The metallic nanoparticles of Ni and Co were characterized using transmission electron microscopy (TEM) and atomic-force microscopy (AFM). The catalytic nanoparticles were obtained by modified method of reverse micelles of bis-(2-ethylhexyl) sulfosuccinate sodium in isooctane solution that provides the nanoparticle size control in range of 1 to 5 nm. We report on a method of synthesis of single-walled carbon nanotubes percolated networks on silicon dioxide substrates using monodisperse Co and Ni catalyst. More importantly, we show that this process preserves the quality of the resulting purified nanotubes. We show that the developed process combines selective elimination of catalytic impurities and high yields. The purified samples have been characterized by transmission electron microscopy, thermogravimetric analysis, magnetic measurements and Raman spectroscopy. These thermodynamic conditions favor high chlorine diffusion to metal impurities embedded in carbon shells thus inducing an avalanche process of metal chloride formation and sublimation. The proposed process merely consists of heating up SWNT powder under high chlorine partial pressure and high temperature. Here, we propose an alternative process that allows preparing high-quality and high-purity SWNT samples. The commonly used purification procedures are based on multi-step treatments that are often too aggressive towards the CNTs, leading to disappointing yields.
The presence of structural defects and metallic particles in pristine single walled carbon nanotubes (SWNTs) is responsible for the alteration of both their chemical stability and their magnetic and electrical properties. Large scale production of high quality CNT samples is still challenging. Superconducting proximity effect for CNTFETs with superconduting Will also discuss carbon nanotubes used as nanoscale probes for Temperature transport phenomena of these devices, including quantizedĬonductance, coherent interference, and single electron tunneling. Moreover, I have measured the general low
Reported for intrinsic superconductivity in carbon nanotubes (rangingįrom 0.5 K to 15 K). To 30 K, which is higher than the critical temperatures previously The carbon nanotube In our devices, we measured critical temperatures up Reflection occurring at the CNT/Pd interfaces when Cooper pairs form in Of conductance at low temperature is then attributed to Andreev
Singularities of its density of states by a gate voltage. When the Fermi level of the carbon nanotube is shifted into van Hove That this is due to intrinsic superconductivity in the carbon nanotube Increases with decreasing temperature below a critical value. Special gate voltage ranges, the conductance of carbon nanotube
Superconductivity in carbon nanotubes, I fabricated low-resistanceĬNTFETs with contacts made of palladium, a normal metal. Different metals (superconductingĪnd normal metal) have been deposited to make source and drain contacts Substrate covered by a layer of thermally grown silicon oxide, so that Synthesized by chemical vapor deposition (CVD) on heavily doped silicon (CNTFETs) made of individual carbon nanotubes. Measurements are carried out on carbon nanotube field-effect transistors For my thesis, I conducted experiments to investigate superconductivityĪnd superconducting proximity effect in carbon nanotubes.
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