<i>In situ</i> observation of field emissions from an individual carbon nanotube by Lorenz microscopy

Fujieda, Tadashi; Hidaka, Kumi; Hayashibara, M.; Kamino, Takeo; Matsumoto, Hiroaki; Ose, Yoichi; Abe, Hidekazu; Shimizu, Toshimi; Tokumoto, Hiroshi

doi:10.1063/1.1834713

Cited by 23 publications

(18 citation statements)

References 5 publications

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“…2.14). In particular, carbon nanotubes, with their extremely strong mechanical structure, high current carrying capacity (10 9 A/cm 2 -orders of magnitude higher than copper and silver), and high aspect ratios, seem like ideal candidates for field-electron emitters [40][41][42][43][44]. Moreover, their unique structure could lead to interesting electron emission characteristics or be used to make more controllable electron emitters.…”

Section: Electron Emitters Electron Emitters Have Long Been In Use Inmentioning

confidence: 99%

Nanoscale Devices: Applications and Modeling

Nojeh

2009

Bio‐Inspired and Nanoscale Integrated Computing

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Section: Electron Emitters Electron Emitters Have Long Been In Use Inmentioning

confidence: 99%

Nanoscale Devices: Applications and Modeling

Nojeh

2009

Bio‐Inspired and Nanoscale Integrated Computing

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“…[6][7][8][9][10][11][12] However, it is likely that the observed structural changes do not arise from "pure" field evaporation phenomena. The reason for this is that when CNTs are negatively charged, the large field-emission current can induce very irregular tip structures and can even damage the emitters.…”

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confidence: 99%

Grinding a Nanotube

2008

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Field evaporation phenomena, the removal of atoms from positively charged surfaces at strong field of tens of volts per nanometer, are of tremendous scientific and technological importance. The technique of field-ion microscopy (FIM) has been developed based on this phenomenon, and is historically the first technique to have achieved atomic resolution. [1,2] The atom probe, a variation of FIM, came later and is generally used to identify the species of atoms that are being individually evaporated from the surface of a FIM tip. [2] Recently, atom-probe tomography (APT) [3,4] has been developed as a powerful analytical characterization technique that ties compositional information to structure. This is the only approach that is capable of determining the 3D location and elemental identity of atoms in a sample with near atomic precision. In principle, the field evaporation phenomenon can be utilized not only for materials characterization, but also for materials processing and morphology control with extremely high precision because of its unique atom-by-atom removal capability. However, FIM and atom probe investigations only provide access to structural information on the tip surface or the evaporated segments of the specimen, and it is not possible to directly observe the structural evolution of the sample. This limitation has greatly restricted the potential applications of field evaporation as a materials-processing tool.Here, we have investigated the positive field evaporation of nanomaterials by transmission electron microscopy (TEM). Direct TEM observations of the details of the structural evolution during field evaporation have been obtained for the first time. In previous work, the shortening of individual positively biased carbon nanotubes (CNTs) has been observed by scanning electron microscopy (SEM), [5] but the observed phenomenon may perhaps arise from the electron ablation effect because of electrons emitted from the counter CNT electrodes. Detailed information about the end caps of CNTs is difficult to obtain because of the limited spatial resolution of SEM. On the other hand, structural changes in individualCNTs have also been observed in previous in situ field-emission measurements. [6][7][8][9][10][11][12] However, it is likely that the observed structural changes do not arise from "pure" field evaporation phenomena. The reason for this is that when CNTs are negatively charged, the large field-emission current can induce very irregular tip structures and can even damage the emitters. In contrast, as will be demonstrated here, positive field evaporation is much more controllable. Indeed, we demonstrate that positive field evaporation in combination with in situ TEM may actually provide a very simple and effective means for controlling the morphology of nanomaterials with atomic precision. All the in situ experiments have been carried out using a 200 kV Tecnai G20 transmission electron microscope with a vacuum level of about 1×10 -5 Pa. The manipulations and measurements have been made using a Nanof...

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“…Electromagnetic shielding and absorbing by walls outside the building are widely applied to protect or camouflage electronic equipment. For example, the multilayer-substrate structure walls [11], the multi-walled carbon nanotubes [12], or the walls filled by absorption material composed of a multi-layer hollow globule of carbon [13]. These kinds of walls usually have very good absorbing effectiveness.…”

Section: Introductionmentioning

confidence: 99%

Design and optimize spherical particle absorber by Fe-rich hollow cenosphere of fly-ash for broadband electromagnetic wave absorbing wall

Tang

Wang

et al. 2015

IEICE Electron. Express

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In this paper, the absorbing effectiveness of spherical particle absorber made of cheap Fe-rich hollow cenosphere fly-ash is analyzed. The effects of the diameter of spheres, the number of layer and the stack modes of sphere particle on the absorbing effectiveness were explored. Based on the results, a three-layer structure with mixed sizes of spheres was designed, constructed and tested. Obtained results show that this structure has a maximal reflection loss of 9 dB and the bandwidth being higher than 5 dB is more than 17 GHz. When applying the permittivity of Fe-rich hollow cenosphere fly-ash, and the thickness of absorber is 6.5 cm, the maximal reflection loss is 23 dB and the bandwidth being lower than −10 dB is more than 14 GHz, which covers the C, X and Ku bands. The experimental test proved that the three-layer structure absorber has good absorbing effectiveness.

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In situ observation of field emissions from an individual carbon nanotube by Lorenz microscopy

Cited by 23 publications

References 5 publications

Nanoscale Devices: Applications and Modeling

Nanoscale Devices: Applications and Modeling

Grinding a Nanotube

Design and optimize spherical particle absorber by Fe-rich hollow cenosphere of fly-ash for broadband electromagnetic wave absorbing wall

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