Nanostructured Carbon Electron Emitters and Their Applications
Yahachi Saito, Yahachi Saito
- 360 Seiten
- English
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Nanostructured Carbon Electron Emitters and Their Applications
Yahachi Saito, Yahachi Saito
Über dieses Buch
Carbon forms a variety of allotropes due to the diverse hybridization of s- and p-electron orbitals, including the time-honored graphite and diamond as well as new forms such as C 60 fullerene, nanotubes, graphene, and carbyne. The new family of carbon isotopes—fullerene, nanotubes, graphene, and carbyne—is called "nanostructured carbon" or "nanocarbon." These isotopes exhibit extreme properties such as ultrahigh mechanical strength, ultrahigh charge–carrier mobility, and high thermal conductivity, attracting considerable attention for their electronic and mechanical applications as well as for exploring new physics and chemistry in the field of basic materials science. Electron sources are important in a wide range of areas, from basic physics and scientific instruments to medical and industrial applications. Carbon nanotubes (CNTs) and graphene behave as excellent electron-field emitters owing to their exceptional properties and offer several benefits compared to traditional cathodes. Field emission (FE) produces very intense electron currents from a small surface area with a narrow energy spread, providing a highly coherent electron beam—a combination that not only provides us with the brightest electron sources but also explores a new field of electron beam–related research.
This book presents the enthusiastic research and development of CNT-based FE devices and focuses on the fundamental aspects of FE from nanocarbon materials, including CNTs and graphene, and the latest research findings related to it. It discusses applications of FE to X-ray and UV generation and reviews electron sources in vacuum electronic devices and space thrusters. Finally, it reports on the new forms of carbon produced via FE from CNT.
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Information
Chapter 1 FEM and FIM of Carbon Nanotubes
1.1 Structure of CNT and Electron Emission Properties
Value | Reference | |
---|---|---|
Work function | ||
SWCNT | 4.7 eV (contact pot. difference) | X. Cui et al., Nano Lett. 3 (2003), 783 |
4.8 eV (photoelectron emission) | S. Suzuki et al., Appl. Phys. Lett. 76 (2000), 4007 | |
MWCNT | 4.3 eV (photoelectron emission) | H. Ago et al., J. Phys. Chem. B, 103 (1999), 8116 |
4.6–4.8 eV (contact pot. difference) | R. Gao et al., Appl. Phys. Lett. 78 (2001), 1757 | |
4.51–4.78 eV (field emission) | Z. Xu et al. Appl. Phys. Lett. 87 (2005), 163106 | |
SWCNT, DWCNT, MWCNT bundles | 4.7–4.9 eV (thermionic emission from side wall) | P. Liu et al., Nano Lett. 8 (2008), 647 |
Electrical resistance | ||
Individual SWCNT | ~ 7 kΩ/μm (bridged single tube) | S. Li et al., Nano Lett. 4 (2004), 2003 |
Electrical resistivity | ||
Aligned SWCNT film | ≲ 5.5 × 10−4 Ω-cm (// alignment) | J. E. Fisher et al., J. AppL Phys. 93 (2003), 2157 |
≲ 3.4 × 10−3 Ω-cm (⊥) | ||
Aligned SWCNT rope | 0.825 × 10−3 Ω-cm (// rope) at RT | J. Hone et al., Appl. Phys. Lett. 77 (2000), 667 |
5.0 × 10−3 Ω-cm (⊥) at RT | ||
Individual MWCNT | Longitudinal (// c-plane) | |
Resistivity ρ = 10−5–10−4 Ω-cm | T. W. Ebbesen et al., Nature 382 (1996), 54 | |
Transversal (⊥ c-plane) | ||
Intershell conductance 4.5 mS/μm for d = 33 nm | A. Stetter et al., Phys. Rev. B 82 (2010), 115451 | |
13–19 mS/μm for d = 13–18 nm (270–350 mS/μm2) | Y. Shinomiya et al., Surf Interface Anal. 48 (2016), 1206 | |
Intershell resistivity | ||
≈ 3 Ω-cm for d = 30 nm | A. Stetter et al., Appl. Phys. Lett. 93 (2008) 172103 | |
= (0.8–1.1) × 10−3 Ω-cm at high temp. | Y. Shinomiya et al., unpublished | |
cf. Graphite | In-plane resistivity ~5 × 10−5 Ω-cm | K. Matsubara et al., Phys. Rev. B 41 (1990), 969 |
c-axis resistivity ~10−3 Ω-cm for natural and synthetic single crystal | ||
~10−2–100 Ω-cm for HOPG | ||
Max. current | ||
SWCNT in vacuum | >20 μA (109 A/cm2) on SiO2/Si | Z. Yao et al., Phys. Rev. Lett. 84 (2000), 2941 |
MWCNT in vacuum | > 109 A/cm2 on SiO2/Si | B. Q. Wei et al., Appl. Phys. Lett. 79 (2001), 1172 |
~2 × 109 A/cm2 on Si3N4 membrane | G. E. Begtrup et al., Phys. Rev. Lett. 99 (2007), 155901 | |
~0.7–0.35 × 109 A/cm2 suspended | K. Yamauchi et al., unpublished | |
(decrease with the increase of layer number from 6 to 13) | ||
Carrier mobility (FET) of SWCNT | ≈ 100 cm2/Vs (isolated on SiO2) | F. Nihey et al., Jpn. J. AppL Phys., 42 (2003), L128 |
~10... |