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ZnO nanorod arrays:Field-assisted growth in aqueous solution and field emission properties

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Science China(Technological Sciences) 2012年第11期55卷 3176-3186页

作者： YIN JianBo zhang gengmin Key Laboratory.tbr the Phystcs and Chemtstry of Nanodevlces and Department of Electronics Peking UniversityBeijing 100871China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China

ZnO nanorod arrays were fabricated in aqueous solutions under external *** morphology and length of the nanorods could be readily controlled by varying such parameters as the voltage magnitude,growth time,solution concentration and substrate *** external voltage,which made the adsorption of the Zn 2+ cation-containing complexes more possible,modified the growth behavior of the ZnO crystals and played a key role in guaranteeing the orderliness of the *** increase in the nanorod length with the prolonged growth time gradually saturated due to the balance between the growth and the *** ZnO nanorods respectively grown on the Zn and Si substrates differed considerably in both morphology and defect *** emission was extracted from arrays of nanorods with tapered *** field-assisted solution route for fabricating ZnO nanorods featured simplicity in manipulation,inexpensiveness in instrumentation,and effectiveness in controlling the morphology and length.

关键词： ZnO nanorod field-assisted solution method field emission

Direct growth of tungsten oxide nanorods from heated tungsten foils

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Science China(Technological Sciences) 2012年第6期55卷 1503-1508页

作者： QIN JingFang zhang gengmin XING YingJie Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking UniversityBeijing 100871China Academy for Advanced Interdisciplinary Studies Peking UniversityBeijing 100871China

Tungsten oxide （W18O49） nanorods were grown by directly heating tungsten foils covered with potassium bromide （KBr） in low-pressure wet oxygen. The approach featured such advantages as convenient manipulation, low cost and rapid accessibility to high temperatures. A solid-liquid-solid （SLS） mechanism is believed to have dominated the growth process, in which the W18049 nanorods segregated from eutectic droplets of potassium tungstate and tungsten oxide. The ultraviolet photoelectron spectroscopy （UPS） analysis disclosed that the valence band maximum （VBM） of these nanorods was approximately 9 eV be- low the vacuum level. The feasibility of using the such-fabricated nanorods as field emitters was tested and the related mecha- nism was also discussed.

关键词： W18049 fast heating CVD field emission

Ultrathin ZnO membranes a few atomic layers in thickness

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Science China(Technological Sciences) 2014年第2期57卷 315-321页

作者： YIN JianBo XIA HuaRong LIANG Jia zhang gengmin Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Academy for Advanced Interdisciplinary Studies Peking University

For the first time we fabricated ZnO membranes with thicknesses of 2.4 nm by a facile one-pot synthesis in aqueous *** crystal analysis revealed that the hexagonal ZnO membranes were about 10 atomic layers in *** ZnO membranes bent,scrolled,intersected with each other,and self-assembled to particles in micrometre *** hierarchical assemblies showed sponge-like structures with room *** the growth process,a cationic polyelectrolyte was utilized to modulate growth behavior of the ZnO *** a result,the preferred growth direction of ZnO membranes is along 0110,which was perpendicular to[0001]growth direction in a typical hydrothermal *** growth mechanism of the membranes was also discussed.

关键词： ZnO 2D materials nanosheets hierarchical structures

Thermionic emission as a tool for measuring the work function of anodic titanium dioxide

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Science China(Physics,Mechanics & Astronomy) 2018年第2期61卷 72-75页

作者： YanHui Chen gengmin zhang Jin Yang Yue Wu Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Chang'an Communication Technology Co. Ltd. College of Engineering Peking University

Titanium dioxide （TiO2） is being extensively applied in such fields as photocatalysis, sensing, photoelectrolysis, and pho- tovoltaics [I]. The work function （WF） of a material is one of the vital factors that determine the performance of this ma- terial in electron emission, chemical reaction, surface atomic reconstruction, trapping, and recombination of photogener- ated electrons and holes, interface interaction, and corrosion resistance [2,3]. The WF of metallic Ti is an old topic and abundant data are available [4-7]. In contrast, reports on the WF of TiO2 are relatively rare [2,3,8-10].

关键词： Thermionic emission anodic titanium dioxide

Modulation of field emission by small AC signals

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Science China(Technological Sciences) 2017年第12期60卷 1897-1902页

作者： YANG Jin zhang gengmin ZHOU HaiTao WEI JinDi CHEN YanHui SHEN ChengMin Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics PekingUniversity Beijing 100871 China Academy for Advanced Interdisciplinary Studies Peking University Beijing 100871 China AECC Beijing Institute of Aeronautical Materials Beijing100095 China Beijing National Laboratory of Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China Chang'an Communication Technology Co. Ltd. Beijing 102209 China

In a microwave tube the energy of electrons in an electron beam, which are usually generated by a thermionic cathode, is modulated such that it is transformed into electromagnetic wave energy. In this paper, we modulated the field emission using AC signals.A field emission current with AC components was attained by adding a small AC voltage to a high extracting DC voltage. We observed two phenomena related to the AC components of the field emission current. First, when the DC component of the extracting voltage was low, the current measured in the circuit was dominated by the displacement current. Second, besides the fundamental frequency component, higher order harmonics were also observed in the field emission current.

关键词： field emission AC modulation displacement current harmonics

UV irradiation induced conductivity improvement in poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) film

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Science China(Technological Sciences) 2014年第1期57卷 44-48页

作者： XING YingJie QIAN MinFang WANG GuiWei zhang gengmin GUO DengZhu WU JinLei Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University

We describe a simple method to increase the conductivity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)film by exposure to ultraviolet(UV)light in *** to four order of conductivity improvement(from 10 3to 50 S/cm)is achieved by irradiating PEDOT:PSS film with 254 nm ultraviolet(UV)*** conductivity in UV treated PEDOT:PSS film is stable under ambient *** mechanism for conductivity improvement is investigated by current-voltage measurement,atomic force microscopy,and absorption ***-cross-linking of PSS chains is determined as the reason for conductivity *** result demonstrates that UV treatment is capable of modifying the conductivity of PEDOT:PSS film independent of the process of film formation.

关键词： conductivity ultraviolet photo-cross-linking

Fabrication of multi-sectional TiO_2 nanotube arrays by anodization

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Science China Chemistry 2010年第5期53卷 1067-1072页

作者： LI ShiQi,YIN JianBo & zhang gengmin Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics,Peking University,Beijing 100871,China Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing China

We report a facile method to grow multi-sectional TiO2 nanotube arrays consisting of alternating bamboo-shaped and smooth-walled nanotube sections by *** key factors are necessary for obtaining these ***,in order to avoid possible disruptions between the conjoint sections of the nanotube,the distribution of hydrogen ions is suggested not to be fiercely disturbed when switching from the first to the second ***,to avoid the disruption of the nanotube at the joint which results from the disparity in diameters between sections,the direct current voltage is set to be the maximum of the square wave *** newly developed TiO2 nanotube arrays are expected to have potential applications in solar cells,drug release and delivery systems.

关键词： titanium dioxide titania nanotube anodic oxidation

氮离子轰击改善胶体石墨薄膜平面场发射特性的研究

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北京大学学报（自然科学版） 2007年第3期43卷 412-416页

作者：王玮玮孙辉于利刚张耿民北京大学信息科学技术学院电子学系北京100871

研究了氮离子（N^＋）轰击对石墨薄膜场发射特性的影响。片层石墨被N^＋轰击成较整齐排列的锥尖阵列,尖端密度-10^8cm^-2。XPS谱证实有许多N原子注入薄膜,膜内存在大量sp2杂化轨道键。场发射测试表明,经过N＋轰击,整个薄膜在场发射的均... 详细信息

研究了氮离子（N^＋）轰击对石墨薄膜场发射特性的影响。片层石墨被N^＋轰击成较整齐排列的锥尖阵列,尖端密度-10^8cm^-2。XPS谱证实有许多N原子注入薄膜,膜内存在大量sp2杂化轨道键。场发射测试表明,经过N＋轰击,整个薄膜在场发射的均匀一致性方面有较明显的改善,场发射电流密度从0.3增大到1.65 mA/cm^2。

关键词：氮离子(N^+) 溅射轰击石墨场发射阵列

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钨针尖放电处理后的场发射特性

北京大学学报（自然科学版） 2006年第3期42卷 385-387页

作者：陶雄张兆祥王鸣生吴越张耿民教育部纳米器件物理与化学重点实验室北京大学信息科学技术学院电子学系北京100871

在场发射显微镜(FEM)中使用1万伏以上的电压对钨针尖进行了放电处理。扫描电子显微镜(SEM)和透射电子显微镜(TEM)的观察表明在处理后形成了纳米尺寸的突起。从经过处理的钨针尖能够支取高达1.55mA的场发射电流。针尖的场发射像呈现四重... 详细信息

在场发射显微镜(FEM)中使用1万伏以上的电压对钨针尖进行了放电处理。扫描电子显微镜(SEM)和透射电子显微镜(TEM)的观察表明在处理后形成了纳米尺寸的突起。从经过处理的钨针尖能够支取高达1.55mA的场发射电流。针尖的场发射像呈现四重对称,表明它来自单个突起。场发射电流与电压关系符合Fowler-Nordheim(F-N)理论。根据F-N理论算得的场发射面积与TEM下观察到的突起的面积在量级上一致。

关键词：钨针尖场发射电弧放电