Boron-doping effects in carbon nanotubes

Hsu, Wen Kuang; Firth, Steven; Redlich, Ph.; Terrones, Mauricio; Terrones, Humberto; Zhu, Yan; Grobert, Nicole; Schilder, A.; Clark, Robin J. H.; Kroto, Harold W.; Walton, D. R. M.

doi:10.1039/b000720j

Cited by 112 publications

(90 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Three types of multiwalled CNTs were individually incorporated into PS matrix, i.e., a) arc-made CNTs [19], b) arc-made BCNTs [11,20], and c) Fe-filled CNTs made by pyrolysis of ferrocene [21]. The degree of graphitization for arcmade CNTs and BCNTs is similar and the boron concentration in the CNTs is ca.…”

Section: Methodsmentioning

confidence: 99%

High Permittivity from Defective Multiwalled Carbon Nanotubes in the X‐Band

Hsu²,

et al. 2003

View full text Add to dashboard Cite

window size like the one of our new structure. In this sense, the new topology provides the possibility of building full photonic bandgap materials having a very open network of channels, which might improve the functionality of these structures.In conclusion, we report here a new synthetic route to high dielectric contrast photonic crystals based on a colloidal crystal templating approach named micromolding in inverse silica opal (MISO). This method enables silicon colloidal photonic crystals to be obtained that present a new topology, and makes it possible to attain a much wider range of silicon shell thickness relative to inverted silicon colloidal photonic crystals. Theoretical photonic band structure calculations modeling the so-built structure show that a full photonic bandgap is achieved with these distinctive features. This method represents an alternative way to fabricate photonic bandgap materials based on colloidal crystal templating. ExperimentalLatex microspheres with a diameter between~250 nm and~1100 nm were synthesized by polymerization of a commercial styrene stabilized with 10± 15 ppm of 4-tert-butylcatechol (Aldrich, 99 vol.-%). After removing the stabilizer by treating with NaOH, the polymerization was initiated by thermal decomposition of potassium persulfate at 70 C. In order to form the starting latex opals, microspheres were dispersed in ethanol and centrifuged for several hours as the ethanol was evaporating. Centrifuge tube holders could be tilted up to 90 in order to obtain parallel top and bottom surfaces in the sediment. The brightly iridescent latex opals thus formed were broken into several pieces in order to remove them from the test tubes. These colloidal crystals were placed in a Buchner funnel and several drops of silica precursor were placed on the top of the pellets with a pipette while vacuum was applied for a couple of minutes, following the method described in [14]. Alternatively, the crystals were placed in a small vial containing the precursor solution and the vial was evacuated until air bubbles arising from the infiltration of the voids inside the opal could not be observed any more. The crystals were dried for several hours at room temperature and subsequently thermally treated in air at 580 C to remove the latex template and obtain the desired silica inverted opal. Amorphous silicon was infiltrated using disilane CVD (Si 2 H 6 , 99.99 % Aldrich), using the same experimental set up and following similar recipes to those employed by Blanco et al. [5]. Removal of the silica template was done by soaking the silicon infiltrated confined colloidal crystal arrays in a 1 wt.-% HF aqueous etching solution. Every step in the synthetic route by MISO towards the final silicon colloidal photonic crystal was monitored by employing a field-emission SEM (Hitachi S-4500). High Permittivity from Defective Multiwalled Carbon Nanotubes in the X-Band** By Paul C. P. Watts, Wen-Kuang Hsu,* Alan Barnes, and Barry ChambersRadar adsorbing materials (RAMs) have become increasingly important, n...

show abstract

Section: Methodsmentioning

confidence: 99%

High Permittivity from Defective Multiwalled Carbon Nanotubes in the X‐Band

Hsu²,

et al. 2003

View full text Add to dashboard Cite

show abstract

“…[3,4] A tiny bundle of BCNTs was carefully extracted from protruding nanotube aggregates (Figure 1 a) via a micromanipulatorcontrolled tungsten tip (Figure 1 b). The bundles consisted of about 2-4 tubules.…”

Section: Methodsmentioning

confidence: 99%

Weak Backscattering in Deflected Doped Carbon Nanotubes

Hsu

2005

ChemPhysChem

View full text Add to dashboard Cite

“…2a). In fact, the excess of hexagons (or W and S atoms) is essential in a defect-free multi-walled nanotube, because a constant layer separation along the caxis can only be maintained when the number of hexagons in each shell is not identical [15]. The excess of atoms can be accommodated either by extending the layer into a tube cap [16] or by interweaving, i.e., interfacial dislocation [17].…”

Section: Resultsmentioning

confidence: 99%