Applications of multi-walled carbon nanotube in electronic packaging

Thermal management of integrated circuit chip is an increasing important challenge faced today. Heat dissipation of the chip is generally achieved through the die attach material and solders. With the temperature gradients in these materials, high thermo-mechanical stress will be developed in them, and thus they must also be mechanically strong so as to provide a good mechanical support to the chip. The use of multi-walled carbon nanotube to enhance the thermal conductivity, and the mechanical strength of die attach epoxy and Pb-free solder is demonstrated in this work

Relation between metal electronic structure and morphology of metal compounds inside carbon nanotubes

International audienceSEVERAL attempts have been made to fill carbon nanotubes(1) with metals or metallic compounds to obtain nanocomposite materials with potentially interesting properties. Capillary action, predicted(2) to be a filling mechanism, has been used(3,4) to encapsulate lead and bismuth in open tubes. Compounds of yttrium(5), manganese(6) and gadolinium(7) have also been encapsulated by formation of the nanotubes in an are discharge with the metals present in situ. Very recently, Tsang et al.(8) showed that oxides of nickel, cobalt, iron and uranium can be encapsulated by opening the tubes and depositing the filling material using wet chemical techniques. Here we report a search for general principles relating to the nature and structure of the filling material, using the are-discharge method to fill tubes with fifteen metals and/or their compounds: Ti, Cr, Fe, Co, Ni, Cu, Zn, Mo, Pd, Sn, Ta, W, Gd, Dy and Yb. We find that the propensity for forming continuous 'nanowires' throughout the length of the tubes seems to be strongly correlated with the existence of an incomplete electronic shell in the most stable ionic state of the metal. We also find that the interplay between growth of the nanotube and growth of the filling results, in one case, in the formation of an unusual helical filling morphology

Optical-phonon behavior in Ga1-xInxAs: The role of microscopic strains and ionic plasmon coupling

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Electrical properties of boron-doped diamond-like carbon thin films deposited by femtosecond pulsed laser ablation

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Formation of Ordered Ice Nanotubes Inside Carbon Nanotubes

Following their discovery, carbon nanotubes have attracted interest not only for their unusual electrical and me-chanical properties, but also because their hollow interior can serve as a nanometre-sized capillary, mould, or template in material fabrication. The ability to en¬capsulate a material in a nanotube also offers new possibili¬ties for investigating dimensionally confined phase transi¬tions . Particularly intriguing is the conjecture that matter within the narrow confines of a carbon nanotube might ex¬hibit a solid–liquid critical point beyond which the distinc¬tion between solid and liquid phases disappears. This unusual feature, which cannot occur in bulk material, would allow for the direct and continuous transformation of liquid matter into a solid. Here we report simulations of the behavior of water encapsulated in carbon nanotubes that suggest the existence of a variety of new ice phases not seen in bulk ice, and of a solid–liquid critical point. Using carbon nanotubes with diameters ranging from 1.1 nm to 1.4 nm and applied axial pressures of 50 MPa to 500 MPa, we find that water can exhibit a first-or¬der freezing transition to hexagonal and heptagonal ice nano¬tubes, and a continuous phase transformation into solid-like square or pentagonal ice nanotubes