Field emission of different oriented carbon nanotubes

Chen, Yan; Shaw, D.T.; Guo, Liping

doi:10.1063/1.126379

Cited by 253 publications

(100 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, experimental works have been made to investigate the sidewall field emission properties of CNTs aligned in bundle [16], [17]. Two conclusions were drawn in these works: the sidewall field emission obeys the Fowler-Nordheim equation [16], [17], and field emission performance increases with decreasing bundle diameter [17]. This property suggests that the best emission performance is from the body (the side wall) of individual CNTs.…”

Section: F Theory Of Carbon Nanotube Emissionsmentioning

confidence: 91%

“…Many theoretical works have been published related to the field emission at the tip of individual capped CNTs, based both on the density functional theory or the Green's function theory [12], [13], or even using the symmetry properties of CNTs for solving the Schroedinger equation [14], [15]. On the other hand, experimental works have been made to investigate the sidewall field emission properties of CNTs aligned in bundle [16], [17]. Two conclusions were drawn in these works: the sidewall field emission obeys the Fowler-Nordheim equation [16], [17], and field emission performance increases with decreasing bundle diameter [17].…”

Section: F Theory Of Carbon Nanotube Emissionsmentioning

confidence: 99%

See 1 more Smart Citation

Highly Sensitive Carbon Nanotube-Based Sensing for Lactate and Glucose Monitoring in Cell Culture

Boero

Carrara

Vecchio

et al. 2011

IEEE Trans.on Nanobioscience

View full text Add to dashboard Cite

Abstract-Monitoring of metabolic compounds in cell cultures can provide real-time information of cell line status. This is particularly important in those lines not fully known, as the case of embryonic and mesenchymal cells. On the other hand, such approach can pave the way to fully automated systems for growing cell cultures, when integrated in Petri dishes. To date, the main efforts emphasize the monitoring of few process variables, like pH, pO , electronic impedance, and temperature in bioreactors. Among different presented strategies to develop biosensors, carbon nanotubes exhibit great properties, particularly suitable for high-sensitive detection. In this work, nanostructured electrodes by using multiwalled carbon nanotubes are presented for the detection of lactate and glucose. Some results from simulations are illustrated in order to foresee the behavior of carbon nanotubes depending on their orientation, when they are randomly dispersed onto the electrode surface. A comparison between nonnanostructured and nanostructured electrodes is considered, showing that direct electron-transfer between the protein and the electrode is not possible without nanostructuration. Such developed biosensors are characterized in terms of sensitivity and detection limit, and are compared to previously published results. Lactate production is monitored in a cell culture by using the developed biosensor, and glucose detection is also performed to validate lactate behavior.

show abstract

Section: F Theory Of Carbon Nanotube Emissionsmentioning

confidence: 91%

Section: F Theory Of Carbon Nanotube Emissionsmentioning

confidence: 99%

Highly Sensitive Carbon Nanotube-Based Sensing for Lactate and Glucose Monitoring in Cell Culture

Boero

Carrara

Vecchio

et al. 2011

IEEE Trans.on Nanobioscience

View full text Add to dashboard Cite

show abstract

“…2, many of the nanotubes near the top of the aperture had a significant horizontal component ͑parallel to the top surface͒ and pointed toward the center part of the gate aperture. The side portions of the nanotubes might also contribute to emission by emitting from defects sites, according to observations of Chen and Shaw, 21 on field emission dependence on nanotube orientation. Emission characterization was carried out in an ultra high vaccum chamber ͑base pressure 10 Ϫ10 Torr͒ equipped with cathode, gate, and anode probes with computerized data collection for current-voltage, current-time, and electron energy distribution characteristics.…”

mentioning

confidence: 99%

Microgating carbon nanotube field emitters by in situ growth inside open aperture arrays

Hsu

2002

Applied Physics Letters

View full text Add to dashboard Cite

Multiwalled carbon nanotubes were grown using chemical vapor deposition inside small apertures having a horizontal gate and a sidewall insulator spacer. Emission currents up to 140 nA per cell at 63 V have been obtained. These arrays have exhibited a gate current as low as 2.5% of the anode current throughout the entire gate voltage range, representing the lowest gate to anode current ratio of gated nanotube emitters reported to date. We attribute this feature to the emitter geometry and method of fabrication. The overall fabrication method required only a few and simple processing steps. ͓DOI: 10.1063/1.1472463͔One of the first applications of carbon nanotubes ͑cNTs͒ has been their use as field emitters on account of their natural material, structural, and electronic properties which satisfy many demanding requirements for field emission, including stability, robustness, low voltage, high current-carrying capacity, and mechanical strength. A key factor to their stability as field emitters is the lack of a nonvolatile surface oxide. Surface oxide formation ͑such as on metal or silicon emitters͒ increases the work function, impedes electron transport, and makes the effective work function variable during emission. Furthermore, surface oxides could be the main cause for field emitter array ͑FEA͒ catastrophic destruction by trapping charge which could lead to arcing.1 Carbon nanotubes are also less likely to form nanoprotrusions as metal and silicon cathodes do, thus reducing the probability of current runaway.2 Their small diameters ͑2-50 nm͒ and high aspect ratios enable the high electric field enhancement for lowvoltage operation, despite the relatively high work function (ϳ5.0 eV for graphite͒. They are resistant to blunting by residual back ion bombardment, especially when placed vertical to the substrate, since the nanotube diameter remains the same even when material has been removed from by sputtering.The most commonly studied cNT emitters involved a diode configuration in which the cNTs, grown or placed as dense mats on substrates, were positioned at a known separation from an anode, to which a positive potential was applied to induce field emission from the cNTs. Although very low turn-on voltages ͑as low as 1-2 V per m͒ were measured, the voltages used were still too high for most applications because the cNT-anode separations were usually large distances. In addition, many device applications, such as flat panel displays, require precise control of the array pixels, thus precluding a diode configuration. Hence, gating of the emission by the placement of a third electrode in close and precise proximity to a group of cNT emitters is necessary to lower the operating voltage as well as afford precise local control of emission. Gating is necessary to enable certain applications which include field emitter displays, highfrequency amplifiers, high-voltage switches, portable x-ray sources, multibeam electron-beam lithography, radiation and temperature-insensitive electronics, space craft propulsion, and electro...

show abstract

“…They are used to enhance the emissivity of electrodes made of various materials [4]. Many theoretical [5,6] and experimental [7] works have been published related to CNT field. The results suggest that the major contribution to emission performance is mainly from the body (the sidewall) of each individual CNT.…”

Section: Introductionmentioning

confidence: 99%

Targeting of multiple metabolites in neural cells monitored by using protein-based carbon nanotubes

Boero

Carrara

Vecchio

et al. 2011

Sensors and Actuators B: Chemical

View full text Add to dashboard Cite

a b s t r a c tMicrodevices dedicated to monitor metabolite levels have recently enabled many applications in the field of cell analysis, to monitor cell growth and development of numerous cell lines. By combining the traditional technology used for electrochemical biosensors with nanoscale materials, it is possible to develop miniaturized metabolite biosensors with unique properties of sensitivity and detection limit. In particular, enzymes tend to adsorb onto carbon nanotubes and their optical or electrical activity can perturb the electronic properties. In the present work we propose multi-walled carbon nanotube-based biosensors to monitor a cell line highly sensitive to metabolic alterations, in order to evaluate lactate production and glucose uptake during different cell states. We achieve sensors for both lactate and glucose, with sensitivities of 40.1 A mM −1 cm −2 and 27.7 A mM −1 cm −2 , and detection limits of 28 M and 73 M, respectively. This nano-biosensing technology is used to provide new information on cell line metabolism during proliferation and differentiation, which are unprecedented in cell biology.

show abstract

Field emission of different oriented carbon nanotubes

Cited by 253 publications

References 15 publications

Highly Sensitive Carbon Nanotube-Based Sensing for Lactate and Glucose Monitoring in Cell Culture

Highly Sensitive Carbon Nanotube-Based Sensing for Lactate and Glucose Monitoring in Cell Culture

Microgating carbon nanotube field emitters by in situ growth inside open aperture arrays

Targeting of multiple metabolites in neural cells monitored by using protein-based carbon nanotubes

Contact Info

Product

Resources

About