Carbon Nanotube-Based Nonvolatile Random Access Memory for Molecular Computing

Rueckes, Thomas; Kim, Kyoungha; Joselevich, Ernesto; Tseng, Greg Y.; Cheung, Chin Li; Lieber, Charles M.

doi:10.1126/science.289.5476.94

Cited by 1,650 publications

(912 citation statements)

References 25 publications

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“…In particular, when an electric field passes through a nanotube that is stood on its end, the sharp nanotube tip concentrates the electrons and rapidly projects them onto a target. 50 As circuit miniaturization progresses, SWNTs offer the attractive advantage that they can act as metallic nanowires that have the potential to significantly impact the fields of energy storage 64 and molecular electronics [65][66][67][68][69] ( Figure 1 -5). NDC is observed for metallic nanotubes at low electric fields, which is significant for electronic applications and holds general implications for high-current applications based on 1D materials.…”

Section: Electronic Properties and Applicationsmentioning

confidence: 99%

Photophysics of Individual Single-Walled Carbon Nanotubes

2008

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Single-walled carbon nanotubes (SWNTs) are cylindrical graphitic molecules that have remained at the forefront of nanomaterials research since 1991, largely due to their exceptional and unusual mechanical, electrical, and optical properties. The motivation for understanding how nanotubes interact with light (i.e., SWNT photophysics) is both fundamental and applied. Individual nanotubes may someday be used as superior near-infrared fluorophores, biological tags and sensors, and components for ultrahigh-speed optical communications systems. Establishing an understanding of basic nanotube photophysics is intrinsically significant and should enable the rapid development of such innovations. Unlike conventional molecules, carbon nanotubes are synthesized as heterogeneous samples, composed of molecules with different diameters, chiralities, and lengths. Because a nanotube can be either metallic or semiconducting depending on its particular molecular structure, SWNT samples are also mixtures of conductors and semiconductors. Early progress in understanding the optical characteristics of SWNTs was limited because nanotubes aggregate when synthesized, causing a mixing of the energy states of different nanotube structures. Recently, significant improvements in sample preparation have made it possible to isolate individual nanotubes, enabling many advances in characterizing their optical properties. In this Account, single-molecule confocal microscopy and spectroscopy were implemented to study the fluorescence from individual nanotubes. Single-molecule measurements naturally circumvent the difficulties associated with SWNT sample inhomogeneities. Intrinsic SWNT photoluminescence has a simple narrow Lorentzian line shape and a polarization dependence, as expected for a one-dimensional system. Although the local environment heavily influences the optical transition wavelength and intensity, single nanotubes are exceptionally photostable. In fact, they have the unique characteristic that their single molecule fluorescence intensity remains constant over time; SWNTs do not “blink” or photobleach under ambient conditions. In addition, transient absorption spectroscopy was used to examine the relaxation dynamics of photoexcited nanotubes and to elucidate the nature of the SWNT excited state. For metallic SWNTs, very fast initial recovery times (300–500 fs) corresponded to excited-state relaxation. For semiconducting SWNTs, an additional slower decay component was observed (50–100 ps) that corresponded to electron–hole recombination. As the excitation intensity was increased, multiple electron–hole pairs were generated in the SWNT; however, these e−h pairs annihilated each other completely in under 3 ps. Studying the dynamics of this annihilation process revealed the lifetimes for one, two, and three e−h pairs, which further confirmed that the photoexcitation of SWNTs produces not free electrons but rather one-dimensional bound electron–hole pairs (i.e., excitons). In summary, nanotube photophysics is a rapidly developing area o...

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Section: Electronic Properties and Applicationsmentioning

confidence: 99%

Photophysics of Individual Single-Walled Carbon Nanotubes

2008

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“…Some prototype carbon NEMS have been reported in the literature, [4][5][6][7][8][9][10][11] but there have been relatively few experimental studies of the high frequency properties of carbon NEMS based on individual carbon nanotubes. [12][13][14][15][16] The resonance frequencies of doubly clamped suspended singlewalled nanotubes (SWNT) have been determined using an indirect mixing technique with a lock-in amplifier.…”

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confidence: 99%

Direct Transmission Detection of Tunable Mechanical Resonance in an Individual Carbon Nanofiber Relay

et al. 2008

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Nanoelectromechanical systems (NEMS) are attracting increasing attention due to their small size, low power consumption, and fast switching speeds. 1 They are regarded as among the most interesting emerging technologies on the ITRS roadmap. 2 Carbon nanotubes are particularly interesting as NEMS components due to their low mobile mass and high Young's modulus, which enables high speed, combined with their high mechanical strength and ability to withstand extreme conditions of temperature and radiation exposure. The predicted possibility of tuning the resonance frequency over a large range by the application of a gate voltage 3 is particularly promising for many applications. Here we present a direct transmission measurement of the resonance frequency of an individual singly clamped carbon nanofiber relay. The experimental results verify the predictions of a small signal model and provide important information for determining the practicality of using carbon-based NEMS as components in real electrical circuits.Some prototype carbon NEMS have been reported in the literature, 4-11 but there have been relatively few experimental studies of the high frequency properties of carbon NEMS based on individual carbon nanotubes. [12][13][14][15][16] The resonance frequencies of doubly clamped suspended singlewalled nanotubes (SWNT) have been determined using an indirect mixing technique with a lock-in amplifier. [12][13][14] The method requires a semiconducting nanotube and can therefore not be applied to the mechanically more rigid multiwalled nanotubes (MWNT) or nanofibers (CNF) that have been studied as a dc prototype NEMS and allow the fabrication of more varied device geometries. [4][5][6][7][8]10,11 The mechanical resonances of singly clamped MWNT have been observed in a field emission microscope, where the broadening of the field emission spot was observed as the nanotube was brought into mechanical resonance by the application of an ac voltage on a side gate. The resonance frequency of the MWNT could be tuned by an order of magnitude by increasing the bias voltage on the nanotube and thus increasing the tension. 15 The same technique has recently been used to demonstrate a so-called nanoradio. 16 Although all of these studies provide interesting information concerning the resonance properties of individual carbon nanotubes, they do not provide muchneeded information on the feasibility of integrating carbonbased NEMS in useful electronic circuits nor on the signal levels that can be expected. In this letter, we report the first direct transmission detection of the resonant behavior of a two-terminal carbon nanofiber relay. We compare the experimental data with the predictions of a small signal model, treating the CNF as a simple series resonator. Good agreement is obtained concerning the resonance amplitude, shape, and phase. We show that it is possible to measure the transmission of a single relay device; however, the signal level is very low and most practical applications will need to be based on arrays of such st...

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“…Choosing according to Refs. 7,3 v ≈ 8 · 10 7 cm/sec and a ≈ 20 nm, one finds that characteristic plasmon frequencies lie in far infrared region ω ∼ 10 14 sec −1 , while characteristic wave vectors are estimated as q ∼ 10 6 cm −1 .…”

Section: Introductionmentioning

confidence: 94%

Landau damping in a two-dimensional electron gas with imposed quantum grid

Kuzmenko¹

2004

Nanotechnology

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Dielectric properties of semiconductor substrate with imposed two dimensional (2D) periodic grid of quantum wires or nanotubes (quantum crossbars, QCB) are studied. It is shown that a capacitive contact between QCB and semiconductor substrate does not destroy the Luttinger liquid character of the long wave QCB excitations. However, the dielectric losses of a substrate surface are drastically modified due to diffraction processes on the QCB superlattice. QCB-substrate interaction results in additional Landau damping regions of the substrate plasmons. Their existence, form and the density of losses are strongly sensitive to the QCB lattice constant.

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Carbon Nanotube-Based Nonvolatile Random Access Memory for Molecular Computing

Cited by 1,650 publications

References 25 publications

Photophysics of Individual Single-Walled Carbon Nanotubes

Photophysics of Individual Single-Walled Carbon Nanotubes

Direct Transmission Detection of Tunable Mechanical Resonance in an Individual Carbon Nanofiber Relay

Landau damping in a two-dimensional electron gas with imposed quantum grid

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