured phase noise of the FS-SoC stands at-69.5 dBc/Hz@100 Hz offset and-83.9 dBc/Hz@1 kHz offset,accompanied by a power dissipation of 19.7 mW.The Cs atomic clock employing the proposed FS-SoC and PSL obtains an Allan deviation of 1.7×10^(-11) with 1-s averaging time.
基金supported in part by the National Science Foundation of China under Grants U22B2027,62172297,62102262,61902276 and 62272311,Tianjin Intelligent Manufacturing Special Fund Project under Grant 20211097the China Guangxi Science and Technology Plan Project(Guangxi Science and Technology Base and Talent Special Project)under Grant AD23026096(Application Number 2022AC20001)+1 种基金Hainan Provincial Natural Science Foundation of China under Grant 622RC616CCF-Nsfocus Kunpeng Fund Project under Grant CCF-NSFOCUS202207.
文摘Web application fingerprint recognition is an effective security technology designed to identify and classify web applications,thereby enhancing the detection of potential threats and attacks.Traditional fingerprint recognition methods,which rely on preannotated feature matching,face inherent limitations due to the ever-evolving nature and diverse landscape of web applications.In response to these challenges,this work proposes an innovative web application fingerprint recognition method founded on clustering techniques.The method involves extensive data collection from the Tranco List,employing adjusted feature selection built upon Wappalyzer and noise reduction through truncated SVD dimensionality reduction.The core of the methodology lies in the application of the unsupervised OPTICS clustering algorithm,eliminating the need for preannotated labels.By transforming web applications into feature vectors and leveraging clustering algorithms,our approach accurately categorizes diverse web applications,providing comprehensive and precise fingerprint recognition.The experimental results,which are obtained on a dataset featuring various web application types,affirm the efficacy of the method,demonstrating its ability to achieve high accuracy and broad coverage.This novel approach not only distinguishes between different web application types effectively but also demonstrates superiority in terms of classification accuracy and coverage,offering a robust solution to the challenges of web application fingerprint recognition.
基金financially supported by the National Natural Science Foundation of China(21773024)the Natural Science Foundation of Sichuan Province of China(2023NSFC0084)the China Postdoctoral Science Foundation(2019M663469)。
文摘The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,Fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic activity.Precisely,atomically dispersed Fe-N_(x) sites supported on N/S-doped mesoporous carbon(NSC)coupled with FeS@C core-shell nanoparticles(FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis.Due to the presence of an in situ-grown conductive graphitic layer(shell),the FeS nanoparticles(core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions.Consequently,FAS-NSC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAS-NSC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based ZAB.This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR,with potential implications for energy conversion and storage technologies.
基金supported by the Science and Technology Innovation Development Program (No.70304901)。
文摘To evaluate the impact of zinc sulfate(ZnSO_(4)) concentration on the structural properties of the films,Cd_(1-x)Zn_(x)S thin films were formed on glass substrates using chemical bath deposition(CBD) in this study.The effect of ZnSO_(4) precursor concentration on the surface morphology,optical properties,and morphological structure of the Cd_(1-x)Zn_(x)S films was investigated.To study the impact of zinc doping content on the performance metrics of Cu(In_(1-x)Ga_(x))Se_(2)(CIGS)cells in the experimental group and to improve the buffer layer thickness,simulations were run using one-dimensional solar cell capacitance simulator(SCAPS-1D) software.
基金supported by National Natural Science Founda-tion of China(No.52172138)Shenzhen Science and Technology Program(No.(2021)105).
文摘Chemical vapor deposition(CVD)is the most promising method for the preparation of high-quality and large-area graphene films,especially the epitaxial growth of graphene on large-area single-crystal Cu foils.While single-crystal Cu foils are normally achieved by thermally annealing the commercial poly-crystalline Cu foils,their size and therefore the size of graphene films grown on them are limited to the size of the reaction chamber.We report a simple and feasible method to prepare large-area Cu foils with decimeter grains by thermally annealing the rolled-up Cu foils,where the Cu layers are separated by thin porous carbon fiber cloths.The carbon fiber cloths prevent Cu layers from sticking to each other at high temperatures while do not block the gas transportation.In such a way,the utilization efficiency of the reaction chamber is significantly improved,e.g.,0.2 m×(1e2)m Cu foils can be processed even in a 5 cm diameter quartz tube chamber.High-quality graphene films grown on such Cu foils are then demon-strated.This method may be suitable for the annealing of other metal foils to enlarge grain size and the synthesis of other two-dimensional materials on them such as h-BN.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62171013 and 61704005)the National Key Research and Development Program of China(Grant Nos.2021YFB3601303,2021YFB3601304,and 2021YFB3601300)+1 种基金the Beijing Municipal Science and Technology Project,China(Grant No.Z201100004220002)the Fundamental Research Funds for the Central Universities,China(Grant No.YWF-21-BJ-J-1043)。
文摘Spin-orbit torque(SOT)has been considered as one of the promising technologies for the next-generation magnetic random access memory(MRAM).So far,SOT has been widely utilized for inducing various modes of magnetization switching.However,it is a challenge that so many multiple modes of magnetization switching are integrated together.Here we propose a method of implementing both unipolar switching and bipolar switching of the perpendicular magnetization within a single SOT device.The mode of switching can be easily changed by tuning the amplitude of the applied current.We show that the field-like torque plays an important role in switching process.The field-like torque induces the precession of the magnetization in the case of unipolar switching,however,the field-like torque helps to generate an effective zcomponent torque in the case of bipolar switching.In addition,the influence of key parameters on the mode of switching is discussed,including the field-like torque strength,the bias field,and the current density.Our proposal can be used to design novel reconfigurable logic circuits in the near future.
基金supported by the Fund for Creative Research Groups。
文摘In this paper,Cd1-xZnxS thin films were prepared by chemical bath deposition(CBD),and the effects of different zinc doping content on the morphological structure and optical properties of Cd1-xZnxS buffer layers are systematically discussed.The experimental results show that in the deposition process of different substrates,the crystal structure of the film is all hexagonal,and when the concentration of zinc sulfate(ZnSO4)precursor is varied from 0 to 0.025 M,the films are uniform and dense.With the increase of zinc content,the X-ray diffraction(XRD)peak of the films shifted behind that of CdS film(002).It showed 70%to 90%transmittance in the visible region and the optical band gap increased gradually.The band gap value of the films obtained ranged from 2.43 eV to 3.01 eV.It shows the potential feasibility of its application to photovoltaic devices.
基金supported by the Tianjin Municipal Education Commission (No.70304901)。
文摘The effects of different preheating and annealing temperatures on the surface morphology,microstructure,and optical properties of Cu_(2)ZnSnS_(4)(CZTS) thin films are investigated by controlling the preheating and annealing temperatures.The prepared thin films were characterized using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),and ultra-violet-visible(UV-Vis) spectroscopy techniques.XRD and Raman spectroscopy showed that a Kesterite structure with a selective orientation along the(112) peak was generated,and the thin films produced at a preheating temperature of 300℃ and annealing temperature of 570℃ had fewer secondary phases,which was beneficial for improving the performance of the solar cells.SEM confirms that the crystallite size increases and then decreases as the temperature increases,and the largest and most uniform crystallite size with the smoothest surface is generated at the above preheating and annealing temperatures.UV-Vis measurements show that the thin films generated at the above temperature have the lowest transmittance and the lowest optical band gap value of 1.46 e V,which is close to the optimal band gap value for solar cells and is suitable as an absorber layer material.
