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Full-Text Articles in Nanoscience and Nanotechnology

Synthesis And Spectroscopic Characterization Of Nanostructured Thermoelectric Materials, Jason Reppert Dec 2009

Synthesis And Spectroscopic Characterization Of Nanostructured Thermoelectric Materials, Jason Reppert

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Bismuth in the bulk form is a semimetal with a rhombohedral structure. It has a small band overlap between the conduction and valence bands and a highly anisotropic electron effective-mass tensor. Thermoelectric materials, in which one of the three dimensions is in the nanometer regime, exhibit unique quantum confinement properties and have generated much interest in recent years. Theoretical investigations have suggested that nanowires with diameters ≤ 10 nm will possess a figure-of-merit ZT > 2. Prior to this study, it has been shown that Bi nanowires with small enough diameters (~10 nm), prepared via the pulsed laser vaporization method, undergo a ...


Inter-Tube Bonding And Defects In Carbon Nanotubes And The Impact On The Transport Properties And Micro-Morphology, Keqin Yang Dec 2009

Inter-Tube Bonding And Defects In Carbon Nanotubes And The Impact On The Transport Properties And Micro-Morphology, Keqin Yang

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The transport properties of the carbon nanotubes (CNTs) are affected by the tube-tube interaction and the defects presented in the system. Inter-tube bonding, formed during spark plasma sintering (SPS) process, lowers the electrical/thermal resistivity at the tube-tube junctions and also causes new scattering mechanisms such as strong electron-phonon coupling (EPC) at low temperature. More evidences have been found by changing the SPS temperature and doping the CNTs to support the electron-phonon coupling is Kohn anomaly (KA) in as-SPSed CNTs. The phonon drag, appearing in thermoelectric power (TEP) of the as-SPSed CNTs at low temperature, can be explained in the ...