nanoquebec 2007-01-03 04:10
今日材料杂志 (MaterialsToday) 2007年V10N1-2
[size=4][color=DarkGreen][b]1. Cover story: [/b][/color][/size][size=3][b][color=DarkGreen]Graphene: carbon in two dimensions[/color][/b][/size][size=3][color=DarkGreen]
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[b]Carbon is one of the most intriguing elements in the Periodic Table, forming many allotropes from diamond and graphite to nanotubes and fullerenes. Yet the two-dimensional form (graphene) was conspicuously missing, resisting any attempt at experimental observation until very recently. Furthermore, graphene – the first truly two-dimensional material – displays some very peculiar electronic properties.[/b]
[i]Mikhail I. Katsnelson[/i]
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Carbon is one of the most intriguing elements in the Periodic Table. It forms many allotropes, some known from ancient times (diamond and graphite) and some discovered 10-20 years ago (fullerenes and nanotubes). Interestingly, the two-dimensional form (graphene) was only obtained very recently, immediately attracting a great deal of attention. Electrons in graphene, obeying a linear dispersion relation, behave like massless relativistic particles. This results in the observation of a number of very peculiar electronic properties – from an anomalous quantum Hall effect to the absence of localization – in this, the first two-dimensional material. It also provides a bridge between condensed matter physics and quantum electrodynamics, and opens new perspectives for carbon-based electronics.
Carbon plays a unique role in nature. The formation of carbon in stars as a result of the merging of three α-particles is a crucial process that leads to the existence of all the relatively heavy elements in the universe1. The capability of carbon atoms to form complicated networks2 is fundamental to organic chemistry and the basis for the existence of life, at least in its known forms. Even elemental carbon demonstrates unusually complicated behavior, forming a number of very different structures. As well as diamond and graphite, which have been known since ancient times, recently discovered fullerenes3, 4 and 5 and nanotubes6 are currently a focus of attention for many physicists and chemists. Thus, only three-dimensional (diamond, graphite), one-dimensional (nanotubes), and zero-dimensional (fullerenes) allotropes of carbon were known. The two-dimensional form was conspicuously missing, resisting any attempt at experimental observation – until recently.
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[url=http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6X1J-4MMXWMN-K-T&_cdi=7244&_user=2101137&_orig=search&_coverDate=02%2F28%2F2007&_qd=1&_sk=999899998&view=c&wchp=dGLbVlb-zSkWA&md5=2aa9c22ee6d9f2e0e2aa0dceefa0794c&ie=/sdarticle.pdf]:fulltext[/url]
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[size=4]2.Review:[/size] [/b][/color][/size][size=3][b][color=DarkGreen]Carbon nanotubes – becoming clean[/color][/b][/size][size=3][color=DarkGreen]
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[b]Today, products containing carbon nanotubes (CNTs) range from tennis rackets to vehicle fenders, X-ray tubes, and Li ion batteries. Future applications based on individual nanotubes will require precise characterization of clean CNT material.[/b]
[i]Nicole Grobert[/i]
[quote]
Carbon nanotubes (CNTs) are now well into their teenage years. Early on, theoretical predictions and experimental data showed that CNTs possess chemical and mechanical properties that exceed those of many other materials. This has triggered intense research into CNTs. A variety of production methods for CNTs have been developed; chemical modification, functionalization, filling, and doping have been achieved; and manipulation, separation, and characterization of individual CNTs is now possible. Today, products containing CNTs range from tennis rackets and golf clubs to vehicle fenders, X-ray tubes, and Li ion batteries. Breakthroughs for CNT-based technologies are anticipated in the areas of nanoelectronics, biotechnology, and materials science. In this article, I review the current situation in CNT production and highlight the importance of clean CNT material for the success of future applications.
Carbon fibers and filaments have been studied for over 100 years. Hughes and Chambers1, and Schützenberger and Schützenberger2 reported the growth of filamentous carbon in 1889 and 1890, respectively. In the early 1950s, Radushkevich and Lukyanovich3 published a report on hollow carbon fibers (Fig. 1). Since then, the demand by the space and aerospace industry for stronger, lightweight materials with improved mechanical properties has led to substantial progress in the production and characterization of carbon filaments and hollow carbon fibers.
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[url=http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6X1J-4MMXWMN-M-13&_cdi=7244&_user=2101137&_orig=search&_coverDate=02%2F28%2F2007&_qd=1&_sk=999899998&view=c&wchp=dGLbVlz-zSkWW&md5=4f45bd4826d7e68fac4ebd0fc117c5ec&ie=/sdarticle.pdf]:fulltext[/url]
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[/size][b][size=4]3.Review:[/size] [/b][b]Growth of nanotubes for electronics[/b]
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[b]Carbon nanotubes could find use in future microelectronics devices as vias, interconnects, or field-effect transistors. But this will place a number of requirements on the controlled growth of nanotubes.[/b]
[i]John Robertson[/i]
[quote]
The roadmap for semiconductor devices envisages that carbon nanotubes or semiconducting nanowires could become important in about ten years. This article reviews where carbon nanotubes could contribute to microelectronics, in terms of vias, interconnects, and field-effect transistors. It focuses particularly on the requirements microelectronics places on the growth of nanotubes. That is, control over the formation of semiconducting or metallic tubes, controlling the growth location and direction, and achieving high enough nucleation densities.
Carbon nanotubes (CNTs) have a unique set of properties, including ballistic electron transport and a huge current-carrying capacity, which make them of great interest for future microelectronics. Moore's law describes the evolution and scaling of conventional Si-based field-effect transistor (FET) integrated circuits to ever-smaller feature sizes (Fig. 1). The feature size is presently 65 nm and the gate length of FETs at this node is 32 nm, which is well within the ‘nano’ range. This emphasizes how far the conventional ‘top-down’ fabrication methods of lithography, deposition, and etching can go without asking for a bottom-up approach. But continued scaling is becoming increasingly difficult1 and 2, so that many firms are researching ‘bottom-up’ approaches including CNTs as an option2, 3, 4, 5, 6 and 7. But will they work and what is required for them to be successful? Chau et al.2 indicate that nanotubes and semiconductor nanowires could be of interest from 2012 onwards. One thing in favor of nanotubes is that many new materials other than Si and SiO2 are being introduced into integrated circuits, and the previously conservative outlook of the industry to new materials is changing8 and 9.
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[url=http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6X1J-4MMXWMN-N-N&_cdi=7244&_user=2101137&_orig=search&_coverDate=02%2F28%2F2007&_qd=1&_sk=999899998&view=c&wchp=dGLbVlb-zSkWb&md5=82563408758bfef37108054ebabd24be&ie=/sdarticle.pdf]:fulltext[/url]
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[size=4]4.Review:[/size][/b][b]Diamond-like carbon for data and beer storage[/b]
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[b]The properties of diamond-like carbon films can be tuned for a variety of applications, from hard disk drives to plastic beer bottles.[/b]
[i]Cinzia Casiraghi, John Robertson, and Andrea C. Ferrari[/i]
:nanost
[quote]
Carbon is a very versatile element that can crystallize in the forms of diamond or graphite. There are many noncrystalline carbons, known as amorphous carbons. An amorphous carbon with a high fraction of diamond-like (sp3) bonds is named diamond-like carbon (DLC). Unlike diamond, DLC can be deposited at room temperature. Furthermore, its properties can be tuned by changing the sp3 content, the organization of the sp2 sites, and the hydrogen content. This makes DLC ideal for a variety of different applications. We review the use of ultrathin DLC films for ultrahigh-density data storage in magnetic and optical disks and ultralong beer storage in plastic bottles.
Carbon-based materials play a major role in today's science and technology. Carbon is a very versatile element that can crystallize in the form of diamond and graphite. In recent years, there have been continuous and important advances in the science of carbon such as chemical vapor deposition of diamond1 and the discovery of fullerenes2, carbon nanotubes3 and 4, and single-layer graphene5. There have also been major developments in the field of disordered carbons. In general, an amorphous carbon can have any mixture of sp3, sp2, and even sp1 sites, with the possible presence of hydrogen and nitrogen. The compositions of nitrogen-free carbon films are conveniently shown on a ternary phase diagram ( Fig. 1). An amorphous carbon with a high fraction of diamond-like (sp3) bonds is known as diamond-like carbon (DLC). Unlike diamond, DLC can be deposited at room temperature, which is an important practical advantage. DLCs possess an unique set of properties, which has lead to a large number of applications such as, for example, magnetic hard disk coatings; wear-protective and antireflective coatings for tribological tools, engine parts, razor blades, and sunglasses; biomedical coatings (such as hip implants or stents); and microelectromechanical systems6, 7, 8, 9 and 10.
....[url=http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6X1J-4MMXWMN-P-Y&_cdi=7244&_user=2101137&_orig=search&_coverDate=02%2F28%2F2007&_qd=1&_sk=999899998&view=c&wchp=dGLzVlz-zSkzS&md5=20fe304f4af599be32ae589fbc742c15&ie=/sdarticle.pdf] :ftext [/url]
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[[i] 本帖最后由 nanoquebec 于 2007-01-02 17:11 编辑 [/i]]
hrbustzsh 2007-02-10 10:20
好东西. 开开眼界,谢谢楼主!