Ice accretion on aircraft encountering supercooled water droplets in clouds poses great risks to flight performance and safety.With the aim of optimizing the newly developed streamwise plasma heat knife method for ant...Ice accretion on aircraft encountering supercooled water droplets in clouds poses great risks to flight performance and safety.With the aim of optimizing the newly developed streamwise plasma heat knife method for anti-icing,a parametric investigation is carried out in this work.The influence of the detailed voltage profile on the heating effects of a Surface Dielectric Barrier Discharge driven by Nanosecond Pulses(NS-SDBD)is investigated,and a comparison of the antiicing performance among different configurations of streamwise plasma heat knife is made.The results show that columnar high-temperature regions produced by a multi-streamer discharge appear at small pulse rise time,but become diffuse as the pulse rise time increases.An optimal pulse rise time exists to provide a wide range and high value of temperature,which is found to be 150 ns for the setup in the present study.The influence of the pulse fall time is much weaker than that of the rise time.The range and value of the temperature decrease with increasing pulse fall time.A greater pulse width is found to improve the heating effect by increasing the discharge power.When a spanwise electrode is placed connecting the streamwise electrodes of the streamwise plasma heat knife at the airfoil leading edge,the anti-icing performance becomes poorer,whereas good performance is achieved when the spanwise electrode is at the edge of the streamwise electrodes.Based on this,a three-level configuration of the plasma heat knife is proposed,and its anti-icing performance is found to be much better than that of the original configuration.展开更多
A vertical junction barrier Schottky diode with a high-K/low-K compound dielectric structure is proposed and optimized to achieve a high breakdown voltage(BV).There is a discontinuity of the electric field at the inte...A vertical junction barrier Schottky diode with a high-K/low-K compound dielectric structure is proposed and optimized to achieve a high breakdown voltage(BV).There is a discontinuity of the electric field at the interface of high-K and low-K layers due to the different dielectric constants of high-K and low-K dielectric layers.A new electric field peak is introduced in the n-type drift region of junction barrier Schottky diode(JBS),so the distribution of electric field in JBS becomes more uniform.At the same time,the effect of electric-power line concentration at the p-n junction interface is suppressed due to the effects of the high-K dielectric layer and an enhancement of breakdown voltage can be achieved.Numerical simulations demonstrate that GaN JBS with a specific on-resistance(R_(on,sp)) of 2.07 mΩ·cm^(2) and a BV of 4171 V which is 167% higher than the breakdown voltage of the common structure,resulting in a high figure-of-merit(FOM) of 8.6 GW/cm^(2),and a low turn-on voltage of 0.6 V.展开更多
Lateralβ-Ga_(2)O_(3)Schottky barrier diodes(SBDs)each are fabricated on an unintentionally doped(-201)n-typeβ-Ga_(2)O_(3)single crystal substrate by designing L-shaped electrodes.By introducing sidewall electrodes o...Lateralβ-Ga_(2)O_(3)Schottky barrier diodes(SBDs)each are fabricated on an unintentionally doped(-201)n-typeβ-Ga_(2)O_(3)single crystal substrate by designing L-shaped electrodes.By introducing sidewall electrodes on both sides of the conductive channel,the SBD demonstrates a high current density of 223 mA/mm and low specific on-resistance of4.7 mΩ·cm^(2).Temperature-dependent performance is studied and the Schottky barrier height is extracted to be in a range between 1.3 eV and 1.35 eV at temperatures ranging from 20℃to 150℃.These results suggest that the lateralβ-Ga_(2)O_(3)SBD has a tremendous potential for future power electronic applications.展开更多
The space charge effect (SCE) of static induction transistor (SIT) that occurs in high current region is systematically studied.The I V equations are deduced and well agree with experimental results.Two kinds of ...The space charge effect (SCE) of static induction transistor (SIT) that occurs in high current region is systematically studied.The I V equations are deduced and well agree with experimental results.Two kinds of barriers are presented in SIT,corresponding to channel voltage barrier control (CVBC) mechanism and space charge limited control (SCLC) mechanism respectively.With the increase of drain voltage,the gradual transferring of operational mechanism from CVBC to SCLC is demonstrated.It points out that CVBC mechanism and its contest relationship with space charge barrier makes the SIT distinctly differentiated from JFET and triode devices,etc.The contest relationship of the two potential barriers also results in three different working regions,which are distinctly marked and analyzed.Furthermore,the extreme importance of grid voltage on SCE is illustrated.展开更多
An enhancement-mode （E-mode） A1GaN/GaN high electron mobility transistor （HEMTs） was fabricated with 15-nm A1GaN barrier layer. E-mode operation was achieved by using fluorine plasma treatment and post-gate rapid ...An enhancement-mode （E-mode） A1GaN/GaN high electron mobility transistor （HEMTs） was fabricated with 15-nm A1GaN barrier layer. E-mode operation was achieved by using fluorine plasma treatment and post-gate rapid thermal annealing. The thin barrier depletion-HEMTs with a threshold voltage typically around -1.7 V, which is higher than that of the 22-nm barrier depletion-mode HEMTs （-3.5 V）. Therefore, the thin barrier is emerging as an excellent candidate to realize the enhancement-mode operation. With 0.6-tim gate length, the devices treated by fluorine plasma for 150-W RF power at 150 s exhibited a threshold voltage of 1.3 V. The maximum drain current and maximum transconductance are 300 mA/mm, and 177 mS/ram, respectively. Compared with the 22-nm barrier E-mode devices, VT of the thin barrier HEMTs is much more stable under the gate step-stress,展开更多
Voltage dependence of resistivity(VDR)is a widely existing phenomenon insemiconducting ceramics, but there is no quantitative study on this phenomenon. Inthis note, the quantitative results of voltage dependence of re...Voltage dependence of resistivity(VDR)is a widely existing phenomenon insemiconducting ceramics, but there is no quantitative study on this phenomenon. Inthis note, the quantitative results of voltage dependence of resistivity insemiconducting ceramics are obtained from the grain boundary barrier model, andthe methods to decrease the voltage dependence of resistivity in sendconductingceramics are proposed.展开更多
The influence of actuating voltage and discharge gap on plasma assisted detonation initiation by alternating current dielectric barrier discharge was studied in detail.A loose coupling method was used to simulate the ...The influence of actuating voltage and discharge gap on plasma assisted detonation initiation by alternating current dielectric barrier discharge was studied in detail.A loose coupling method was used to simulate the detonation initiation process of a hydrogen–oxygen mixture in a detonation tube under different actuating voltage amplitudes and discharge gap sizes.Both the discharge products and the detonation forming process assisted by the plasma were analyzed.It was found that the patterns of the temporal and spatial distributions of discharge products in one cycle keep unchanged as changing the two discharge operating parameters.However,the adoption of a higher actuating voltage leads to a higher active species concentration within the discharge zone,and atom H is the most sensitive to the variations of the actuating voltage amplitude among the given species.Adopting a larger discharge gap results in a lower concentration of the active species,and all species have the same sensitivity to the variations of the gap.With respect to the reaction flow of the detonation tube,the corresponding deflagration to detonation transition（DDT） time and distance become slightly longer when a higher actuating voltage is chosen.The acceleration effect of plasma is more prominent with a smaller discharge gap,and the benefit builds gradually throughout the DDT process.Generally,these two control parameters have little effect on the amplitude of the flow field parameters,and they do not alter the combustion degree within the reaction zone.展开更多
Based on current voltage（I-Vg） and capacitance voltage（C-Vg） measurements,a reliable procedure is proposed to determine the effective surface potential Vd（Vg） in Schottky diodes.In the framework of thermionic em...Based on current voltage（I-Vg） and capacitance voltage（C-Vg） measurements,a reliable procedure is proposed to determine the effective surface potential Vd（Vg） in Schottky diodes.In the framework of thermionic emission,our analysis includes both the effect of the series resistance and the ideality factor,even voltage dependent. This technique is applied to n-type indium phosphide（n-InP） Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C-Vg measurements.The study clearly shows that the depletion width and the flat band barrier height deduced from C-Vg,which are important parameters directly related to the surface potential in the semiconductor,should be estimated within our approach to obtain more reliable information.展开更多
We investigate the influence of voltage drop across the lightly doped drain（LDD） region and the built-in potential on MOSFETs,and develop a threshold voltage model for high-k gate dielectric MOSFETs with fully overl...We investigate the influence of voltage drop across the lightly doped drain（LDD） region and the built-in potential on MOSFETs,and develop a threshold voltage model for high-k gate dielectric MOSFETs with fully overlapped LDD structures by solving the two-dimensional Poisson＇s equation in the silicon and gate dielectric layers.The model can predict the fringing-induced barrier lowering effect and the short channel effect.It is also valid for non-LDD MOSFETs.Based on this model,the relationship between threshold voltage roll-off and three parameters,channel length,drain voltage and gate dielectric permittivity,is investigated.Compared with the non-LDD MOSFET,the LDD MOSFET depends slightly on channel length,drain voltage,and gate dielectric permittivity.The model is verified at the end of the paper.展开更多
The multilevel storage capability of nonvolatile resistive random access memory(ReRAM)is greatly de-sired to accomplish high functioning memory density.In this study,Ta_(2)O_(5) thin film with different thick-nesses(2...The multilevel storage capability of nonvolatile resistive random access memory(ReRAM)is greatly de-sired to accomplish high functioning memory density.In this study,Ta_(2)O_(5) thin film with different thick-nesses(2,4,and 6 nm)was exploited as an appropriate interfacial barrier layer for limiting the formation of the interfacial layer between the 10 nm thick sputtering deposited resistive switching(RS)layer and Ta ohmic electrode to improve the switching cycle endurance and uniformity.Results show that lower form-ing voltage,narrow distribution of SET-voltages,good dc switching cycles(10^(3)),high pulse endurance(10^(6) cycles),long retention time(10^(4) s at room temperature and 100℃),and reliable multilevel resis-tance states were obtained at an appropriate thickness of∼2 nm Ta_(2)O_(5) interfacial barrier layer instead of without Ta_(2)O_(5) and with∼4 nm,and∼6 nm Ta_(2)O_(5) barrier layer,ZrO_(2)-based memristive devices.Besides,multilevel resistance states have been scientifically investigated via modulating the compliance current(CC)and RESET-stop voltages,which displays that all of the resistance states were distinct and stayed stable without any considerable deprivation over 10^(4) s retention time and 104 pulse endurance cycles.The I-V characteristics of RESET-stop voltage(from−1.7 to−2.3 V)of HRS are found to be a good linear fit with the Schottky equation.It can be seen that Schottky barrier height rises by increasing the stop-voltage during RESET-operation,resulting in enhancing the data storage memory window(on/offratio).Moreover,RESET-voltage and CC control of HRS and LRS revealed the physical origin of the RS mecha-nism,which entails the formation and rupture of conducting nanofilaments.It is thoroughly investigated that proper optimization of the barrier layer at the ohmic interface and the switching layer is essential in memristive devices.These results demonstrate that the ZrO_(2)-based memristive device with an optimized∼2 nm Ta_(2)O_(5) barrier layer is a promising candidate fo展开更多
In this paper,an asymmetric electrode geometry(the misalignment between the ends of highvoltage and grounded electrodes)is proposed in order to investigate the effects of the transverse electric field on nanosecond pu...In this paper,an asymmetric electrode geometry(the misalignment between the ends of highvoltage and grounded electrodes)is proposed in order to investigate the effects of the transverse electric field on nanosecond pulsed dielectric barrier discharge(DBD).The results show that diffuse discharge manifests in the misaligned region and the micro-discharge channel in the aligned region moves directionally.Moreover,the diffuse discharge area increases with the decrease of the discharge gap and pulse repetition frequency,which is consistent with the variation of the moving velocity of the micro-discharge channel.When airflow is introduced into the discharge gap in the same direction as the transverse electric field,the dense filamentary discharge region at the airflow inlet of asymmetric electrode geometry is larger than that of symmetric electrode geometry.However,when the direction of the airflow is opposite to that of the transverse electric field,the dense filamentary discharge region of asymmetric electrode geometry is reduced.The above phenomena are mainly attributed to the redistribution of the space charges induced by the transverse electric field.展开更多
基金co-supported by the National Natural Science Foundation of China(Nos.12002384 and 11802341)National Science and Technology Major Project of China(No.J2019-Ⅱ-0014-0035)+1 种基金National Key Laboratory Fund of China(No.614220220200109)the Academician Workstation Foundation of the Green Aerotechnics Research Institute of Chongqing Jiaotong University,China(No.GATRI2020C06003)。
文摘Ice accretion on aircraft encountering supercooled water droplets in clouds poses great risks to flight performance and safety.With the aim of optimizing the newly developed streamwise plasma heat knife method for anti-icing,a parametric investigation is carried out in this work.The influence of the detailed voltage profile on the heating effects of a Surface Dielectric Barrier Discharge driven by Nanosecond Pulses(NS-SDBD)is investigated,and a comparison of the antiicing performance among different configurations of streamwise plasma heat knife is made.The results show that columnar high-temperature regions produced by a multi-streamer discharge appear at small pulse rise time,but become diffuse as the pulse rise time increases.An optimal pulse rise time exists to provide a wide range and high value of temperature,which is found to be 150 ns for the setup in the present study.The influence of the pulse fall time is much weaker than that of the rise time.The range and value of the temperature decrease with increasing pulse fall time.A greater pulse width is found to improve the heating effect by increasing the discharge power.When a spanwise electrode is placed connecting the streamwise electrodes of the streamwise plasma heat knife at the airfoil leading edge,the anti-icing performance becomes poorer,whereas good performance is achieved when the spanwise electrode is at the edge of the streamwise electrodes.Based on this,a three-level configuration of the plasma heat knife is proposed,and its anti-icing performance is found to be much better than that of the original configuration.
基金Project supported by the National Natural Science Foundation of China (Grant No.61376078)the Natural Science Foundation of Sichuan Province,China (Grant No.2022NSFSC0515)。
文摘A vertical junction barrier Schottky diode with a high-K/low-K compound dielectric structure is proposed and optimized to achieve a high breakdown voltage(BV).There is a discontinuity of the electric field at the interface of high-K and low-K layers due to the different dielectric constants of high-K and low-K dielectric layers.A new electric field peak is introduced in the n-type drift region of junction barrier Schottky diode(JBS),so the distribution of electric field in JBS becomes more uniform.At the same time,the effect of electric-power line concentration at the p-n junction interface is suppressed due to the effects of the high-K dielectric layer and an enhancement of breakdown voltage can be achieved.Numerical simulations demonstrate that GaN JBS with a specific on-resistance(R_(on,sp)) of 2.07 mΩ·cm^(2) and a BV of 4171 V which is 167% higher than the breakdown voltage of the common structure,resulting in a high figure-of-merit(FOM) of 8.6 GW/cm^(2),and a low turn-on voltage of 0.6 V.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018 YFB 2200500)the National Natural Science Foundation of China(Grant Nos.62050073,62090054,and 61975196)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDY-SSW-JSC022)。
文摘Lateralβ-Ga_(2)O_(3)Schottky barrier diodes(SBDs)each are fabricated on an unintentionally doped(-201)n-typeβ-Ga_(2)O_(3)single crystal substrate by designing L-shaped electrodes.By introducing sidewall electrodes on both sides of the conductive channel,the SBD demonstrates a high current density of 223 mA/mm and low specific on-resistance of4.7 mΩ·cm^(2).Temperature-dependent performance is studied and the Schottky barrier height is extracted to be in a range between 1.3 eV and 1.35 eV at temperatures ranging from 20℃to 150℃.These results suggest that the lateralβ-Ga_(2)O_(3)SBD has a tremendous potential for future power electronic applications.
文摘The space charge effect (SCE) of static induction transistor (SIT) that occurs in high current region is systematically studied.The I V equations are deduced and well agree with experimental results.Two kinds of barriers are presented in SIT,corresponding to channel voltage barrier control (CVBC) mechanism and space charge limited control (SCLC) mechanism respectively.With the increase of drain voltage,the gradual transferring of operational mechanism from CVBC to SCLC is demonstrated.It points out that CVBC mechanism and its contest relationship with space charge barrier makes the SIT distinctly differentiated from JFET and triode devices,etc.The contest relationship of the two potential barriers also results in three different working regions,which are distinctly marked and analyzed.Furthermore,the extreme importance of grid voltage on SCE is illustrated.
基金supported by the Major Program and State Key Program of National Natural Science Foundation of China (GrantNos. 60890191 and 60736033)the National Key Science & Technology Special Project (Grant No. 2008ZX01002-002)
文摘An enhancement-mode （E-mode） A1GaN/GaN high electron mobility transistor （HEMTs） was fabricated with 15-nm A1GaN barrier layer. E-mode operation was achieved by using fluorine plasma treatment and post-gate rapid thermal annealing. The thin barrier depletion-HEMTs with a threshold voltage typically around -1.7 V, which is higher than that of the 22-nm barrier depletion-mode HEMTs （-3.5 V）. Therefore, the thin barrier is emerging as an excellent candidate to realize the enhancement-mode operation. With 0.6-tim gate length, the devices treated by fluorine plasma for 150-W RF power at 150 s exhibited a threshold voltage of 1.3 V. The maximum drain current and maximum transconductance are 300 mA/mm, and 177 mS/ram, respectively. Compared with the 22-nm barrier E-mode devices, VT of the thin barrier HEMTs is much more stable under the gate step-stress,
文摘Voltage dependence of resistivity(VDR)is a widely existing phenomenon insemiconducting ceramics, but there is no quantitative study on this phenomenon. Inthis note, the quantitative results of voltage dependence of resistivity insemiconducting ceramics are obtained from the grain boundary barrier model, andthe methods to decrease the voltage dependence of resistivity in sendconductingceramics are proposed.
基金supported by National Natural Science Foundation of China with grant numbers 91441123,51777214the Open Project of Science and Technology on Scramjet Laboratory with grant number CG-2014-05-118 under the technical monitor of program manager Dr Zhiyong Lin
文摘The influence of actuating voltage and discharge gap on plasma assisted detonation initiation by alternating current dielectric barrier discharge was studied in detail.A loose coupling method was used to simulate the detonation initiation process of a hydrogen–oxygen mixture in a detonation tube under different actuating voltage amplitudes and discharge gap sizes.Both the discharge products and the detonation forming process assisted by the plasma were analyzed.It was found that the patterns of the temporal and spatial distributions of discharge products in one cycle keep unchanged as changing the two discharge operating parameters.However,the adoption of a higher actuating voltage leads to a higher active species concentration within the discharge zone,and atom H is the most sensitive to the variations of the actuating voltage amplitude among the given species.Adopting a larger discharge gap results in a lower concentration of the active species,and all species have the same sensitivity to the variations of the gap.With respect to the reaction flow of the detonation tube,the corresponding deflagration to detonation transition（DDT） time and distance become slightly longer when a higher actuating voltage is chosen.The acceleration effect of plasma is more prominent with a smaller discharge gap,and the benefit builds gradually throughout the DDT process.Generally,these two control parameters have little effect on the amplitude of the flow field parameters,and they do not alter the combustion degree within the reaction zone.
文摘Based on current voltage（I-Vg） and capacitance voltage（C-Vg） measurements,a reliable procedure is proposed to determine the effective surface potential Vd（Vg） in Schottky diodes.In the framework of thermionic emission,our analysis includes both the effect of the series resistance and the ideality factor,even voltage dependent. This technique is applied to n-type indium phosphide（n-InP） Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C-Vg measurements.The study clearly shows that the depletion width and the flat band barrier height deduced from C-Vg,which are important parameters directly related to the surface potential in the semiconductor,should be estimated within our approach to obtain more reliable information.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60936005 and 61076097)the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China(Grant No.708083)the Fundamental Research Funds for the Central Universities of China(Grant No.20110203110012)
文摘We investigate the influence of voltage drop across the lightly doped drain（LDD） region and the built-in potential on MOSFETs,and develop a threshold voltage model for high-k gate dielectric MOSFETs with fully overlapped LDD structures by solving the two-dimensional Poisson＇s equation in the silicon and gate dielectric layers.The model can predict the fringing-induced barrier lowering effect and the short channel effect.It is also valid for non-LDD MOSFETs.Based on this model,the relationship between threshold voltage roll-off and three parameters,channel length,drain voltage and gate dielectric permittivity,is investigated.Compared with the non-LDD MOSFET,the LDD MOSFET depends slightly on channel length,drain voltage,and gate dielectric permittivity.The model is verified at the end of the paper.
基金supported in part by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIP) (No.2021R1C1C1004422)the Dongguk University Research Fund of 2020supported through the National Research Foundation of Korea (NRF) funded by the Ministry of Science,ICT & Future Planning (Nos.NRF2020M3F3A2A02082449 and NRF-2016R1A6A1A03013422)。
文摘The multilevel storage capability of nonvolatile resistive random access memory(ReRAM)is greatly de-sired to accomplish high functioning memory density.In this study,Ta_(2)O_(5) thin film with different thick-nesses(2,4,and 6 nm)was exploited as an appropriate interfacial barrier layer for limiting the formation of the interfacial layer between the 10 nm thick sputtering deposited resistive switching(RS)layer and Ta ohmic electrode to improve the switching cycle endurance and uniformity.Results show that lower form-ing voltage,narrow distribution of SET-voltages,good dc switching cycles(10^(3)),high pulse endurance(10^(6) cycles),long retention time(10^(4) s at room temperature and 100℃),and reliable multilevel resis-tance states were obtained at an appropriate thickness of∼2 nm Ta_(2)O_(5) interfacial barrier layer instead of without Ta_(2)O_(5) and with∼4 nm,and∼6 nm Ta_(2)O_(5) barrier layer,ZrO_(2)-based memristive devices.Besides,multilevel resistance states have been scientifically investigated via modulating the compliance current(CC)and RESET-stop voltages,which displays that all of the resistance states were distinct and stayed stable without any considerable deprivation over 10^(4) s retention time and 104 pulse endurance cycles.The I-V characteristics of RESET-stop voltage(from−1.7 to−2.3 V)of HRS are found to be a good linear fit with the Schottky equation.It can be seen that Schottky barrier height rises by increasing the stop-voltage during RESET-operation,resulting in enhancing the data storage memory window(on/offratio).Moreover,RESET-voltage and CC control of HRS and LRS revealed the physical origin of the RS mecha-nism,which entails the formation and rupture of conducting nanofilaments.It is thoroughly investigated that proper optimization of the barrier layer at the ohmic interface and the switching layer is essential in memristive devices.These results demonstrate that the ZrO_(2)-based memristive device with an optimized∼2 nm Ta_(2)O_(5) barrier layer is a promising candidate fo
基金supported by National Natural Science Foundation of China(No.51437002)。
文摘In this paper,an asymmetric electrode geometry(the misalignment between the ends of highvoltage and grounded electrodes)is proposed in order to investigate the effects of the transverse electric field on nanosecond pulsed dielectric barrier discharge(DBD).The results show that diffuse discharge manifests in the misaligned region and the micro-discharge channel in the aligned region moves directionally.Moreover,the diffuse discharge area increases with the decrease of the discharge gap and pulse repetition frequency,which is consistent with the variation of the moving velocity of the micro-discharge channel.When airflow is introduced into the discharge gap in the same direction as the transverse electric field,the dense filamentary discharge region at the airflow inlet of asymmetric electrode geometry is larger than that of symmetric electrode geometry.However,when the direction of the airflow is opposite to that of the transverse electric field,the dense filamentary discharge region of asymmetric electrode geometry is reduced.The above phenomena are mainly attributed to the redistribution of the space charges induced by the transverse electric field.
