Rectifying circuit,as a crucial component for converting alternating current into direct current,plays a pivotal role in energy harvesting microsystems.Traditional silicon-based or germanium-based rectifier diodes hin...Rectifying circuit,as a crucial component for converting alternating current into direct current,plays a pivotal role in energy harvesting microsystems.Traditional silicon-based or germanium-based rectifier diodes hinder system integration due to their specific manufacturing processes.Conversely,metal oxide diodes,with their simple fabrication techniques,offer advantages for system integration.The oxygen vacancy defect of oxide semiconductor will greatly affect the electrical performance of the device,so the performance of the diode can be effectively controlled by adjusting the oxygen vacancy concentration.This study centers on optimizing the performance of diodes by modulating the oxygen vacancy concentration within InGaZnO films through control of oxygen flows during the sputtering process.Experimental results demonstrate that the diode exhibits a forward current density of 43.82 A·cm^(−2),with a rectification ratio of 6.94×10^(4),efficiently rectifying input sine signals with 1 kHz frequency and 5 V magnitude.These results demonstrate its potential in energy conversion and management.By adjusting the oxygen vacancy,a methodology is provided for optimizing the performance of rectifying diodes.展开更多
There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW...There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW absorbers,still pose challenges,especially in elucidating the correlation between composition,morphology,interface,and performance.Here,we construct 3D hierarchical porous conducting network structures and Schottky heterojunctions(MoNi_(4)@NC-NiFe_(2)O_(4)@NC)with a high density of defects,using trimetallic NiMoFe-MOFs.Synergistic enhancement of the dielectric and magnetic losses is realized through manipulation of the defects,interfaces,phase engineering,and magnetic resonance.In particular,the even dispersion of magnetic MoNi_(4) and NiFe_(2)O_(4)nanoparticles(NPs)within the carbon matrix triggers the creation of multiple heterogeneous interfaces.These inseparable interfaces,along with oxygen vacancies,play a role in enhancing dielectric polarization,while the closely spaced interactions among magnetic units contribute to magnetic loss.After optimizing the interfacial structure,NiFe_(2)O_(4)/MoNi_(4)-NC exhibits remarkable EMW absorption properties.A reflection loss(RL)value of-67.91 dB can be achieved at an ultra-thin thickness of 1.95 mm,and the effective absorption bandwidth(EAB,RL≤-10 dB)is as high as 5.76 GHz.Furthermore,we conducted radar scattering cross-section(RCS)simulations using computer simulation technology(CST)software,which revealed that NiFe_(2)O_(4)/MoNi_(4)-NC exhibits an RCS reduction value of 39.1 dB m^(2).Hence,this work provides comprehensive guidance for the construction of Schottky heterojunctions for lightweight EMW absorbers from a mechanistic point of view.展开更多
Schottky mass spectrometry utilizing heavy-ion storage rings is a powerful technique for the precise mass and decay half-life measurements of highly charged ions.Owing to the nondestructive ion detection features of S...Schottky mass spectrometry utilizing heavy-ion storage rings is a powerful technique for the precise mass and decay half-life measurements of highly charged ions.Owing to the nondestructive ion detection features of Schottky noise detectors,the number of stored ions in the ring is determined by the peak area in the measured revolution frequency spectrum.Because of their intrinsic amplitude-frequency characteristic(AFC),Schottky detector systems exhibit varying sensitivities at different frequencies.Using low-energy electron-cooled stored ions,a new method is developed to calibrate the AFC curve of the Schottky detector system of the Experimental Cooler Storage Ring(CSRe)storage ring located in Lanzhou,China.Using the amplitude-calibrated frequency spectrum,a notable refinement was observed in the precision of both the peak position and peak area.As a result,the storage lifetimes of the electron-cooled fully ionized^(56)Fe^(26+)ions were determined with high precision at beam energies of 13.7 and 116.4 MeV/u,despite of frequency drifts during the experiment.When electron cooling was turned off,the effective vacuum condition experienced by the 116.4 MeV/u^(56)Fe^(26+)ions was determined using amplitude-calibrated spectra,revealing a value of 2×10^(−10)mbar,which is consistent with vacuum gauge readings along the CSRe ring.The method reported herein will be adapted for the next-generation storage ring of the HIAF facility under construction in Huizhou,China.It can also be adapted to other storage ring facilities worldwide to improve precision and enhance lifetime measurements using many ions in the ring.展开更多
Schottky contacts have attracted widespread attention from both the electronic device industry and researchers since their discovery.The Schottky characteristics make these contacts highly suitable for use in field-ef...Schottky contacts have attracted widespread attention from both the electronic device industry and researchers since their discovery.The Schottky characteristics make these contacts highly suitable for use in field-effect transistors(FETs),photodetectors(PDs),solar cells(SCs),resistive-switching memories(RSMs),thin-film transistors(TFTs),etc.However,how do Schottky contacts affect the device performance?The answer lies simply in the Schottky parameters.This review focuses on the extraction of Schottky parameters,i.e.,the Schottky barrier height(SBH),ideality factor(IF),and series resistance(SR),from the current-voltage(I−V)curve to understand and analyze the characteristics of Schottky devices.First,the current research progress in this field and the principles of Schottky contacts are presented.Second,this article delves into some classic and widely used extraction methods as well as the latest extraction methods,providing an objective evaluation based on their practical effectiveness.Then,several research applications,including studies that require extraction,simple extraction,and delicate extraction,are enumerated to demonstrate the necessity and importance of Schottky parameter analysis.Finally,an outlook and future research prospects are discussed based on recent progress,and a comprehensive summary is given.展开更多
Nitrate pollution poses a significant environmental challenge,and photocatalytic nitrate reduction has garnered considerable attention due to its efficiency and environmental advantages.Among these,the development of ...Nitrate pollution poses a significant environmental challenge,and photocatalytic nitrate reduction has garnered considerable attention due to its efficiency and environmental advantages.Among these,the development of Schottky junctions shows considerable potential for practical applications.However,the impact of metal nanoparticle size within Schottky junctions on photocatalytic nitrate reduction remains largely unexplored.In this study,we propose a novel method to modulate metal nanoparticle size within Schottky junctions by controlling light intensity during the photodeposition process.Smaller Au nanoparticles were found to enhance electron accumulation at active sites by promoting charge transfer from COF to Au,thereby improving internal electron transport.Additionally,the Schottky barrier effectively suppressed reverse electron transfer while enhancing NO_(3)^(–)adsorption and activation.The Au_(2-)COF exhibited remarkable nitrate reduction performance,achieving an ammonia yield of 382.48μmol g^(–1)h^(–1),5.7 times higher than that of pure COF.This work provides novel theoretical and practical insights into using controlled light intensity to regulate metal nanoparticle size within Schottky junctions,thereby enhancing photocatalytic nitrate reduction.展开更多
Plasmon-induced hot electron can transfer from noble metal to its cohesive semiconductor in their heterostructure to initiate the photocatalytic reaction upon resonance excitation.However,the co-excitation of semicond...Plasmon-induced hot electron can transfer from noble metal to its cohesive semiconductor in their heterostructure to initiate the photocatalytic reaction upon resonance excitation.However,the co-excitation of semiconductor in the heterostructure would also lead to the inversus transfer of photo-electron from semiconductor to noble metal,which inevitably limits the use of active electrons.After co-excitation of both localized surface plasmon resonance(LSPR)of noble metal and interband transition of semiconductor,the interfacial electron transfer process strongly depends on the energy band configuration of their heterostructure.When the Au content in the AuAg alloy nanoparticles(NPs)changes from 0 to 100 at.%,the interfacial energy band configuration at AuAg NPs/TiO_(2) NPs in the electrospun nanofibers(NFs)shifts from Ohmic to Schottky contacts.Further investigation finds that the optimal Schottky barrier configuration in Au_(0.25)Ag_(0.75)/TiO_(2) NFs can not only boost the plasmon-induced hot electron transfer from Au_(0.25)Ag_(0.75) to TiO_(2) NPs,but also suppresses the backflow of photo-electrons from TiO_(2) to Au_(0.25)Ag_(0.75) NPs in NFs.Thus,upon UV-visible light irradiation,the CO_(2) photo-reduction activity of Au_(0.25)Ag_(0.75)/TiO_(2) NFs is~3 and~2 times higher than that of either Ag/TiO_(2) or Au/TiO_(2) NFs.展开更多
The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual compon...The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual component and their phase-dependent unique properties.Using the plasma-enhanced chemical vapor deposition(PECVD)method,we analyze the fabrication of heterostructures consisting of two phases of molybdenum disulfide(MoS_(2))in four different cases.The initial hydrogen evolution reaction(HER)polarization curve indicates that the activity of the heterostructure MoS_(2)is consistent with that of the underlying MoS_(2),rather than the surface activity of the upper MoS_(2).This behavior can be attributed to the presence of Schottky barriers,which include contact resistance,which significantly hampers the efficient charge transfer at junctions between the two different phases of MoS_(2)layers and is mediated by van der Waals bonds.Remarkably,the energy barrier at the junction dissipates upon reaching a certain electrochemical potential,indicating surface activation from the top phase of MoS_(2)in the heterostructure.Notably,the 1T/2H MoS_(2)heterostructure demonstrates enhanced electrochemical stability compared to its metastable 1T-MoS_(2).This fundamental understanding paves the way for the creation of phase-controllable heterostructures through an experimentally viable PECVD,offering significant promise for a wide range of applications.展开更多
A compact drain current including the variation of barrier heights and carrier quantization in ultrathin-body and double-gate Schottky barrier MOSFETs （UTBDG SBFETs） is developed. In this model, Schrodinger＇s equat...A compact drain current including the variation of barrier heights and carrier quantization in ultrathin-body and double-gate Schottky barrier MOSFETs （UTBDG SBFETs） is developed. In this model, Schrodinger＇s equation is solved using the triangular potential well approximation. The carrier density thus obtained is included in the space charge density to obtain quantum carrier confinement effects in the modeling of thin-body devices. Due to the quantum effects, the first subband is higher than the conduction band edge, which is equivalent to the band gap widening. Thus, the barrier heights at the source and drain increase and the carrier concentration decreases as the drain current decreases. The drawback of the existing models,which cannot present an accurate prediction of the drain current because they mainly consider the effects of Schottky barrier lowering （SBL） due to image forces,is eliminated. Our research results suggest that for small nonnegative Schottky barrier （SB） heights,even for zero barrier height, the tunneling current also plays a role in the total on-state currents. Verification of the present model was carried out by the device numerical simulator-Silvaco and showed good agreement.展开更多
This paper describes the fabrication and electrical characteristics of Ti/4H-SiC Schottky barrier diodes （SBDs）. The ideality factor n = 1.08 and effective Schottky barrier heightφ= 1.05eV of the SBDs were measured...This paper describes the fabrication and electrical characteristics of Ti/4H-SiC Schottky barrier diodes （SBDs）. The ideality factor n = 1.08 and effective Schottky barrier heightφ= 1.05eV of the SBDs were measured with the method of forward current density-voltage （J-V）. A low reverse leakage current below 5.96 ×10^-3A/cm^2 at a bias voltage of - 1. 1kV was obtained. By using B^＋ implantation,an amorphous layer as the edge termination was formed. We used the PECVD SiO2 as the field plate dielectric. The SBDs have an on-state current density of 430A/cm^2 at a forward voltage drop of about 4V. The specific on-resistance Ro, was found to be 6. 77mΩ2 · cm^2 .展开更多
Design and fabrication of Schottky barrier diodes (SBD) with a commercial standard 0 35μm CMOS process are described.In order to reduce the series resistor of Schottky contact,interdigitating the fingers of schottky...Design and fabrication of Schottky barrier diodes (SBD) with a commercial standard 0 35μm CMOS process are described.In order to reduce the series resistor of Schottky contact,interdigitating the fingers of schottky diode layout is adopted.The I-V,C-V ,and S parameter are measured.The parameters of realized SBD such as the saturation current,breakdown voltage,and the Schottky barrier height are given.The SPICE simulation model of the realized SBDs is given.展开更多
The excellent reverse breakdown characteristics of Schottky barrier varactor(SBV)are crucially required for the application of high power and high efficiency multipliers.The SBV with a novel Schottky structure named m...The excellent reverse breakdown characteristics of Schottky barrier varactor(SBV)are crucially required for the application of high power and high efficiency multipliers.The SBV with a novel Schottky structure named metal-brim is fabricated and systemically evaluated.Compared with normal structure,the reverse breakdown voltage of the new type SBV improves from-7.31 V to-8.75 V.The simulation of the Schottky metal-brim SBV is also proposed.Three factors,namely distribution of leakage current,the electric field,and the area of space charge region are mostly concerned to explain the physical mechanism.Schottky metal-brim structure is a promising approach to improve the reverse breakdown voltage and reduce leakage current by eliminating the accumulation of charge at Schottky electrode edge.展开更多
Polycrystalline and epitaxial CoSi 2 films are formed on the n-Si (111) substrates by solid state reaction of the as-deposited Co single-layer and Co/Ti bilayer with Si,respectively at different annealing phase.The C...Polycrystalline and epitaxial CoSi 2 films are formed on the n-Si (111) substrates by solid state reaction of the as-deposited Co single-layer and Co/Ti bilayer with Si,respectively at different annealing phase.The CoSi 2/Si Schottky contacts are measured with the current-voltage and capacitance-voltage (I-V/C-V) techniques within the range of temperature from 90K to room temperature.The measured I-V characteristics have been analyzed with a model based on the inhomogeneity in Schottky barrier height,i.e.,at high temperatures (≥～200K) or low temperatures but with a large bias,the I-V curves can be described by using the thermionic emission theory with a Gaussian distributed barrier height over the whole junction,while at low temperatures and with a small bias,the current is dominated by some small patches with low barrier height.It results in a plateau-like section in the low temperature I-V curves around 10 -7 A.At room temperature,the barrier height of polycrystalline CoSi 2/Si deduced from the I-V curve is about 0 57eV.For epitaxial CoSi 2,the barrier height depends on its final annealing temperature and increases from 0 54eV to 0 60eV with the annealing temperature increasing from 700℃ to 900℃.展开更多
We investigate the effects of the surface states on the Schottky contacts in 4H-SiC MESFET. The Ti/Pt/Au gate metal contacts are deposited by electron beam evaporation and patterned by a lift-off process. Based on the...We investigate the effects of the surface states on the Schottky contacts in 4H-SiC MESFET. The Ti/Pt/Au gate metal contacts are deposited by electron beam evaporation and patterned by a lift-off process. Based on thermionic theory,a simple parameter extraction method is developed for determination of the surface states in metal/4H-SiC Schottky contacts. The interface state density and interface capacitance are calculated to be 4. 386 × 10^12 cm^-2 · eV^- 1 and 6. 394 × 10^-6 F/cm^2 ,which are consistent with the device＇s terminal characteristics.展开更多
文摘Rectifying circuit,as a crucial component for converting alternating current into direct current,plays a pivotal role in energy harvesting microsystems.Traditional silicon-based or germanium-based rectifier diodes hinder system integration due to their specific manufacturing processes.Conversely,metal oxide diodes,with their simple fabrication techniques,offer advantages for system integration.The oxygen vacancy defect of oxide semiconductor will greatly affect the electrical performance of the device,so the performance of the diode can be effectively controlled by adjusting the oxygen vacancy concentration.This study centers on optimizing the performance of diodes by modulating the oxygen vacancy concentration within InGaZnO films through control of oxygen flows during the sputtering process.Experimental results demonstrate that the diode exhibits a forward current density of 43.82 A·cm^(−2),with a rectification ratio of 6.94×10^(4),efficiently rectifying input sine signals with 1 kHz frequency and 5 V magnitude.These results demonstrate its potential in energy conversion and management.By adjusting the oxygen vacancy,a methodology is provided for optimizing the performance of rectifying diodes.
基金supported by the National Natural Science Foundation of China(No.22269010)the Jiangxi Provincial Natural Science Foundation(No.20224BAB214021).
文摘There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW absorbers,still pose challenges,especially in elucidating the correlation between composition,morphology,interface,and performance.Here,we construct 3D hierarchical porous conducting network structures and Schottky heterojunctions(MoNi_(4)@NC-NiFe_(2)O_(4)@NC)with a high density of defects,using trimetallic NiMoFe-MOFs.Synergistic enhancement of the dielectric and magnetic losses is realized through manipulation of the defects,interfaces,phase engineering,and magnetic resonance.In particular,the even dispersion of magnetic MoNi_(4) and NiFe_(2)O_(4)nanoparticles(NPs)within the carbon matrix triggers the creation of multiple heterogeneous interfaces.These inseparable interfaces,along with oxygen vacancies,play a role in enhancing dielectric polarization,while the closely spaced interactions among magnetic units contribute to magnetic loss.After optimizing the interfacial structure,NiFe_(2)O_(4)/MoNi_(4)-NC exhibits remarkable EMW absorption properties.A reflection loss(RL)value of-67.91 dB can be achieved at an ultra-thin thickness of 1.95 mm,and the effective absorption bandwidth(EAB,RL≤-10 dB)is as high as 5.76 GHz.Furthermore,we conducted radar scattering cross-section(RCS)simulations using computer simulation technology(CST)software,which revealed that NiFe_(2)O_(4)/MoNi_(4)-NC exhibits an RCS reduction value of 39.1 dB m^(2).Hence,this work provides comprehensive guidance for the construction of Schottky heterojunctions for lightweight EMW absorbers from a mechanistic point of view.
基金supported by the National Key R&D Program of China (No. 2023YFA1606401 and 2018YFA0404401)the Young Scholar of Regional Development,CAS ([2023] 15)+1 种基金Chinese Academy of Sciences Stable Support for Young Teams in Basic Research (No. YSBR-002)Special Fund for Strategic Pilot Technology of Chinese Academy of Sciences (No. XDB34000000)
文摘Schottky mass spectrometry utilizing heavy-ion storage rings is a powerful technique for the precise mass and decay half-life measurements of highly charged ions.Owing to the nondestructive ion detection features of Schottky noise detectors,the number of stored ions in the ring is determined by the peak area in the measured revolution frequency spectrum.Because of their intrinsic amplitude-frequency characteristic(AFC),Schottky detector systems exhibit varying sensitivities at different frequencies.Using low-energy electron-cooled stored ions,a new method is developed to calibrate the AFC curve of the Schottky detector system of the Experimental Cooler Storage Ring(CSRe)storage ring located in Lanzhou,China.Using the amplitude-calibrated frequency spectrum,a notable refinement was observed in the precision of both the peak position and peak area.As a result,the storage lifetimes of the electron-cooled fully ionized^(56)Fe^(26+)ions were determined with high precision at beam energies of 13.7 and 116.4 MeV/u,despite of frequency drifts during the experiment.When electron cooling was turned off,the effective vacuum condition experienced by the 116.4 MeV/u^(56)Fe^(26+)ions was determined using amplitude-calibrated spectra,revealing a value of 2×10^(−10)mbar,which is consistent with vacuum gauge readings along the CSRe ring.The method reported herein will be adapted for the next-generation storage ring of the HIAF facility under construction in Huizhou,China.It can also be adapted to other storage ring facilities worldwide to improve precision and enhance lifetime measurements using many ions in the ring.
基金financially supported by Guangxi Science and Technology Plan Project(Nos.AD21220150,2023GXNSFBA026216,AD21220056,and 2023JJG170001)the National Natural Sci-ence Foundation of China(Nos.51802032,52262022,52061009,62174041,and 62361022)the Yunnan Province Major Science and Technology Projects(No.202102AB080008-2).
文摘Schottky contacts have attracted widespread attention from both the electronic device industry and researchers since their discovery.The Schottky characteristics make these contacts highly suitable for use in field-effect transistors(FETs),photodetectors(PDs),solar cells(SCs),resistive-switching memories(RSMs),thin-film transistors(TFTs),etc.However,how do Schottky contacts affect the device performance?The answer lies simply in the Schottky parameters.This review focuses on the extraction of Schottky parameters,i.e.,the Schottky barrier height(SBH),ideality factor(IF),and series resistance(SR),from the current-voltage(I−V)curve to understand and analyze the characteristics of Schottky devices.First,the current research progress in this field and the principles of Schottky contacts are presented.Second,this article delves into some classic and widely used extraction methods as well as the latest extraction methods,providing an objective evaluation based on their practical effectiveness.Then,several research applications,including studies that require extraction,simple extraction,and delicate extraction,are enumerated to demonstrate the necessity and importance of Schottky parameter analysis.Finally,an outlook and future research prospects are discussed based on recent progress,and a comprehensive summary is given.
文摘Nitrate pollution poses a significant environmental challenge,and photocatalytic nitrate reduction has garnered considerable attention due to its efficiency and environmental advantages.Among these,the development of Schottky junctions shows considerable potential for practical applications.However,the impact of metal nanoparticle size within Schottky junctions on photocatalytic nitrate reduction remains largely unexplored.In this study,we propose a novel method to modulate metal nanoparticle size within Schottky junctions by controlling light intensity during the photodeposition process.Smaller Au nanoparticles were found to enhance electron accumulation at active sites by promoting charge transfer from COF to Au,thereby improving internal electron transport.Additionally,the Schottky barrier effectively suppressed reverse electron transfer while enhancing NO_(3)^(–)adsorption and activation.The Au_(2-)COF exhibited remarkable nitrate reduction performance,achieving an ammonia yield of 382.48μmol g^(–1)h^(–1),5.7 times higher than that of pure COF.This work provides novel theoretical and practical insights into using controlled light intensity to regulate metal nanoparticle size within Schottky junctions,thereby enhancing photocatalytic nitrate reduction.
基金supported by the National Natural Science Foundation of China(Nos.:22472021,U23A20102,12074055,22402021 and 62005036)Liaoning Revitalization Talents Program(XLYC2202036,XLYC1807176)+4 种基金Natural Science Foundation of Liaoning Province for Excellent Young Scholars(2022-YQ-13)Fundamental Research Funds for the Central Universities(044420250072)Dalian Science Foundation for Distinguished Young Scholars(2018RJ05)Natural Science Foundation of Liaoning Province(2023-MS-132)Joint Funds of the Science and Technology Program of Liaoning Province(No.2024JH2/102600101).
文摘Plasmon-induced hot electron can transfer from noble metal to its cohesive semiconductor in their heterostructure to initiate the photocatalytic reaction upon resonance excitation.However,the co-excitation of semiconductor in the heterostructure would also lead to the inversus transfer of photo-electron from semiconductor to noble metal,which inevitably limits the use of active electrons.After co-excitation of both localized surface plasmon resonance(LSPR)of noble metal and interband transition of semiconductor,the interfacial electron transfer process strongly depends on the energy band configuration of their heterostructure.When the Au content in the AuAg alloy nanoparticles(NPs)changes from 0 to 100 at.%,the interfacial energy band configuration at AuAg NPs/TiO_(2) NPs in the electrospun nanofibers(NFs)shifts from Ohmic to Schottky contacts.Further investigation finds that the optimal Schottky barrier configuration in Au_(0.25)Ag_(0.75)/TiO_(2) NFs can not only boost the plasmon-induced hot electron transfer from Au_(0.25)Ag_(0.75) to TiO_(2) NPs,but also suppresses the backflow of photo-electrons from TiO_(2) to Au_(0.25)Ag_(0.75) NPs in NFs.Thus,upon UV-visible light irradiation,the CO_(2) photo-reduction activity of Au_(0.25)Ag_(0.75)/TiO_(2) NFs is~3 and~2 times higher than that of either Ag/TiO_(2) or Au/TiO_(2) NFs.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),funded by the Ministry of Education(2022R1A3B1078163 and 2022R1A4A1031182)supported by the KIMM institutional program(NK248E)and NST/KIMM+3 种基金supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(20024772),(RS-2023-00264860)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)(1415187508)supported by the US Department of Energy,Office of Science,Office of Basic Energy Sciences,under grant no.DE-FG02-87ER13808by Northwestern University.
文摘The exploration of heterostructures composed of two-dimensional(2D)transition metal dichalcogenide(TMDc)materials has garnered significant research attention due to the distinctive properties of each individual component and their phase-dependent unique properties.Using the plasma-enhanced chemical vapor deposition(PECVD)method,we analyze the fabrication of heterostructures consisting of two phases of molybdenum disulfide(MoS_(2))in four different cases.The initial hydrogen evolution reaction(HER)polarization curve indicates that the activity of the heterostructure MoS_(2)is consistent with that of the underlying MoS_(2),rather than the surface activity of the upper MoS_(2).This behavior can be attributed to the presence of Schottky barriers,which include contact resistance,which significantly hampers the efficient charge transfer at junctions between the two different phases of MoS_(2)layers and is mediated by van der Waals bonds.Remarkably,the energy barrier at the junction dissipates upon reaching a certain electrochemical potential,indicating surface activation from the top phase of MoS_(2)in the heterostructure.Notably,the 1T/2H MoS_(2)heterostructure demonstrates enhanced electrochemical stability compared to its metastable 1T-MoS_(2).This fundamental understanding paves the way for the creation of phase-controllable heterostructures through an experimentally viable PECVD,offering significant promise for a wide range of applications.
文摘A compact drain current including the variation of barrier heights and carrier quantization in ultrathin-body and double-gate Schottky barrier MOSFETs （UTBDG SBFETs） is developed. In this model, Schrodinger＇s equation is solved using the triangular potential well approximation. The carrier density thus obtained is included in the space charge density to obtain quantum carrier confinement effects in the modeling of thin-body devices. Due to the quantum effects, the first subband is higher than the conduction band edge, which is equivalent to the band gap widening. Thus, the barrier heights at the source and drain increase and the carrier concentration decreases as the drain current decreases. The drawback of the existing models,which cannot present an accurate prediction of the drain current because they mainly consider the effects of Schottky barrier lowering （SBL） due to image forces,is eliminated. Our research results suggest that for small nonnegative Schottky barrier （SB） heights,even for zero barrier height, the tunneling current also plays a role in the total on-state currents. Verification of the present model was carried out by the device numerical simulator-Silvaco and showed good agreement.
文摘This paper describes the fabrication and electrical characteristics of Ti/4H-SiC Schottky barrier diodes （SBDs）. The ideality factor n = 1.08 and effective Schottky barrier heightφ= 1.05eV of the SBDs were measured with the method of forward current density-voltage （J-V）. A low reverse leakage current below 5.96 ×10^-3A/cm^2 at a bias voltage of - 1. 1kV was obtained. By using B^＋ implantation,an amorphous layer as the edge termination was formed. We used the PECVD SiO2 as the field plate dielectric. The SBDs have an on-state current density of 430A/cm^2 at a forward voltage drop of about 4V. The specific on-resistance Ro, was found to be 6. 77mΩ2 · cm^2 .
文摘Design and fabrication of Schottky barrier diodes (SBD) with a commercial standard 0 35μm CMOS process are described.In order to reduce the series resistor of Schottky contact,interdigitating the fingers of schottky diode layout is adopted.The I-V,C-V ,and S parameter are measured.The parameters of realized SBD such as the saturation current,breakdown voltage,and the Schottky barrier height are given.The SPICE simulation model of the realized SBDs is given.
文摘The excellent reverse breakdown characteristics of Schottky barrier varactor(SBV)are crucially required for the application of high power and high efficiency multipliers.The SBV with a novel Schottky structure named metal-brim is fabricated and systemically evaluated.Compared with normal structure,the reverse breakdown voltage of the new type SBV improves from-7.31 V to-8.75 V.The simulation of the Schottky metal-brim SBV is also proposed.Three factors,namely distribution of leakage current,the electric field,and the area of space charge region are mostly concerned to explain the physical mechanism.Schottky metal-brim structure is a promising approach to improve the reverse breakdown voltage and reduce leakage current by eliminating the accumulation of charge at Schottky electrode edge.
文摘Polycrystalline and epitaxial CoSi 2 films are formed on the n-Si (111) substrates by solid state reaction of the as-deposited Co single-layer and Co/Ti bilayer with Si,respectively at different annealing phase.The CoSi 2/Si Schottky contacts are measured with the current-voltage and capacitance-voltage (I-V/C-V) techniques within the range of temperature from 90K to room temperature.The measured I-V characteristics have been analyzed with a model based on the inhomogeneity in Schottky barrier height,i.e.,at high temperatures (≥～200K) or low temperatures but with a large bias,the I-V curves can be described by using the thermionic emission theory with a Gaussian distributed barrier height over the whole junction,while at low temperatures and with a small bias,the current is dominated by some small patches with low barrier height.It results in a plateau-like section in the low temperature I-V curves around 10 -7 A.At room temperature,the barrier height of polycrystalline CoSi 2/Si deduced from the I-V curve is about 0 57eV.For epitaxial CoSi 2,the barrier height depends on its final annealing temperature and increases from 0 54eV to 0 60eV with the annealing temperature increasing from 700℃ to 900℃.
文摘We investigate the effects of the surface states on the Schottky contacts in 4H-SiC MESFET. The Ti/Pt/Au gate metal contacts are deposited by electron beam evaporation and patterned by a lift-off process. Based on thermionic theory,a simple parameter extraction method is developed for determination of the surface states in metal/4H-SiC Schottky contacts. The interface state density and interface capacitance are calculated to be 4. 386 × 10^12 cm^-2 · eV^- 1 and 6. 394 × 10^-6 F/cm^2 ,which are consistent with the device＇s terminal characteristics.
