通过改变处理衬底表面的方法,制备出不同的微米金刚石薄膜。具体的方法是利用磁控溅射在陶瓷衬底上面镀上一层厚金属钛,对金属钛层进行不同的表面处理后,放在微波等离子体化学气相沉积腔中制备微米金刚石薄膜。对不同的薄膜用二极管型...通过改变处理衬底表面的方法,制备出不同的微米金刚石薄膜。具体的方法是利用磁控溅射在陶瓷衬底上面镀上一层厚金属钛,对金属钛层进行不同的表面处理后,放在微波等离子体化学气相沉积腔中制备微米金刚石薄膜。对不同的薄膜用二极管型结构测试了它们的场致发射电子的性能,良好的表面处理能达到在电场2.1 V/μm下,9.2 m A/cm^2优秀的发射效果。并对发射机理和场发射特性进行了深入的研究。展开更多
A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 wh...A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 when the applied gate voltage is 570 V.Part of the anode current is contributed by the secondary electron emission which is excited from the MgO layer inside the gate apertures on the gate plate. The average emission current density and luminance are 0.47 mA/cm2 and 1 250 cd/m2 respectively with a fluctuation of about 10% during the 1 000 min measurement.By a finite element method calculation the gated structure shows a good electron beam focusing property. The driving performance of the backlight unit is characterized by SPICE simulation tools and measured by the oscilloscope. Stable field emission line-by-line scanning and fast response characteristics of the backlight unit indicate its promising application in the liquid crystal displays.展开更多
Double-walled carbon nanotubes （DWCNTs） with high graphitization have been synthesized by hydrogen arc discharge. The obtained DWCNTs have a narrow distribution of diameters of both the inner and outer tubes, and mo...Double-walled carbon nanotubes （DWCNTs） with high graphitization have been synthesized by hydrogen arc discharge. The obtained DWCNTs have a narrow distribution of diameters of both the inner and outer tubes, and more than half of the DWCNTs have inner diameters in the range 0.6-1.0 nm. Field electron emission from a DWCNT cathode to an anode has been measured, and the emission current density of DWCNTs reached 1 A/cm2 at an applied field of about 4.3 V/~tm. After high-temperature treatment of DWCNTs, long linear carbon chains （C-chains） can be grown inside the ultra-thin DWCNTs to form a novel C-chain@DWCNT nanostructure, showing that these ultra-thin DWCNTs are an appropriate nanocontainer for preparing truly one-dimensional nanostructures with one-atom-diameter.展开更多
Nano-porous ultra-high specific surface ul- trafine fibers are created by the method of “electrospin- ning-phase separation-leaching” (EPL) for the first time. First of all, polymer solutions of polyacrylonitrile (P...Nano-porous ultra-high specific surface ul- trafine fibers are created by the method of “electrospin- ning-phase separation-leaching” (EPL) for the first time. First of all, polymer solutions of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) blends dissolved in co-solvent are electrospun to make ultrafine fibers when charged to high voltages. The incompatibility of PAN and PVP induces phase separation to form microdomains of PVP in the poly- mer blend ultrafine fibers. Then, PVP microdomains in the blend fibers are leached out in water, and porous PAN ul- trafine fibers are obtained. Lastly, the surface and cross-section of the porous ultrafine fibers are observed in detail by field emission scanning electron microscope (FE- SEM), and the specific surface of the ultrafine fibers is measured by means of nitrogen absorption. With increasing the content of PVP, the specific surface area of the ultrafine fibers increases apparently. The specific surface area of the porous ultrafine fibers with the diameter of 2130 nm is more than 70 m2·g?1. The cross-section of the PAN porous ultrafine fibers after leaching of PVP microdomains from polymer blend fibers with the feed ratio of PAN/PVP of 10/20 shows the characteristic of porous structure with pore diameter of ca 30 nm according to FESEM photo.展开更多
文摘通过改变处理衬底表面的方法,制备出不同的微米金刚石薄膜。具体的方法是利用磁控溅射在陶瓷衬底上面镀上一层厚金属钛,对金属钛层进行不同的表面处理后,放在微波等离子体化学气相沉积腔中制备微米金刚石薄膜。对不同的薄膜用二极管型结构测试了它们的场致发射电子的性能,良好的表面处理能达到在电场2.1 V/μm下,9.2 m A/cm^2优秀的发射效果。并对发射机理和场发射特性进行了深入的研究。
基金The National Basic Research Program of China(973 Program)(No.2013CB328803)the National Natural Science Foundation of China(No.51002031)+1 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No.20100092120022)the National High Technology Research and Development Program of China(863 Program)(No.2012AA03A302,2013AA011004)
文摘A zinc oxide ZnO field emitter-based backlight unit for liquid crystal display with a gated structure is fabricated by screen-printing processes.The measured anode field emission current density reaches 0.62 mA/cm2 when the applied gate voltage is 570 V.Part of the anode current is contributed by the secondary electron emission which is excited from the MgO layer inside the gate apertures on the gate plate. The average emission current density and luminance are 0.47 mA/cm2 and 1 250 cd/m2 respectively with a fluctuation of about 10% during the 1 000 min measurement.By a finite element method calculation the gated structure shows a good electron beam focusing property. The driving performance of the backlight unit is characterized by SPICE simulation tools and measured by the oscilloscope. Stable field emission line-by-line scanning and fast response characteristics of the backlight unit indicate its promising application in the liquid crystal displays.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 10974131）, the Nanotechnology Program of Shanghai Science and Technology Committee （No. 0952nm07100）, the Scienceand Technology Innovation Fund of the Shanghai Education Committee （No. 09ZZ85） and Shanghai Pujiang Talent Plan （No. 08PJ1405100）. We thank Professor Shoushan Fan of Tsinghua-Foxconn Nanotechnology Research Center for the HRTEM measurements, and Professor Pingheng Tan of the Institute of Semiconductors for some of the Raman measurements.
文摘Double-walled carbon nanotubes （DWCNTs） with high graphitization have been synthesized by hydrogen arc discharge. The obtained DWCNTs have a narrow distribution of diameters of both the inner and outer tubes, and more than half of the DWCNTs have inner diameters in the range 0.6-1.0 nm. Field electron emission from a DWCNT cathode to an anode has been measured, and the emission current density of DWCNTs reached 1 A/cm2 at an applied field of about 4.3 V/~tm. After high-temperature treatment of DWCNTs, long linear carbon chains （C-chains） can be grown inside the ultra-thin DWCNTs to form a novel C-chain@DWCNT nanostructure, showing that these ultra-thin DWCNTs are an appropriate nanocontainer for preparing truly one-dimensional nanostructures with one-atom-diameter.
文摘Nano-porous ultra-high specific surface ul- trafine fibers are created by the method of “electrospin- ning-phase separation-leaching” (EPL) for the first time. First of all, polymer solutions of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) blends dissolved in co-solvent are electrospun to make ultrafine fibers when charged to high voltages. The incompatibility of PAN and PVP induces phase separation to form microdomains of PVP in the poly- mer blend ultrafine fibers. Then, PVP microdomains in the blend fibers are leached out in water, and porous PAN ul- trafine fibers are obtained. Lastly, the surface and cross-section of the porous ultrafine fibers are observed in detail by field emission scanning electron microscope (FE- SEM), and the specific surface of the ultrafine fibers is measured by means of nitrogen absorption. With increasing the content of PVP, the specific surface area of the ultrafine fibers increases apparently. The specific surface area of the porous ultrafine fibers with the diameter of 2130 nm is more than 70 m2·g?1. The cross-section of the PAN porous ultrafine fibers after leaching of PVP microdomains from polymer blend fibers with the feed ratio of PAN/PVP of 10/20 shows the characteristic of porous structure with pore diameter of ca 30 nm according to FESEM photo.
