scispace - formally typeset
Search or ask a question
Author

Luxi Qian

Bio: Luxi Qian is an academic researcher from Central University, India. The author has contributed to research in topics: Carbon nanotube & Mechanical properties of carbon nanotubes. The author has an hindex of 7, co-authored 8 publications receiving 2213 citations.

Papers
More filters
Journal ArticleDOI
06 Dec 1996-Science
TL;DR: Large-scale synthesis of aligned carbon nanotubes was achieved by using a method based on chemical vapor deposition catalyzed by iron nanoparticles embedded in mesoporous silica to form an aligned array of isolated tubes with spacings between the tubes.
Abstract: Large-scale synthesis of aligned carbon nanotubes was achieved by using a method based on chemical vapor deposition catalyzed by iron nanoparticles embedded in mesoporous silica. Scanning electron microscope images show that the nanotubes are approximately perpendicular to the surface of the silica and form an aligned array of isolated tubes with spacings between the tubes of about 100 nanometers. The tubes are up to about 50 micrometers long and well graphitized. The growth direction of the nanotubes may be controlled by the pores from which the nanotubes grow.

1,772 citations

Journal ArticleDOI
13 Aug 1998-Nature
TL;DR: In this article, pyrolysis of acetylene over iron/silica substrates is an effective method with which to produce very long, multiwalled carbon nanotubes that reach about 2 mm in length.
Abstract: Carbon nanotubes1 can now be produced in large quantities by either arc methods2,3 or thermal decomposition of hydrocarbons4,5. Here we report that pyrolysis of acetylene over iron/silica substrates is an effective method with which to produce very long, multiwalled carbon nanotubes that reach about 2 mm in length, which is an order of magnitude longer than that described in most previous reports1,2,3,4,5,.

341 citations

Journal ArticleDOI
TL;DR: In this article, the improved chemical vapor deposition (CVD) method was used to grow high ordered, isolated, long carbon nanotubes over large areas using the improved CVD method reported here.
Abstract: Highly ordered, isolated, long carbon nanotubes can be grown over large areas using the improved chemical vapor deposition (CVD) method reported here. The secret to the controlled growth lies in the substrate used-mesoporous silica embedded with iron nanoparticles. After synthesis, the substrate can be removed, retaining aligned tubes with neat roots. The production of pure, homogeneous, and uniform samples of highly graphitized nanotubes is important not only for potential applications but also for detailed characterization of the nanotubes' properties.

50 citations

Journal ArticleDOI
TL;DR: In this article, optical transmission spectroscopy and photothermal deflection spectra were used to determine the spectra of C70 thin films over a wide energy range (0.6-6.5 eV).
Abstract: Both optical transmission spectroscopy and photothermal deflection spectroscopy are used to determine the spectra of C70 thin films over a wide energy range (0.6–6.5 eV). Based on a molecular orbital model, the optical transitions for the C70 thin film are analyzed. The weak absorption spectra of C70 thin films are similar to that of an amorphous semiconductor. The optical energy gap is derived by a Tauc plot as 1.66 eV. The gap region can be described in terms used for amorphous semiconductors, having features such as an Urbach edge and subgap defect absorption, which are interpreted as a broadening due to disorder or impurities. The effects of the deflection medium on the weak absorption spectra of C70 films are discussed.

38 citations

Journal ArticleDOI
TL;DR: In this paper, the growth of carbon nanotubes from catalytic thermal decomposition of acetylene on fine iron particles has been studied and two new kinds of carbon nano-tubes have been found.
Abstract: The growth of carbon nanotubes from catalytic thermal decomposition of acetylene on fine iron particles has been studied. Electron microscopic images of the carbon nanotubes “as formed” and after annealing treatment are presented. Besides the ordinary carbon nanotubes which have been reported (S. Iijima, Nature, 354 (1991) 56), we have found, at first time, two other new kinds of carbon nanotubes: one is straight or curved nanotube with many irregular multi-layered diaphragms in the hollow core, in particular, the fringes of the wall of the tubes are not parallel to the axis of the tube; another one has many regular diaphragms (bamboo-like) which keep almost constant distance with each other. A model that postulates two steps growth of nanotubes from catalyst particles is proposed to explain the microstructure of the novel carbon nanotubes.

22 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: A review of recent advances in carbon nanotubes and their composites can be found in this article, where the authors examine the research work reported in the literature on the structure and processing of carbon Nanotubes.

4,709 citations

Journal ArticleDOI
22 Jan 1999-Science
TL;DR: The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported and the mechanisms of nanotube growth and self-orientation are elucidated.
Abstract: The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-assembly for orientation. The mechanisms of nanotube growth and self-orientation are elucidated. The well-ordered nanotubes can be used as electron field emission arrays. Scaling up of the synthesis process should be entirely compatible with the existing semiconductor processes, and should allow the development of nanotube devices integrated into silicon technology.

3,093 citations

Journal ArticleDOI

3,052 citations

Journal ArticleDOI
TL;DR: An unusually high value, lambda approximately 6600 W/m K, is suggested for an isolated (10,10) nanotube at room temperature, comparable to the thermal conductivity of a hypothetical isolated graphene monolayer or diamond.
Abstract: Recently discovered carbon nanotubes have exhibited many unique material properties including very high thermal conductivity. Strong sp 2 bonding configurations in carbon network and nearly perfect self-supporting atomic structure in nanotubes give unusually high phonon-dominated thermal conductivity along the tube axis, possibly even surpassing that of other carbon-based materials such as diamond and graphite (in plane). In this chapter, we explore theoretical and experimental investigations for the thermal-transport properties of these materials.

3,011 citations

Journal ArticleDOI
Ryong Ryoo1, Sang Hoon Joo1, Shinae Jun1
TL;DR: Ordered carbon molecular sieves exhibiting Bragg diffraction of X-ray lines have been synthesized for the first time, using mesoporous silica sieves as the template.
Abstract: Ordered carbon molecular sieves exhibiting Bragg diffraction of X-ray lines have been synthesized for the first time, using mesoporous silica molecular sieves as the template. Sucrose was converted to carbon inside the mesopores of the silica molecular sieves through a mild carbonization process using a sulfuric acid catalyst. The carbon molecular sieves were obtained after the removal of the silica framework using an aqueous solution of sodium hydroxide. The X-ray diffraction, transmission electron microscopy, and pore size analysis showed that the structure of the carbon molecular sieves consisted of a three-dimensional regular array of uniform mesopores 3 nm in diameter. The structure was not simply a negative replica of the used silica template, but the synthesis mechanism involved the unique transformation into a new ordered array that was triggered by the removal of the silica frameworks. The highly ordered mesoporous texture suggested its scientific and technological importance as a new shape-selec...

2,298 citations