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
The on-resistance degradations of the p-type lateral extended drain MOS transistor （pLEDMOS） with thick gate oxide under different hot carrier stress conditions are different, which has been experimentally investiga...The on-resistance degradations of the p-type lateral extended drain MOS transistor （pLEDMOS） with thick gate oxide under different hot carrier stress conditions are different, which has been experimentally investigated. This difference results from the interface trap generation and the hot electron injection, and trapping into the thick gate oxide and field oxide of the pLEDMOS transistor. An improved method to reduce the on-resistance degradations is also presented, which uses the field oxide as the gate oxide instead of the thick gate oxide. The effects are analyzed with a MEDICI simulator.展开更多
AIM： To clarify whether the incidence of post-endoscopic retrograde cholangiopancreatography （ERCP） pancreatitis （PEP） after pancreatic guidewire placement （PGW） can be reduced by using a different cannulation ...AIM： To clarify whether the incidence of post-endoscopic retrograde cholangiopancreatography （ERCP） pancreatitis （PEP） after pancreatic guidewire placement （PGW） can be reduced by using a different cannulation method. METHODS： BebNeen April 2001 and October 2009, PGW was performed in 142 patients with native papilla to overcome difficult biliary cannulation. Our cannulation method for ERCP was changed from contrast injection （CI） using a single-lumen catheter （April 2001-May 2008） to wire-guided cannulation （WGC） using a double-lumen catheter （June 2008-October 2009）. The CI protocol was also changed during the study period： in the first period it was used for routine pancreatography for detecting small pancreatic cancer （April 2001-November 2002）, whereas in the second period it was not （December 2002-May 2008）. In PGW with CI using a single- lumen catheter, the contrast medium in the catheter lumen was injected into the pancreatic duct. The success rate of biliary cannulation, the incidence of PEP according to the cannulation method, and the impact of CI using a single-lumen catheter on PEP in comparison with WGC using a double-lumen catheter were investigated.RESULTS： CI with routine pancreatography, CI without routine pancreatography, and WGC were performed in 27 patients, 77 patients and 38 patients, respectively. Routine pancreatography did not contribute to the early diagnosis of pancreatic cancer in our study period. In CI without routine pancreatography and WGC, diagnostic pancreatography was performed in 17 patients and no patients, respectively. The success rate of biliary cannulation by PGW alone was 69%, and the final success rate was increased to 80.3% by the addition of consecutive maneuvers or a second ERCP. PEP occurred in 22 patients （15.5%）, and the severity was mild in all cases. When analyzed according to cannulation method, the incidence of PEP was 37.0% （10/27） in the patients who underwent CI with routine pancreatography, 14.3% （11/77） in those who underwent CI without routine pancreatography, and 2.6% （1/38） in those who underwent WGC. In all patients who underwent CI using a singlelumen catheter, the incidence of PEP was 20% （21/104）, which was significantly higher than that in WGC using a double-lumen catheter. In univariate and multivariate analysis, CI using a single-lumen catheter showed a high, statistically significant, odds ratio for PEP after PGW. CONCLUSION： The practice of a cannulation method involving the use of a double-lumen catheter minimizes the CI dose administered to the pancreatic duct and reduces the incidence of PEP after PGW.展开更多
We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted ...We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted multiple stripe conventional single quantum well separate confinement heterostructure(SQW-SCH) GaAlAs diode laser array has been realized.These devices exhibit the lateral far-field radiation pattern of a phase-locked array of gain-guided semiconductor injection laser array.The twenty stripe laser array has a lateral far-field beam divergence full width at half maximum(FWHM) of less than 3°,and three twenty stripe laser array has a beam divergence in the plane of the junction of about 9°.展开更多
A novel crosslinkable water/alcohol soluble conjugated polymer PFN-C containing oxetane groups and aminoalkyl groups in the side chains has been developed and used as highly efficient electron injection and transporti...A novel crosslinkable water/alcohol soluble conjugated polymer PFN-C containing oxetane groups and aminoalkyl groups in the side chains has been developed and used as highly efficient electron injection and transporting material for polymer light-emitting diodes (PLEDs). The unique solubility in polar solvents and crosslinkable ability of PFN-C render it a good can- didate for solution processed multilayer PLEDs. It was found that PFN-C can greatly enhance the electron injection from high work-function metal cathode, due to its pendant amino groups. As a result, PLEDs with PFN-C/Al cathode exhibited compara- ble device performance to the devices with Ba/Al cathode. The resulting green light-emitting device showed promising perfor- mance with a maximum luminance efficiency of 13.53 cd A-1.展开更多
Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art perfo...Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art performance,the high photoluminescence quantum yield(PLQY)of the active emission layer,the balanced charge injection,and the optimized optical extraction should be considered simultaneously.Multiple chemical passivation strategies have been provided as controllable and efficient methods to improve the PLQY of the perovskite layer.However,high luminance under large injection current and high external quantum efficiency(EQE)can hardly be achieved due to Auger recombination at high carrier density.Here,we decreased the electron injection barrier by tuning the Fermi-level of the perovskite,leading to a reduced turn on voltage.Through molecular doping of the hole injection material,a more balanced hole injection was achieved.At last,a device with modified charge injection realizes high luminance and quantum efficiency simultaneously.The best device exhibits luminance of 55,000 cd m^-2 EQE of 8.02%at the working voltage of 2.65 V,current density of 115 mA cm^-2,and shows EQE T50 stability around 160 min at 100 mA cm^-2 injection current density.展开更多
A series of alkali metal salts doped pluronic block copolymer F127 were used as electron injection/transport layers (ETLs) for polymer light-emitting diodes with poly[2-(4-(3′,7′-dimethyloctyloxy)-phenyl)-p-phenylen...A series of alkali metal salts doped pluronic block copolymer F127 were used as electron injection/transport layers (ETLs) for polymer light-emitting diodes with poly[2-(4-(3′,7′-dimethyloctyloxy)-phenyl)-p-phenylenevinylene] (P-PPV) as the emission layer. It was found that the electron transport capability of F127 can be effectively enhanced by doping with alkali metal salts. By using Li2CO3 (15%) doped F127 as ETL, the resulting device exhibited improved performance with a maximum luminous efficiency (LE) of 13.59 cd/A and a maximum brightness of 5529 cd/m2, while the device with undoped F127 as ETL only showed a maximum LE of 8.78 cd/A and a maximum brightness of 2952 cd/m2. The effects of the doping concentration, cations and anions of the alkali metal salts on the performance of the resulting devices were investigated. It was found that most of the alkali metal salt dopants can dramatically enhance the electron transport capability of F127 ETL and the performance of the resulting devices was greatly improved.展开更多
Carbon-based spintronics refers mainly to the spin injection and transport in carbon materials including carbon nanotubes,graphene,fullerene,and organic materials.In the last decade,extraordinary development has been ...Carbon-based spintronics refers mainly to the spin injection and transport in carbon materials including carbon nanotubes,graphene,fullerene,and organic materials.In the last decade,extraordinary development has been achieved for carbon-based spintronics,and the spin transport has been studied in both local and nonlocal spin valve devices.A series of theoretical and experimental studies have been done to reveal the spin relaxation mechanisms and spin transport properties in carbon materials,mostly for graphene and carbon nanotubes.In this article,we provide a brief review on spin injection and transport in graphene,carbon nanotubes,fullerene and organic thin films.展开更多
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The on-resistance degradations of the p-type lateral extended drain MOS transistor （pLEDMOS） with thick gate oxide under different hot carrier stress conditions are different, which has been experimentally investigated. This difference results from the interface trap generation and the hot electron injection, and trapping into the thick gate oxide and field oxide of the pLEDMOS transistor. An improved method to reduce the on-resistance degradations is also presented, which uses the field oxide as the gate oxide instead of the thick gate oxide. The effects are analyzed with a MEDICI simulator.
文摘AIM： To clarify whether the incidence of post-endoscopic retrograde cholangiopancreatography （ERCP） pancreatitis （PEP） after pancreatic guidewire placement （PGW） can be reduced by using a different cannulation method. METHODS： BebNeen April 2001 and October 2009, PGW was performed in 142 patients with native papilla to overcome difficult biliary cannulation. Our cannulation method for ERCP was changed from contrast injection （CI） using a single-lumen catheter （April 2001-May 2008） to wire-guided cannulation （WGC） using a double-lumen catheter （June 2008-October 2009）. The CI protocol was also changed during the study period： in the first period it was used for routine pancreatography for detecting small pancreatic cancer （April 2001-November 2002）, whereas in the second period it was not （December 2002-May 2008）. In PGW with CI using a single- lumen catheter, the contrast medium in the catheter lumen was injected into the pancreatic duct. The success rate of biliary cannulation, the incidence of PEP according to the cannulation method, and the impact of CI using a single-lumen catheter on PEP in comparison with WGC using a double-lumen catheter were investigated.RESULTS： CI with routine pancreatography, CI without routine pancreatography, and WGC were performed in 27 patients, 77 patients and 38 patients, respectively. Routine pancreatography did not contribute to the early diagnosis of pancreatic cancer in our study period. In CI without routine pancreatography and WGC, diagnostic pancreatography was performed in 17 patients and no patients, respectively. The success rate of biliary cannulation by PGW alone was 69%, and the final success rate was increased to 80.3% by the addition of consecutive maneuvers or a second ERCP. PEP occurred in 22 patients （15.5%）, and the severity was mild in all cases. When analyzed according to cannulation method, the incidence of PEP was 37.0% （10/27） in the patients who underwent CI with routine pancreatography, 14.3% （11/77） in those who underwent CI without routine pancreatography, and 2.6% （1/38） in those who underwent WGC. In all patients who underwent CI using a singlelumen catheter, the incidence of PEP was 20% （21/104）, which was significantly higher than that in WGC using a double-lumen catheter. In univariate and multivariate analysis, CI using a single-lumen catheter showed a high, statistically significant, odds ratio for PEP after PGW. CONCLUSION： The practice of a cannulation method involving the use of a double-lumen catheter minimizes the CI dose administered to the pancreatic duct and reduces the incidence of PEP after PGW.
文摘We report one thick layer of hard-baked photoresist mask.The laser array stripe pattern was defined by standard wet lithography.With this mask, a 10 W QCW(quasi-continuous wave) operation of a narrow proton implanted multiple stripe conventional single quantum well separate confinement heterostructure(SQW-SCH) GaAlAs diode laser array has been realized.These devices exhibit the lateral far-field radiation pattern of a phase-locked array of gain-guided semiconductor injection laser array.The twenty stripe laser array has a lateral far-field beam divergence full width at half maximum(FWHM) of less than 3°,and three twenty stripe laser array has a beam divergence in the plane of the junction of about 9°.
基金financially supported by the Natural Science Foundation of China (50990065, 51010003, 51073058 & 20904011)the National Basic Research Program of China (973 Program, 2009CB623601)the Fun-damental Research Funds for the Central Universities, South China Uni-versity of Technology
文摘A novel crosslinkable water/alcohol soluble conjugated polymer PFN-C containing oxetane groups and aminoalkyl groups in the side chains has been developed and used as highly efficient electron injection and transporting material for polymer light-emitting diodes (PLEDs). The unique solubility in polar solvents and crosslinkable ability of PFN-C render it a good can- didate for solution processed multilayer PLEDs. It was found that PFN-C can greatly enhance the electron injection from high work-function metal cathode, due to its pendant amino groups. As a result, PLEDs with PFN-C/Al cathode exhibited compara- ble device performance to the devices with Ba/Al cathode. The resulting green light-emitting device showed promising perfor- mance with a maximum luminance efficiency of 13.53 cd A-1.
基金in part supported by Research Grants Council of Hong Kong,particularly,via Grant Nos.Ao E/P-03/08,T23-407/13-N,Ao E/P-02/12,14207515,14204616CUHK Group Research Scheme,and ITS/088/17 by Innovation and Technology Commission,Hong Kong SAR Governmentthe National Natural Science Foundation of China for the support,particularly,via Grant No.61229401。
文摘Metal halide perovskite light emitting diodes(PeLEDs)have recently experienced rapid development due to the tunable emission wavelengths,narrow emission linewidth and low material cost.To achieve stateof-the-art performance,the high photoluminescence quantum yield(PLQY)of the active emission layer,the balanced charge injection,and the optimized optical extraction should be considered simultaneously.Multiple chemical passivation strategies have been provided as controllable and efficient methods to improve the PLQY of the perovskite layer.However,high luminance under large injection current and high external quantum efficiency(EQE)can hardly be achieved due to Auger recombination at high carrier density.Here,we decreased the electron injection barrier by tuning the Fermi-level of the perovskite,leading to a reduced turn on voltage.Through molecular doping of the hole injection material,a more balanced hole injection was achieved.At last,a device with modified charge injection realizes high luminance and quantum efficiency simultaneously.The best device exhibits luminance of 55,000 cd m^-2 EQE of 8.02%at the working voltage of 2.65 V,current density of 115 mA cm^-2,and shows EQE T50 stability around 160 min at 100 mA cm^-2 injection current density.
基金supported by the National Natural Science Foundation of China (21125419, 50990065, 51010003, 51073058, and 20904011)National Research Project (2009CB623601 and 2009CB930604)
文摘A series of alkali metal salts doped pluronic block copolymer F127 were used as electron injection/transport layers (ETLs) for polymer light-emitting diodes with poly[2-(4-(3′,7′-dimethyloctyloxy)-phenyl)-p-phenylenevinylene] (P-PPV) as the emission layer. It was found that the electron transport capability of F127 can be effectively enhanced by doping with alkali metal salts. By using Li2CO3 (15%) doped F127 as ETL, the resulting device exhibited improved performance with a maximum luminous efficiency (LE) of 13.59 cd/A and a maximum brightness of 5529 cd/m2, while the device with undoped F127 as ETL only showed a maximum LE of 8.78 cd/A and a maximum brightness of 2952 cd/m2. The effects of the doping concentration, cations and anions of the alkali metal salts on the performance of the resulting devices were investigated. It was found that most of the alkali metal salt dopants can dramatically enhance the electron transport capability of F127 ETL and the performance of the resulting devices was greatly improved.
基金supported by the National Basic Research Program of China(Grant Nos. 2013CB934500 and 2012CB921302)the National Natural Science Foundation of China (Grant No. 91223204)the "100 Talents Project" of Chinese Academy of Sciences
文摘Carbon-based spintronics refers mainly to the spin injection and transport in carbon materials including carbon nanotubes,graphene,fullerene,and organic materials.In the last decade,extraordinary development has been achieved for carbon-based spintronics,and the spin transport has been studied in both local and nonlocal spin valve devices.A series of theoretical and experimental studies have been done to reveal the spin relaxation mechanisms and spin transport properties in carbon materials,mostly for graphene and carbon nanotubes.In this article,we provide a brief review on spin injection and transport in graphene,carbon nanotubes,fullerene and organic thin films.
