Perovskite solar cells(PSCs)emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world.Both the efficiency and stability of PSC...Perovskite solar cells(PSCs)emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world.Both the efficiency and stability of PSCs have increased steadily in recent years,and the research on reducing lead leakage and developing eco-friendly lead-free perovskites pushes forward the commercialization of PSCs step by step.This review summarizes the main progress of PSCs in 2020 and 2021 from the aspects of efficiency,stability,perovskite-based tandem devices,and lead-free PSCs.Moreover,a brief discussion on the development of PSC modules and its challenges toward practical application is provided.展开更多
Nitrogen-doped three-dimensional graphene(N-doped 3D-graphene)is a graphene derivative with excellent adsorption capacity,large specific surface area,high porosity,and optoelectronic properties.Herein,N-doped 3D-graph...Nitrogen-doped three-dimensional graphene(N-doped 3D-graphene)is a graphene derivative with excellent adsorption capacity,large specific surface area,high porosity,and optoelectronic properties.Herein,N-doped 3D-graphene/Si heterojunctions were grown in situ directly on silicon(Si)substrates via plasma-assisted chemical vapor deposition(PACVD),which is promising for surface-enhanced Raman scattering(SERS)substrates candidates.Combined analyses of theoretical simulation,incorporating N atoms in 3D-graphene are beneficial to increase the electronic state density of the system and enhance the charge transfer between the substrate and the target molecules.The enhancement of the optical and electric fields benefits from the stronger light-matter interaction improved by the natural nano-resonator structure of N-doped 3D-graphene.The as-prepared SERS substrates based on N-doped 3D-graphene/Si heterojunctions achieve ultra-low detection for various molecules:10^(-8)M for methylene blue(MB)and 10^(-9)M for crystal violet(CRV)with rhodamine(R6G)of 10^(10)M.In practical detected,10^(-8)M thiram was precisely detected in apple peel extract.The results indicate that N-doped 3D-graphene/Si heterojunctions based-SERS substrates have promising applications in low-concentration molecular detection and food safety.展开更多
Human beings perceive the world through the senses of sight,hearing,smell,taste,touch,space,and balance.The first five senses are prerequisites for people to live.The sensing organs upload information to the nervous s...Human beings perceive the world through the senses of sight,hearing,smell,taste,touch,space,and balance.The first five senses are prerequisites for people to live.The sensing organs upload information to the nervous systems,including the brain,for interpreting the surrounding environment.Then,the brain sends commands to muscles reflexively to react to stimuli,including light,gas,chemicals,sound,and pressure.MXene,as an emerging two-dimensional material,has been intensively adopted in the applications of various sensors and actuators.In this review,we update the sensors to mimic five primary senses and actuators for stimulating muscles,which employ MXene-based film,membrane,and composite with other functional materials.First,a brief introduction is delivered for the structure,properties,and synthesis methods of MXenes.Then,we feed the readers the recent reports on the MXene-derived image sensors as artificial retinas,gas sensors,chemical biosensors,acoustic devices,and tactile sensors for electronic skin.Besides,the actuators of MXene-based composite are introduced.Eventually,future opportunities are given to MXene research based on the requirements of artificial intelligence and humanoid robot,which may induce prospects in accompanying healthcare and biomedical engineering applications.展开更多
Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of ...Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of the selection of materials and the response to external fields is essential for attaining desired functionality of a GMM.Herein,machine learning(ML)models are conducted to predict saturation magnetostrictions(λ_(s))in RFe_(2)-type(R=rare earth)GMMs with different compositions.According to ML-predicted composition–λsrelations,it is discovered that the values ofλshigher than1100×10^(-6)are almost situated in the composition space surrounded by 0.26≤x≤0.60 and 1.90≤y≤2.00 for the ternary compounds of Tb_(x)Dy_(1-x)Fe_(y).Assisted by ML predictions,the compositions are further narrowed down to the space surrounded by 0.26≤x≤0.32 and 1.92≤y≤1.97 for the excellent piezomagnetic(PM)performance in the Tb_(x)Dy_(1-x)Fe_(y)based PM device through our developed high-throughput(HTP)micromagnetic simulation(MMS)algorithm.Accordingly,high sensitivities up to10.22-13.61 m T·MPa^(-1)are observed in the optimized range within which the available experimental data fall well.This work not only provides valuable insights toward understanding the mechanism of magnetoelastic couplings,but also paves the way for designing and optimizing highperformance magnetostrictive materials and PM sensing devices.展开更多
Flexible memristor devices based on plastic substrates have attracted considerable attention due to their applications in wearable computers and integrated circuits. However, most plastic-substrate memristors cannot f...Flexible memristor devices based on plastic substrates have attracted considerable attention due to their applications in wearable computers and integrated circuits. However, most plastic-substrate memristors cannot function or be grown in high-temperature environments. In this study, scotch-tape-exfoliated mica was used as the flexible memristor substrate in order to resolve these high-temperature issues. Our TiN/ZHO/IGZO memristor, which was constructed using a thin （10 μm） mica substrate, has superior flexibility and thermostability. After bending it 103 times, the device continues to exhibit exceptional electrical characteristics. It can also be implemented for transitions between high and low resistance states, even in temperatures of up to 300 ℃. More importantly, the biological synaptic characteristics of paired-pulse facilitation/depression （PPF/PPD） and spike- timing-dependent plasticity （STDP） were observed through applying different pulse measurement modes. This work demonstrates that flexible memristor devices on mica substrates may potentially allow for the realization of high-temperature memristor applications for biologically-inspired computing systems.展开更多
Photodetectors(PDs)play a crucial role in imaging,sensing,communication systems,etc.Graphene(Gr),a leading two-dimensional material,has demonstrated significant potential for photodetection in recent years.However,its...Photodetectors(PDs)play a crucial role in imaging,sensing,communication systems,etc.Graphene(Gr),a leading two-dimensional material,has demonstrated significant potential for photodetection in recent years.However,its relatively weak interaction with light poses challenges for practical applications.The integration of silicon(Si)and perovskite quantum dots(PQDs)has opened new avenues for Gr in the realm of next-generation optoelectronics.This review provides a comprehensive investigation of Gr/Si Schottky junction PDs and Gr/PQD hybrid PDs as well as their heterostructures.The operating principles,design,fabrication,optimization strategies,and typical applications of these devices are studied and summarized.Through these discussions,we aim to illuminate the current challenges and offer insights into future directions in this rapidly evolving field.展开更多
As a promising ultra-wide bandgap semiconductor, gallium oxide(Ga_2O_3) has attracted increasing attention in recent years. The high theoretical breakdown electrical field(8 MV/cm), ultra-wide bandgap(～ 4.8 eV) and l...As a promising ultra-wide bandgap semiconductor, gallium oxide(Ga_2O_3) has attracted increasing attention in recent years. The high theoretical breakdown electrical field(8 MV/cm), ultra-wide bandgap(～ 4.8 eV) and large Baliga's figure of merit(BFOM) of Ga_2O_3 make it a potential candidate material for next generation high-power electronics, including diode and field effect transistor(FET). In this paper, we introduce the basic physical properties of Ga_2O_3 single crystal, and review the recent research process of Ga_2O_3 based field effect transistors. Furthermore, various structures of FETs have been summarized and compared, and the potential of Ga_2O_3 is preliminary revealed. Finally, the prospect of the Ga_2O_3 based FET for power electronics application is analyzed.展开更多
Noble nanometals are of significance in both scientific interest and technological applications,which are usually obtained by conventional wet-chemical synthesis.Organic surfactants are always used in the synthesis to...Noble nanometals are of significance in both scientific interest and technological applications,which are usually obtained by conventional wet-chemical synthesis.Organic surfactants are always used in the synthesis to prevent unexpected overgrowth and aggregation of noble nanometals.However,the surfactants are hard to remove and may interfere with plasmonic and catalytic studies,remaining surfactant-free synthesis of noble nanometals a challenge.Herein,we report an approach to epitaxial growth of sizecontrolled noble nanometals on MXenes.As piloted by density functional theory calculations,along with work function experimental determination,kinetic and spectroscopic studies,epitaxial growth of noble nanometals is initiated via a mechanism that involves an in situ redox reaction.In the redox,MXenes as two-dimensional solid reductants whose work functions are compatible with the reduction potentials of noble metal cations,enable spontaneous donation of electrons from the MXenes to noble metal cations and reduce the cations into nanoscale metallic metals on the outmost surface of MXenes.Neither surfactants nor external reductants are used during the whole synthesis process,which addresses a long-standing interference issue of surfactant and external reductant in the conventional wet-chemical synthesis.Moreover,the MXenes induced noble nanometals are size-controlled.Impressively,noble nanometals firmly anchored on MXenes exhibit excellent performance towards surface enhanced Raman scattering.Our developed strategy will promote the nanostructure-controlled synthesis of noble nanometals,offering new opportunities to further improve advanced functional properties towards practical applications.展开更多
The barocaloric effect(BCE)is a promising alternative to traditional vapor compressing refrigeration because of its environmentally friendly impact and high energy efficiency.However,the driving hydrostatic pressure f...The barocaloric effect(BCE)is a promising alternative to traditional vapor compressing refrigeration because of its environmentally friendly impact and high energy efficiency.However,the driving hydrostatic pressure for most BCE materials is relatively high,which is not conducive to practical application.In this paper,we report that the large barocaloric entropy change of MnAs_(0.94)Sb_(0.06)alloy can be induced by low hydrostatic pressures.Its phase transition temperature is strongly sensitive to the applied pressure,resulting in a large barocaloric coefficient of 134 K·GPa^(-1)on cooling and 126 K·GPa^(-1)on heating.The maximum barocaloric entropy change and adiabatic temperaturechange resulted from hydrostatic pressure of 40 MPa reach up to 26.3 J·kg^(-1)·K^(-1)and 14.4 K,respectively,showing an excellent barocaloric performance.The results demonstrate that the MnAs_(0.94)Sb_(0.06)alloy is a promising alternative for BCE refrigeration.展开更多
Epilepsy is a common neurological disorder that occurs at all ages.Epilepsy not only brings physical pain to patients,but also brings a huge burden to the lives of patients and their families.At present,epilepsy detec...Epilepsy is a common neurological disorder that occurs at all ages.Epilepsy not only brings physical pain to patients,but also brings a huge burden to the lives of patients and their families.At present,epilepsy detection is still achieved through the observation of electroencephalography(EEG)by medical staff.However,this process takes a long time and consumes energy,which will create a huge workload to medical staff.Therefore,it is particularly important to realize the automatic detection of epilepsy.This paper introduces,in detail,the overall framework of EEG-based automatic epilepsy identification and the typical methods involved in each step.Aiming at the core modules,that is,signal acquisition analog front end(AFE),feature extraction and classifier selection,method summary and theoretical explanation are carried out.Finally,the future research directions in the field of automatic detection of epilepsy are prospected.展开更多
CMOS image sensors produced by the existing CMOS manufacturing process usually have difficulty achieving complete charge transfer owing to the introduction of potential barriers or Si/SiO_(2)interface state traps in t...CMOS image sensors produced by the existing CMOS manufacturing process usually have difficulty achieving complete charge transfer owing to the introduction of potential barriers or Si/SiO_(2)interface state traps in the charge transfer path,which reduces the charge transfer efficiency and image quality.Until now,scholars have only considered mechanisms that limit charge transfer from the perspectives of potential barriers and spill back effect under high illumination condition.However,the existing models have thus far ignored the charge transfer limitation due to Si/SiO_(2)interface state traps in the transfer gate channel,particularly under low illumination.Therefore,this paper proposes,for the first time,an analytical model for quantifying the incomplete charge transfer caused by Si/SiO_(2)interface state traps in the transfer gate channel under low illumination.This model can predict the variation rules of the number of untransferred charges and charge transfer efficiency when the trap energy level follows Gaussian distribution,exponential distribution and measured distribution.The model was verified with technology computer-aided design simulations,and the results showed that the simulation results exhibit the consistency with the proposed model.展开更多
Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater o...Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.展开更多
Highly sensitive and uniform three-dimensional(3D)hybrid heterogeneous structures for use in surface-enhanced Raman scattering(SERS)experiments were fabricated by sequentially decorating high-quality,ultra-clean,graph...Highly sensitive and uniform three-dimensional(3D)hybrid heterogeneous structures for use in surface-enhanced Raman scattering(SERS)experiments were fabricated by sequentially decorating high-quality,ultra-clean,graphene quantum dots(GQDs)and Ag nanoparticles(Ag-NPs)onto 3D-graphene.Finite-difference time-domain calculations and scanning Kelvin probe microscopy were used to verify that the Ag-NPs/GQDs/3D-graphene system facilitates substantial electromagnetic enhancement(due to the occurrence of two kinds of"gaps"between the Ag-NPs that form 3D"hot spots")and additional chemical enhancement(in detecting someπ-conjugated molecules).The SERS mechanism was explored in further detail via experimental analysis and confirmed by performing theoretical calculations.The large surface area of the 3D substrate(due to the large specific surface areas of the GQDs and 3D-graphene)results in a better enrichment effect which helps produce lower detection limits.In particular,the detection limits obtained using the Ag-NPs/GQDs/3D-graphene platform can reach 10^(-11)M for rhodamine 6G,10^(-10)M for methylene blue and dopamine,and 10^(-7)M for tetramethylthiuram disulfide and methyl parathion in apple juice(these are superior to most of the results reported using graphene-based SERS substrates).In summary,the 3D-platform Ag-NPs/GQDs/3D-graphene/Si shows outstanding SERS performance.It therefore has excellent application prospects in biochemical molecular detection and food safety monitoring.展开更多
An integration of single-layer proximitycoupling patch antenna and solar cells with bandwidth enhancement and optical energy harvesting is proposed for sustainable communication.For this purpose,many dual-function com...An integration of single-layer proximitycoupling patch antenna and solar cells with bandwidth enhancement and optical energy harvesting is proposed for sustainable communication.For this purpose,many dual-function components are selected for designing the miniaturized solar cell antenna.On the one hand,by greatly affecting the current flow of the rectangular patch,vias and proximity-coupling are introduced to control the resonance modes frequency and matching,respectively,for wideband application,and the radiation performance property can be achieved by high-order mode.On the other hand,vias and proximity-coupling are beneficial to complete direct-current(DC)loop of solar cell and improve compatibility of DC-RF(radio frequency),whereas a high-order mode is beneficial to increase the area of collected light energy.To prove the working principle,fabricated and manufactured solar cell antenna.The measured and simulated results illustrate that the solar cell antenna gain is raised to as high as 9.27 d Bi in4.37 to 5.06 GHz applied to fifth generation communication(5G).展开更多
Since the first demonstrations of radio-frequency(RF)circuits,the physics of the electromagnetic(EM)field and its regulation and control with codesigned circuits,have become essential competencies of RF circuit design...Since the first demonstrations of radio-frequency(RF)circuits,the physics of the electromagnetic(EM)field and its regulation and control with codesigned circuits,have become essential competencies of RF circuit designers.Leveraging advanced regulation or control methods,numerous high-performance circuits have been developed at RF and millimeter-wave(mm-wave)frequencies.Three main methods of electromagnetic regulation have been widely utilized,namely,the separation of electric and magnetic coupling paths,the manipulation of electromagnetic energy through the coupling of multiple tanks or multiple resonators,and the regulation of electromagnetic fields in air cavities or meta-substrates.The separated coupling paths of electric and magnetic fields provide guidance for designing a high-performance filter topology with a quasielliptical response through additional zeros.The manipulation of the EM field through electrical and magnetic intercouplings of multitanks or multiresonators,such as are used in oscillators,power amplifiers(PAs),etc.,results in remarkable power efficiency,size reduction,and wide bandwidth.The regulation of electromagnetism through an air cavity,patterned substrate,or metasubstrate reduces dielectric losses and size,especially when using a substrate integrated suspended line(SISL)platform.Many excellent circuits have been reported based on SISL with low loss,high integration,and self-packaging.Here,we present state-of-the-art cases that demonstrate the benefits of EM field regulation and control.展开更多
Two-dimensional(2D)Dion-Jacobson(D-J)-type cesium lead iodide CsPbI_(3) perform remarkably in terms of stability.However,the complex interactions between spacer and inorganic layers limit its excellent progress in per...Two-dimensional(2D)Dion-Jacobson(D-J)-type cesium lead iodide CsPbI_(3) perform remarkably in terms of stability.However,the complex interactions between spacer and inorganic layers limit its excellent progress in perovskite solar cells(PSCs).Herein,starting from the considerable structural diversity of organic spacers,we engineer 2D CsPbI_(3) with fine-tuning functionalities.Specifically,for the first time we embedded fluorinated aromatic cations in 2D D-J CsPbI_(3),and successfully applied it into construction of high-performance PSCs.Compared with constitutive 1,4-diaminobenzene(PDA),the fluorinated 2-fluorobenzene-1,4-diamine(F-PDA)component greatly expands the dipole moment from 0.59 D to 3.47 D,which reduces the exciton binding energy of the system.A theoretical study shows that the spacer layer and inorganic plane are more enriched with charge accumulation in(F-PDA)Csn±1 Pb_(n)I_(3n+1).The results show that(F-PDA)Csn±1Pb_(n)I_(3n+1) demonstrates more significant charge transfer between organic and inorganic layers than(PDA)Csn±1 Pb_(n)I_(3n+1),and it is confirmed in the femtosecond transient absorption experiment.Moreover,the interactions of the fluorinated spacer with the[PbI_(6)]_(4)-plane effectively manipulate the crystallization quality,and thus the ion migration and defect formation of target 2D CsPbI_(3) are inhibited.As a result,we obtained a record power conversion efficiency(PCE)beyond 15%for 2D D-J(F-PDA)Cs_(3)Pb_(4)I_(13)(n=4)PSCs with significantly improved environmental stability compared with the three-dimensional(3D)counterparts.展开更多
Poly(methyl methacrylate)(PMMA) is widely used for graphene transfer and device fabrication.However,it inevitably leaves a thin layer of polymer residues after acetone rinsing and leads to dramatic degradation of devi...Poly(methyl methacrylate)(PMMA) is widely used for graphene transfer and device fabrication.However,it inevitably leaves a thin layer of polymer residues after acetone rinsing and leads to dramatic degradation of device performance.How to eliminate contamination and restore clean surfaces of graphene is still highly demanded.In this paper,we present a reliable and position-controllable method to remove the polymer residues on graphene films by laser exposure.Under proper laser conditions,PMMA residues can be substantially reduced without introducing defects to the underlying graphene.Furthermore,by applying this laser cleaning technique to the channel and contacts of graphene fieldeffect transistors(GFETs),higher carrier mobility as well as lower contact resistance can be realized.This work opens a way for probing intrinsic properties of contaminant-free graphene and fabricating high-performance GFETs with both clean channel and intimate graphene/metal contact.展开更多
Hafnia-based ferroelectrics have greatly revived the field of ferroelectric memory(FeRAM),but certain reliability issues must be satisfactorily resolved before they can be widely applied in commercial memories.In part...Hafnia-based ferroelectrics have greatly revived the field of ferroelectric memory(FeRAM),but certain reliability issues must be satisfactorily resolved before they can be widely applied in commercial memories.In particular,the imprint phenomenon severely jeopardizes the read-out reliability in hafnia-based ferroelectric capacitors,but its origin remains unclear,which hinders the development of its recovery schemes.In this work,we have systematically investigated the imprint mechanism in TiN/Hf_(0.5)Zr_(0.5)O_(2)(HZO)/TiN ferroelectric capacitors using experiments and first-principles calculations.It is shown that carrier injection-induced charged oxygen vacancies are at the heart of imprint in HZO,where other mechanisms such as domain pinning and dead layer are less important.An imprint model based on electron de-trapping from oxygen vacancy sites has been proposed that can satisfactorily explain several experimental facts such as the strong asymmetric imprint,leakage current variation,and so forth.Based on this model,an effective imprint recovery method has been proposed,which utilizes unipolar rather than bipolar voltage inputs.The remarkable recovery performances demonstrate the prospect of improved device reliability in hafnia-based FeRAM devices.展开更多
Plasmonics could provide compact and powerful solutions for manipulating light in deep-subwavelength dimensions,which is promising for a great range of nanophotonic technologies such as plasmonic rulers and sensors.Ho...Plasmonics could provide compact and powerful solutions for manipulating light in deep-subwavelength dimensions,which is promising for a great range of nanophotonic technologies such as plasmonic rulers and sensors.However,the effective area of enhanced localized field induced by surface plasmon polaritons is typically restricted to the structural boundaries.In this work,we propose a method to generate high quality-factor extended electromagnetic fields via hybridizing the superradiant state and the quasi bound state in the continuum of graphene metasurfaces.The coupling interaction involved operates as a three-level system with multiple sharp resonances immune to the polarization,which holds great promise for developing nanodevices with high sensing capacity in two dimensions.展开更多
In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path cur...In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path current.The fabricated 1S1R exhibits stable direct current(DC)endurance(>200 cycles),suitable memory window(>40),matched selectivity(>40)and high uniformity of switching parameters.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11834011 and 12074245)the support from the Energy Materials and Surface Sciences Unit of the Okinawa Institute of Science and Technology Graduate University。
文摘Perovskite solar cells(PSCs)emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world.Both the efficiency and stability of PSCs have increased steadily in recent years,and the research on reducing lead leakage and developing eco-friendly lead-free perovskites pushes forward the commercialization of PSCs step by step.This review summarizes the main progress of PSCs in 2020 and 2021 from the aspects of efficiency,stability,perovskite-based tandem devices,and lead-free PSCs.Moreover,a brief discussion on the development of PSC modules and its challenges toward practical application is provided.
基金supported by the National Natural Science Foundation of China under Grant(No.62174093)the Natural Science Foundation of Ningbo under Grant(No.202003N4097)+5 种基金the support from the Beijing Institute of Technology Research Fund Program for Young Scholarsthe support from Guangdong Provincial Medical Science and Technology Research(A2019434)the support from Guangdong Provincial Key Laboratory of Computational Science and Material Design(2019B030301001)Fundamental Research Program of Shenzhen(JCYJ20190809174203802)National Natural Science Foundation of Guangdong Province(2022A1515110628)supported by Center for Computational Science and Engineering at Southern University of Science and Technology
文摘Nitrogen-doped three-dimensional graphene(N-doped 3D-graphene)is a graphene derivative with excellent adsorption capacity,large specific surface area,high porosity,and optoelectronic properties.Herein,N-doped 3D-graphene/Si heterojunctions were grown in situ directly on silicon(Si)substrates via plasma-assisted chemical vapor deposition(PACVD),which is promising for surface-enhanced Raman scattering(SERS)substrates candidates.Combined analyses of theoretical simulation,incorporating N atoms in 3D-graphene are beneficial to increase the electronic state density of the system and enhance the charge transfer between the substrate and the target molecules.The enhancement of the optical and electric fields benefits from the stronger light-matter interaction improved by the natural nano-resonator structure of N-doped 3D-graphene.The as-prepared SERS substrates based on N-doped 3D-graphene/Si heterojunctions achieve ultra-low detection for various molecules:10^(-8)M for methylene blue(MB)and 10^(-9)M for crystal violet(CRV)with rhodamine(R6G)of 10^(10)M.In practical detected,10^(-8)M thiram was precisely detected in apple peel extract.The results indicate that N-doped 3D-graphene/Si heterojunctions based-SERS substrates have promising applications in low-concentration molecular detection and food safety.
基金the National Natural Science Foundation of China(No.51802116)the Natural Science Foundation of Shandong Province for the Natural Science Fund for Excellent Young Scholars of Shandong Province(No.ZR202112010179)+9 种基金the Doctoral Fund(No.ZR2019BEM040)H.L.acknowledges the“20 Items of University”Project of Jinan(No.2018GXRC031)W.Z.thanks the Major Scientific and Technological Innovation Project of Shandong Province(No.2021CXGC010603)the National Natural Science Foundation of China(No.52022037)Taishan Scholars Project Special Funds(No.TSQN201812083)supported by the Foundation(No.GZKF202107)of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology,Shandong Academy of Sciencesthe National Natural Science Foundation of China(No.22003074)the National Natural Science Foundation of China(No.52071225)the National Science Center and the Czech Republic under the European Regional Development Fund(ERDF)program“Institute of Environmental Technology-Excellent Research”(No.CZ.02.1.01/0.0/0.0/16_019/0000853)the Sino-German Research Institute for support(No.GZ 1400).
文摘Human beings perceive the world through the senses of sight,hearing,smell,taste,touch,space,and balance.The first five senses are prerequisites for people to live.The sensing organs upload information to the nervous systems,including the brain,for interpreting the surrounding environment.Then,the brain sends commands to muscles reflexively to react to stimuli,including light,gas,chemicals,sound,and pressure.MXene,as an emerging two-dimensional material,has been intensively adopted in the applications of various sensors and actuators.In this review,we update the sensors to mimic five primary senses and actuators for stimulating muscles,which employ MXene-based film,membrane,and composite with other functional materials.First,a brief introduction is delivered for the structure,properties,and synthesis methods of MXenes.Then,we feed the readers the recent reports on the MXene-derived image sensors as artificial retinas,gas sensors,chemical biosensors,acoustic devices,and tactile sensors for electronic skin.Besides,the actuators of MXene-based composite are introduced.Eventually,future opportunities are given to MXene research based on the requirements of artificial intelligence and humanoid robot,which may induce prospects in accompanying healthcare and biomedical engineering applications.
基金financially supported by the National Key R&D Program of China(No.2021YFB3501401)the National Natural Science Foundation of China(Nos.52001103,U22A20117)Zhejiang Provincial Natural Science Foundation of China(No.LQ21E010001)。
文摘Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of the selection of materials and the response to external fields is essential for attaining desired functionality of a GMM.Herein,machine learning(ML)models are conducted to predict saturation magnetostrictions(λ_(s))in RFe_(2)-type(R=rare earth)GMMs with different compositions.According to ML-predicted composition–λsrelations,it is discovered that the values ofλshigher than1100×10^(-6)are almost situated in the composition space surrounded by 0.26≤x≤0.60 and 1.90≤y≤2.00 for the ternary compounds of Tb_(x)Dy_(1-x)Fe_(y).Assisted by ML predictions,the compositions are further narrowed down to the space surrounded by 0.26≤x≤0.32 and 1.92≤y≤1.97 for the excellent piezomagnetic(PM)performance in the Tb_(x)Dy_(1-x)Fe_(y)based PM device through our developed high-throughput(HTP)micromagnetic simulation(MMS)algorithm.Accordingly,high sensitivities up to10.22-13.61 m T·MPa^(-1)are observed in the optimized range within which the available experimental data fall well.This work not only provides valuable insights toward understanding the mechanism of magnetoelastic couplings,but also paves the way for designing and optimizing highperformance magnetostrictive materials and PM sensing devices.
基金This work was financially supported by the National Natural Science Foundation of China （Nos. 61306098, 61674050 and 61422407）, the Natural Science Foundation of Hebei Province （Nos. E2012201088 and E2013201176）, the Science Research Program of University in Hebei Province （No. ZH2012019）, Top-notch Youth Project of University in Hebei Province （No. BJ2014008）, the project of enhancement comprehensive strength of the Midwest universities of Hebei University, the Outstanding Youth Project of Hebei Province （No. F2016201220）, the outstanding Youth Cultivation Project of Hebei University （No. 2015JQY01）, Project of science and technology activities for overseas researcher （No. CL201602）, Post-graduate＇s Innovation Fund Project of Hebei University （No. X201714）, and Baoding Nanyang Research Institute - New Material Technology Platform （17H03）.
文摘Flexible memristor devices based on plastic substrates have attracted considerable attention due to their applications in wearable computers and integrated circuits. However, most plastic-substrate memristors cannot function or be grown in high-temperature environments. In this study, scotch-tape-exfoliated mica was used as the flexible memristor substrate in order to resolve these high-temperature issues. Our TiN/ZHO/IGZO memristor, which was constructed using a thin （10 μm） mica substrate, has superior flexibility and thermostability. After bending it 103 times, the device continues to exhibit exceptional electrical characteristics. It can also be implemented for transitions between high and low resistance states, even in temperatures of up to 300 ℃. More importantly, the biological synaptic characteristics of paired-pulse facilitation/depression （PPF/PPD） and spike- timing-dependent plasticity （STDP） were observed through applying different pulse measurement modes. This work demonstrates that flexible memristor devices on mica substrates may potentially allow for the realization of high-temperature memristor applications for biologically-inspired computing systems.
基金support from the National Science Fund for Distinguished Young Scholars(No.52225507)the National Key Research and Development Program of China(No.2021YFF0700402)the Fundamental Research Funds for the Central Universities.
文摘Photodetectors(PDs)play a crucial role in imaging,sensing,communication systems,etc.Graphene(Gr),a leading two-dimensional material,has demonstrated significant potential for photodetection in recent years.However,its relatively weak interaction with light poses challenges for practical applications.The integration of silicon(Si)and perovskite quantum dots(PQDs)has opened new avenues for Gr in the realm of next-generation optoelectronics.This review provides a comprehensive investigation of Gr/Si Schottky junction PDs and Gr/PQD hybrid PDs as well as their heterostructures.The operating principles,design,fabrication,optimization strategies,and typical applications of these devices are studied and summarized.Through these discussions,we aim to illuminate the current challenges and offer insights into future directions in this rapidly evolving field.
基金supported by the National Natural Science Foundation of China(Nos.61521064,61522408,61574169,6 1334007,61474136,61574166)the Ministry of Science andTechnology of China(Nos.2016YFA0201803,2016YFA0203800,2017YFB0405603)+2 种基金the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(Nos.QYZDB-SSWJSC048,QYZDY-SSW-JSC001)the Beijing Municipal Science and Technology Project(No.Z171100002017011)the Opening Project of the Key Laboratory of Microelectronic Devices&Integration Technology,Institute of Microelectronics of Chinese Academy of Sciences
文摘As a promising ultra-wide bandgap semiconductor, gallium oxide(Ga_2O_3) has attracted increasing attention in recent years. The high theoretical breakdown electrical field(8 MV/cm), ultra-wide bandgap(～ 4.8 eV) and large Baliga's figure of merit(BFOM) of Ga_2O_3 make it a potential candidate material for next generation high-power electronics, including diode and field effect transistor(FET). In this paper, we introduce the basic physical properties of Ga_2O_3 single crystal, and review the recent research process of Ga_2O_3 based field effect transistors. Furthermore, various structures of FETs have been summarized and compared, and the potential of Ga_2O_3 is preliminary revealed. Finally, the prospect of the Ga_2O_3 based FET for power electronics application is analyzed.
基金supported by the National Natural Science Foundation of China(No.51972310)the Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy of Sciences(CAS)+1 种基金the Youth Innovation Promotion Association,CAS(No.2011152)the Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)(No.U1501501).
文摘Noble nanometals are of significance in both scientific interest and technological applications,which are usually obtained by conventional wet-chemical synthesis.Organic surfactants are always used in the synthesis to prevent unexpected overgrowth and aggregation of noble nanometals.However,the surfactants are hard to remove and may interfere with plasmonic and catalytic studies,remaining surfactant-free synthesis of noble nanometals a challenge.Herein,we report an approach to epitaxial growth of sizecontrolled noble nanometals on MXenes.As piloted by density functional theory calculations,along with work function experimental determination,kinetic and spectroscopic studies,epitaxial growth of noble nanometals is initiated via a mechanism that involves an in situ redox reaction.In the redox,MXenes as two-dimensional solid reductants whose work functions are compatible with the reduction potentials of noble metal cations,enable spontaneous donation of electrons from the MXenes to noble metal cations and reduce the cations into nanoscale metallic metals on the outmost surface of MXenes.Neither surfactants nor external reductants are used during the whole synthesis process,which addresses a long-standing interference issue of surfactant and external reductant in the conventional wet-chemical synthesis.Moreover,the MXenes induced noble nanometals are size-controlled.Impressively,noble nanometals firmly anchored on MXenes exhibit excellent performance towards surface enhanced Raman scattering.Our developed strategy will promote the nanostructure-controlled synthesis of noble nanometals,offering new opportunities to further improve advanced functional properties towards practical applications.
基金financially supported by the National Natural Science Foundation of China (No.U22A20117)the National Natural Science Foundation of China (No.52271175)。
文摘The barocaloric effect(BCE)is a promising alternative to traditional vapor compressing refrigeration because of its environmentally friendly impact and high energy efficiency.However,the driving hydrostatic pressure for most BCE materials is relatively high,which is not conducive to practical application.In this paper,we report that the large barocaloric entropy change of MnAs_(0.94)Sb_(0.06)alloy can be induced by low hydrostatic pressures.Its phase transition temperature is strongly sensitive to the applied pressure,resulting in a large barocaloric coefficient of 134 K·GPa^(-1)on cooling and 126 K·GPa^(-1)on heating.The maximum barocaloric entropy change and adiabatic temperaturechange resulted from hydrostatic pressure of 40 MPa reach up to 26.3 J·kg^(-1)·K^(-1)and 14.4 K,respectively,showing an excellent barocaloric performance.The results demonstrate that the MnAs_(0.94)Sb_(0.06)alloy is a promising alternative for BCE refrigeration.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDA0330000 and Grant No.XDB44000000。
文摘Epilepsy is a common neurological disorder that occurs at all ages.Epilepsy not only brings physical pain to patients,but also brings a huge burden to the lives of patients and their families.At present,epilepsy detection is still achieved through the observation of electroencephalography(EEG)by medical staff.However,this process takes a long time and consumes energy,which will create a huge workload to medical staff.Therefore,it is particularly important to realize the automatic detection of epilepsy.This paper introduces,in detail,the overall framework of EEG-based automatic epilepsy identification and the typical methods involved in each step.Aiming at the core modules,that is,signal acquisition analog front end(AFE),feature extraction and classifier selection,method summary and theoretical explanation are carried out.Finally,the future research directions in the field of automatic detection of epilepsy are prospected.
基金supported by the National Natural Science Foundation of China(62171172).
文摘CMOS image sensors produced by the existing CMOS manufacturing process usually have difficulty achieving complete charge transfer owing to the introduction of potential barriers or Si/SiO_(2)interface state traps in the charge transfer path,which reduces the charge transfer efficiency and image quality.Until now,scholars have only considered mechanisms that limit charge transfer from the perspectives of potential barriers and spill back effect under high illumination condition.However,the existing models have thus far ignored the charge transfer limitation due to Si/SiO_(2)interface state traps in the transfer gate channel,particularly under low illumination.Therefore,this paper proposes,for the first time,an analytical model for quantifying the incomplete charge transfer caused by Si/SiO_(2)interface state traps in the transfer gate channel under low illumination.This model can predict the variation rules of the number of untransferred charges and charge transfer efficiency when the trap energy level follows Gaussian distribution,exponential distribution and measured distribution.The model was verified with technology computer-aided design simulations,and the results showed that the simulation results exhibit the consistency with the proposed model.
基金the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20210593)the Foundation of Jiangsu Provincial Double Innovation Doctor Program (Grant No. 30644)+2 种基金the National Natural Science Foundation of China (Grant No. 62204127)State Key Laboratory of Luminescence and Applications (Grant No. SKLA 202104)open research fund of Key Lab of Broadband Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications, Ministry of Education)。
文摘Dynamically tunable laser sources are highly promising for realizing visionary concepts of integrated photonic circuits and other applications. In this paper, a Ga N-based laser with an integrated PN junction heater on Si is fabricated.The photoluminescence properties of the Ga N beam cavity are controlled by temperature, and the Joule heater provides electrically driven regulation of temperature. These two features of the cavity make it possible to realize convenient tuning of the lasing properties. The multi-functional Ga N beam cavity achieves optically pumped lasing with a single mode near 362.4 nm with a high Q-factor of 1394. The temperature of this device increases by 0–5℃ under the Joule heating effect. Then, electrical control of the lasing mode is demonstrated. The lasing resonant peak shows a continuous redshift of about 0.5 nm and the device also exhibits dynamic switching of its lasing mode. The lasing modulation can be ascribed to temperature-induced reduction of the bandgap. Our work may be of benefit for external optical modulation in future chip-based optoelectronic devices.
基金support provided by the National Natural Science Foundation of China under Grant(No.62174093)Guangdong Provincial Key Laboratory of Computational Science and Material Design(2019B030301001)+1 种基金Fundamental Research Program of Shenzhen(JCYJ20190809174203802)K.C.Wong Magna Fund in Ningbo University and Natural Science Foundation of Ningbo under Grant(No.202003 N4097).
文摘Highly sensitive and uniform three-dimensional(3D)hybrid heterogeneous structures for use in surface-enhanced Raman scattering(SERS)experiments were fabricated by sequentially decorating high-quality,ultra-clean,graphene quantum dots(GQDs)and Ag nanoparticles(Ag-NPs)onto 3D-graphene.Finite-difference time-domain calculations and scanning Kelvin probe microscopy were used to verify that the Ag-NPs/GQDs/3D-graphene system facilitates substantial electromagnetic enhancement(due to the occurrence of two kinds of"gaps"between the Ag-NPs that form 3D"hot spots")and additional chemical enhancement(in detecting someπ-conjugated molecules).The SERS mechanism was explored in further detail via experimental analysis and confirmed by performing theoretical calculations.The large surface area of the 3D substrate(due to the large specific surface areas of the GQDs and 3D-graphene)results in a better enrichment effect which helps produce lower detection limits.In particular,the detection limits obtained using the Ag-NPs/GQDs/3D-graphene platform can reach 10^(-11)M for rhodamine 6G,10^(-10)M for methylene blue and dopamine,and 10^(-7)M for tetramethylthiuram disulfide and methyl parathion in apple juice(these are superior to most of the results reported using graphene-based SERS substrates).In summary,the 3D-platform Ag-NPs/GQDs/3D-graphene/Si shows outstanding SERS performance.It therefore has excellent application prospects in biochemical molecular detection and food safety monitoring.
基金supported by the National Natural Science Foundation of China(62101380)Tianjin Key Laboratory of Imaging and Sensing Microelectronic Technology。
文摘An integration of single-layer proximitycoupling patch antenna and solar cells with bandwidth enhancement and optical energy harvesting is proposed for sustainable communication.For this purpose,many dual-function components are selected for designing the miniaturized solar cell antenna.On the one hand,by greatly affecting the current flow of the rectangular patch,vias and proximity-coupling are introduced to control the resonance modes frequency and matching,respectively,for wideband application,and the radiation performance property can be achieved by high-order mode.On the other hand,vias and proximity-coupling are beneficial to complete direct-current(DC)loop of solar cell and improve compatibility of DC-RF(radio frequency),whereas a high-order mode is beneficial to increase the area of collected light energy.To prove the working principle,fabricated and manufactured solar cell antenna.The measured and simulated results illustrate that the solar cell antenna gain is raised to as high as 9.27 d Bi in4.37 to 5.06 GHz applied to fifth generation communication(5G).
文摘Since the first demonstrations of radio-frequency(RF)circuits,the physics of the electromagnetic(EM)field and its regulation and control with codesigned circuits,have become essential competencies of RF circuit designers.Leveraging advanced regulation or control methods,numerous high-performance circuits have been developed at RF and millimeter-wave(mm-wave)frequencies.Three main methods of electromagnetic regulation have been widely utilized,namely,the separation of electric and magnetic coupling paths,the manipulation of electromagnetic energy through the coupling of multiple tanks or multiple resonators,and the regulation of electromagnetic fields in air cavities or meta-substrates.The separated coupling paths of electric and magnetic fields provide guidance for designing a high-performance filter topology with a quasielliptical response through additional zeros.The manipulation of the EM field through electrical and magnetic intercouplings of multitanks or multiresonators,such as are used in oscillators,power amplifiers(PAs),etc.,results in remarkable power efficiency,size reduction,and wide bandwidth.The regulation of electromagnetism through an air cavity,patterned substrate,or metasubstrate reduces dielectric losses and size,especially when using a substrate integrated suspended line(SISL)platform.Many excellent circuits have been reported based on SISL with low loss,high integration,and self-packaging.Here,we present state-of-the-art cases that demonstrate the benefits of EM field regulation and control.
基金supported by the National Natural Science Foundation of China(52073131,51902148,and 12047501)the Fundamental Research Funds for the Central Universities(lzujbky-2021-it31,lzujbky-2021-59,lzujbky-2021-ct15,lzujbky2021-ct01,and lzujbky-2021-sp69)supported by Supercomputing Center of Lanzhou University。
文摘Two-dimensional(2D)Dion-Jacobson(D-J)-type cesium lead iodide CsPbI_(3) perform remarkably in terms of stability.However,the complex interactions between spacer and inorganic layers limit its excellent progress in perovskite solar cells(PSCs).Herein,starting from the considerable structural diversity of organic spacers,we engineer 2D CsPbI_(3) with fine-tuning functionalities.Specifically,for the first time we embedded fluorinated aromatic cations in 2D D-J CsPbI_(3),and successfully applied it into construction of high-performance PSCs.Compared with constitutive 1,4-diaminobenzene(PDA),the fluorinated 2-fluorobenzene-1,4-diamine(F-PDA)component greatly expands the dipole moment from 0.59 D to 3.47 D,which reduces the exciton binding energy of the system.A theoretical study shows that the spacer layer and inorganic plane are more enriched with charge accumulation in(F-PDA)Csn±1 Pb_(n)I_(3n+1).The results show that(F-PDA)Csn±1Pb_(n)I_(3n+1) demonstrates more significant charge transfer between organic and inorganic layers than(PDA)Csn±1 Pb_(n)I_(3n+1),and it is confirmed in the femtosecond transient absorption experiment.Moreover,the interactions of the fluorinated spacer with the[PbI_(6)]_(4)-plane effectively manipulate the crystallization quality,and thus the ion migration and defect formation of target 2D CsPbI_(3) are inhibited.As a result,we obtained a record power conversion efficiency(PCE)beyond 15%for 2D D-J(F-PDA)Cs_(3)Pb_(4)I_(13)(n=4)PSCs with significantly improved environmental stability compared with the three-dimensional(3D)counterparts.
基金the National Basic Research Program of China(Grant No.2013CBA01604)the National Science and Technology Major Project of China(Grant No.2011ZX02707)
文摘Poly(methyl methacrylate)(PMMA) is widely used for graphene transfer and device fabrication.However,it inevitably leaves a thin layer of polymer residues after acetone rinsing and leads to dramatic degradation of device performance.How to eliminate contamination and restore clean surfaces of graphene is still highly demanded.In this paper,we present a reliable and position-controllable method to remove the polymer residues on graphene films by laser exposure.Under proper laser conditions,PMMA residues can be substantially reduced without introducing defects to the underlying graphene.Furthermore,by applying this laser cleaning technique to the channel and contacts of graphene fieldeffect transistors(GFETs),higher carrier mobility as well as lower contact resistance can be realized.This work opens a way for probing intrinsic properties of contaminant-free graphene and fabricating high-performance GFETs with both clean channel and intimate graphene/metal contact.
基金This work was supported in part by the the National Natural Science Foundation of China(Nos.61974049,61922083,61804167,61834009,61904200,61821091,and 92064003)in part by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB44000000).
文摘Hafnia-based ferroelectrics have greatly revived the field of ferroelectric memory(FeRAM),but certain reliability issues must be satisfactorily resolved before they can be widely applied in commercial memories.In particular,the imprint phenomenon severely jeopardizes the read-out reliability in hafnia-based ferroelectric capacitors,but its origin remains unclear,which hinders the development of its recovery schemes.In this work,we have systematically investigated the imprint mechanism in TiN/Hf_(0.5)Zr_(0.5)O_(2)(HZO)/TiN ferroelectric capacitors using experiments and first-principles calculations.It is shown that carrier injection-induced charged oxygen vacancies are at the heart of imprint in HZO,where other mechanisms such as domain pinning and dead layer are less important.An imprint model based on electron de-trapping from oxygen vacancy sites has been proposed that can satisfactorily explain several experimental facts such as the strong asymmetric imprint,leakage current variation,and so forth.Based on this model,an effective imprint recovery method has been proposed,which utilizes unipolar rather than bipolar voltage inputs.The remarkable recovery performances demonstrate the prospect of improved device reliability in hafnia-based FeRAM devices.
基金This work was partially supported by the National Natural Science Foundation of China(Nos.12104339,62174118,1210040201,U20A20164,and 61975177)Open Fund of State Key Laboratory of Millimeter Wave,Southeast University(No.K202216)+1 种基金International Postdoctoral Exchange Fellowship Program(Talent-Introduction)China Postdoctoral Science Foundation(Nos.258023 and 2021M702403).
文摘Plasmonics could provide compact and powerful solutions for manipulating light in deep-subwavelength dimensions,which is promising for a great range of nanophotonic technologies such as plasmonic rulers and sensors.However,the effective area of enhanced localized field induced by surface plasmon polaritons is typically restricted to the structural boundaries.In this work,we propose a method to generate high quality-factor extended electromagnetic fields via hybridizing the superradiant state and the quasi bound state in the continuum of graphene metasurfaces.The coupling interaction involved operates as a three-level system with multiple sharp resonances immune to the polarization,which holds great promise for developing nanodevices with high sensing capacity in two dimensions.
基金financially supported by the National Natural Science Foundation of China(No.61904050)the Science and Technology Major Project of Hubei(Nos.2020AAA005 and 2020AEA017)+1 种基金the Scientific Research Project of Education Department of Hubei Province(No.Q20181009)Hubei Key Laboratory of Advanced Memories。
文摘In this letter,the Ti-doped NbO_(x)-based selector is applied to SiNOx-based resistive random-access memory(RRAM),forming Pt/NbOx(Ti-doped)/SiNO_(x)/Ti one selector-one RRAM device(1S1R),to suppress the sneak path current.The fabricated 1S1R exhibits stable direct current(DC)endurance(>200 cycles),suitable memory window(>40),matched selectivity(>40)and high uniformity of switching parameters.
