张耿民
纳米材料的制备及其场发射特性
个性化签名
- 姓名:张耿民
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学术头衔:
博士生导师
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学科领域:
凝聚态物理学
- 研究兴趣:纳米材料的制备及其场发射特性
张耿民,男,1969年出生。于1991年和1996年在北京大学电子学系分别获得理学学士和理学博士学位。现任信息科学与技术学院教授,中国真空学会副秘书长。研究方向: 纳米材料的制备及其场发射特性。曾经从事过的研究领域主要包括:(1)寻找能够用于自由电子激光器的新型光电阴极。(2)用有机分子在固液界面制备纳米线并用扫描隧道显微镜进行观察。(3)用场发射显微镜和场离子显微镜研究碳纳米管的端口结构和电子发射性能。目前正在研究各种纳米线阵列的场发射特性,以获得可以用于新一代显示器的场发射电子源。
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504
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成果数
15
【期刊论文】Cupric oxide nanoflowers synthesized with a simple solution route and their field emission
张耿民, Ligang Yu, Gengmin Zhang*, Yue Wu, Xin Bai, Dengzhu Guo
Journal of Crystal Growth 310(2008)3125-3130,-0001,():
-1年11月30日
Assemblies of flower like cupric oxide nanostructures (CuO nanoflowers) were synthesized directly on Cu plates in KOH solution at room temperature. These nanoflowers are believed to have been the result of processes such as oxidation, complex formation, condensation, Ostwald ripening and dissolution Each nanoflower contained a very large number of nanometer scaled flakes (petals) and each petal further branched into tips at its end. The sharpness of these tips resulted in a sufficiently high field enhancement factor. Field emission was available from the CuO nanoflowers and the turn on field was about 8.5V/um. Compared with other methods for fabricating CuO field emitter, this solution route featured remarkable simplicity and cheapness.
A1., Nanostructures, B1., Oxides
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【期刊论文】Field emission from zinc oxide nanostructures and its degradation
张耿民, Jing Xiao, Gengmin Zhang*, Xin Bai, Ligang Yu, Xingyu Zhao, Dengzhu Guo
Vacuum 83(2009)265-272,-0001,():
-1年11月30日
Arrays of zinc oxide (ZnO) nanowires and nanobelts were synthesized by the thermal evaporation of mixed powders of ZnO and graphite. Neither catalyst nor vacuum environnmnt was involved in the fabrication. For comparison, the ZnO nanowires were grown on a pre deposited transitional ZnO fihi1 on a brass substrate and the ZnO nanobelts were grown directly on a Si substrate. Their field emission properties were systematically measured. Current density of 10uA/cm2 was achieved at the fields of 5.7 and 6.2V/um from the nanowires and nanobelts, respectively. Also, the emission sites were found to distribute uniformly on the whole cathode. In the preliminary test on the stability, the ZnO nanobelts, which were sharp at the tip but wide at the root, exhibited better robustness than the ZnO nanowires. The post test scanning electron microscopy (SEM) observation showed that the degradation of their field emission capability resulted from the breaking of the nanowires, which was tentatively attributed to the resistive heating during the field emission. In contrast, the shedding of the ZnO from the substrate was not so serious as imagined.
ZnO nanostructure, Field emission, Degradation
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【期刊论文】Field emission properties of zinc oxide nanowires fabricated by thermal evaporation
张耿民, Weiwei Wang, Gengmin Zhang*, Ligang Yu, Xin Bai, Zhaoxiang Zhang, Xingyu Zhao
Physica E36(2007)86-91,-0001,():
-1年11月30日
Arrays of randomly oriented zinc oxide (ZnO) nanowires were fabricated on silicon wafers via a simple thermal evaporation method. During the fabrication, the temperature around the substrate was below 500°C. The products were analyzed by conventional means and determined to be single crystals of wurtzite-type ZnO that grew along the c-axis. These nanowires were 10-100nm in diameter and 10-100um in length, suggesting a possible high field enhancement factor. The dependence of the field emission current on the anode-cathode voltage (I-V behavior) of the ZnO nanowire arrays was measured in a lab-built ultrahigh vacuum system with a base pressure of 10-7Pa. After surface cleaning by heat treatment, two characteristic electric fields, under which 10uA/cm2 and 1mA/cm2 current densities were extracted, were measured to be 4.0 and 4.7V/um, respectively. As observed with a transparent anode, emission occurred uniformly over the whole sample surface. A 72h-long test on emission stability was performed under a constant voltage of 2.75kV. The current dropped occasionally to approximately 80% of the initial value during the test owing to the poor adherence of the nanowires to the substrate. These preliminary results have shown the perspective of, as well as a major drawback to, a ZnO nanowire array being developed into a cold electron source to be used in future electronic devices
Zinc oxide nanowire, Field emission, Thermal evaporation, Silicon substrate, Adherence
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张耿民, Ligang Yu, Gengmin Zhang*, Shiqi Li, Zhonghe Xi, Dengzhu Guo
Journal of Crystal Growth 299(2007)184-188,-0001,():
-1年11月30日
Arrays of zinc oxide (ZnO) nanorods have been synthesized on silicon substrates by a solution route under an external voltage. They were ~102nm in diameter and grew along the c-axis. Meanwhile, ZnO nanotubes were also obtained. Some comparative experiments showed that applying the external voltage effectively improved the alignment of the ZnO nanorods and enhanced their adherence to the substrates. The role of the external voltage is discussed in terms of the electric field established in the solution and the electrochemical reaction at the cathode. The formation of the nanotubes is attributed to the decrease of the precursor concentration and the disparity between the field strengths at different parts of the ZnO nanorods.
A1., Nanostructures, B1., Oxides
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【期刊论文】Growth of hexagonal tungsten trioxide tubes
张耿民, Yue Wu, Zhonghe Xi, Gengmin Zhang, Jie Yu, Dengzhu Guo
Journal of Crystal Growth 292(2006)143-148,-0001,():
-1年11月30日
A simple approach to fabricating tungsten trioxide robes was developed. Tungsten wires were heated at aronnd 800°С in a hnmid argon flow and hexagon-shaped robes with well faceted end and side surfaces resnlted. As observed with a scanning electron microscope (SEM), the robes were about 1um in cross-sectional dimension and 10um in length. The selected-area electron diffraction (SAED) pattern obtained in the transmission electron microscopy (TEM) study revealed that the robes were hexagonal tungsten trioxide (h-WO3) crystals. The formation of the well-faceted tubular structure is attribnted to the lateral coalescence of WO3 nanowires accompanied with a dehydration process.
A1., Low dimensional structures, B1., Oxides
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【期刊论文】Fabrication of lithium-doped zinc oxide film by anodi coxidation and its ferroelectric behavior
张耿民, Ligang Yu, Gengmin Zhang*, Xingyu Zhao, Dengzhu Guo
Materials Research Bulletin 44(2009)589-593,-0001,():
-1年11月30日
A lithium doped zinc oxide (ZnO) film was obtained by the anodic oxidation of a zinc sheet in a lithium hydroxide (LiOH) solution under an external DC voltage. The formation of the ZnO film on the surface of the Zn sheet is attributed to two simultaneous processes: the electrochemical oxidation of Zn to ZnO, and the chemical dissolution of ZnO. It was also confirmed that Li element was successfully introduced into the lattice of the ZnO film. The curves of the polarization versus applied field were measured to be hysteresis loops, suggesting ferroelectricity of the Li doped ZnO film. Tile remanent polarization and the coercive field of the film were measured to be 4.7x10-3Cm-2 and 1.2x10 7Vm-1 respectively. This ferroelectricity is believed to be the result of the occupation of off centered positions in oxygen tetrahedra by the Li* ions.
A., Oxides, D., Ferroelectricity
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57浏览
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【期刊论文】Field Emission from Carbon Nanotube Arrays Fabricated by Pyrolysis of Iron Phthalocyanine
张耿民
,-0001,():
-1年11月30日
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