Stable field emission from tetrapod-like ZnO nanostructures

Li, Q. H.; Wan, Qing; Chen, Y. J.; Wang, T. H.; Jia, Hongbo; Yu, Dapeng

doi:10.1063/1.1773613

Cited by 144 publications

(74 citation statements)

References 19 publications

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“…10 The variety of ZnO nanostructures has provided strong potential in the application of nanoscale devices. One-dimensional (1-D) ZnO nanostructures have been demonstrated in the nanolasings, 11 nanoresonators, 12 photonic crystals, 13 photodetectcors, 14 optical modulator waveguides, 15 light-emitting diodes, 16 field emitters, 17 gas sensors, 18 solar cells, 19 and so on. However, the characteristics of the nanodevices depend significantly on the shape and size of the nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Integration of ZnO Nanotubes with Well-Ordered Nanorods through Two-Step Thermal Evaporation Approach

et al. 2007

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We have successfully realized the integration of ZnO nanotubes and well-ordered nanorods through a simple two-step thermal evaporation of Zn powder without any metal catalyst. Detailed structural analysis shows that the step-one prepared samples at the low substrate temperature are composed of hexagonal-shaped Zn/ Zn suboxide nanowires dominated by Zn with little oxidation via the layer-by-layer growth mechanism. In the second step, by heating the step-one deposited samples and Zn powder at high temperature, highly ordered single-crystalline ZnO nanorods were epitaxially grown on the surface of nanowires through the screw dislocation growth mode. Simultaneously, Zn inside the nanowires sublimates to form hollow ZnO nanotubes, which finally results in the formation of ZnO nanotubes surrounded by well-ordered nanorods (ZNSWN). The field-emission scanning electron microscopy images of samples with different heating times indicate that the length of ZnO nanorods in the tube walls can be well controlled by changing the reaction time with a growth rate of ∼3 nm/min. We also further present the comparative X-ray diffraction, Raman, and photoluminescence investigation for the growth process and structural information of the fabricated ZNSWN nanostructures.

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Section: Introductionmentioning

confidence: 99%

Integration of ZnO Nanotubes with Well-Ordered Nanorods through Two-Step Thermal Evaporation Approach

et al. 2007

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“…S3 of the Supporting Information). [36] Figure 3c and 3d shows typical current-density-electric-field characteristics. The turn-on field (E to ) and the threshold field (E thr ) are the electric fields required to produce a current density of 10 mA cm À2 and 10 mA cm À2 , respectively.…”

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confidence: 97%

ZnS Branched Architectures as Optoelectronic Devices and Field Emitters

et al. 2010

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Branched assemblies of nanostructures (nanocrystals, nanowires, nanobelts and nanotubes) as building blocks for functional materials and devices are the key to tailoring properties for specific applications in micro-/nanoelectromechanical systems, optoelectronics, field emitters, and light-emitting diodes. [1][2][3][4][5] Direct fabrication of complex nanostructures with controlled structural characteristics (including morphology, dimensionality, surface architectures, and crystal structures) represents a significant challenge in the field of nanometer-scale science and technology. Intensive efforts have been devoted to achieving desired morphology or shape (such as cones, spheres, tubes, wires, belts, cables, and branched heterostructures) and crystallinity of various inorganic crystals-from micrometer to nanometer size. Such structural parameters represent key elements that determine their electrical, optical, and field-emission (FE) properties. High-quality field emitters are very desirable for applications in a wide range of FE-based devices such as flat-panel displays, parallel-electron-beam microscopes, vacuum microwave amplifiers, and X-ray sources. To date, various FE cold cathode 1D nanostructural materials, such as carbon nanotubes, ZnO, ZnS, Si, SiC, CdS, and AlN nanostructures, have been demonstrated as candidates for achieving a high FE-current density at low electric fields because of their high aspect ratios.[6] Especially, branched nanostructures with a high packing density and highly crystalline nanotips can significantly enhance their FE properties and thus show great promising for practical applications. Recently, special architectures, such as AlN nanoarchitectures, [2] comblike ZnO nanostructures, [7] ZnO nanoarchitectures, [8] cactus-like Ga 2 O 3 Nanostructures, [9] CdTe architectures, [10] and branched ZnS-In heterostructures, [11] have been observed and have shown improved FE properties.ZnS, a wide bandgap semiconductor with a gap energy of 3.7 eV at 300 K, is one of the first discovered compound semiconductors and probably one of the most important materials in electronic/optoelectronic industries with prominent applications in flat-panel displays, sensors, lasers, and photocatalysis. [12,13] Interest in FE from ZnS has been increasing because of its charming performance. Many studies have been reported on manipulating the size, morphology, and crystal structure of ZnS materials for optimizing their FE properties, and various ZnS nanostructures, such as rods, [14] wires, [15] belts, [16][17][18] cables, [19,20] tubes, [21] tetrapods, [22] helices, [23] and conelike structures, [24][25][26] are synthesized. However, understanding of self-assembled single-phased ZnS branched architectures and their associated FE properties is limited, [11] although such information is vital for their potential applications.In this Communication, we report a novel single-phased ZnS branched architecture, self-assembled through a facile thermal evaporation process. This novel architecture consists of a singl...

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“…Novel tetrapod-like structures, constructed from 1D nanorods, have been observed in almost all the binary II-VI compounds, [3][4][5][6][7][8][9][10][11][12] but have not been in their ternary alloys. It has also been demonstrated that these tetrapod nanocrystals have many potential applications in waveguides, [13] photodiodes, [14] transistors, [15] field emission devices, [16] gas sensors, [17] and biomolecule delivery. [18] T-ZnSSe nanostructures were synthesized by thermally evaporating Zn powder and some group VI source materials, including S, Se and SeS 2 , in a horizontal tube furnace (see the experimental section).…”

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confidence: 99%