Raman Spectroscopy and Molecular Dynamics Simulation Studies of Carbon Nanotubes

Carbon Nanotubes (CNTs) are honey-combed lattices rolled up into cylinders with nanometer-sized diameters and lengths on the order of microns. Actively studied for over thirty years, and with now greater availability, single-walled nanotubes are predicted to significantly impact semi-conductor physics, owing to their unique electronic properties and reduced dimensionality. Some of the semi-conductor technologies in which CNTs are expected to hold significant promise are in super-capacitors, hydrogen storage materials, nanoprobes, and bio-chemical sensors. Necessary to many future CNT applications is a clear understanding of their thermal properties, as nano-devices based on single-walled and/or multi-walled nanotubes may have to experience high temperatures during the manufacturing process while being operated. This, in turn, affects the reliability due to thermal expansion and the ensuing strain in the electronic devices. The coefficient of thermal expansion (CTE) of CNTs is a key property for nano-electronic applications. In this paper we will present Raman Spectroscopy measurements of single-walled carbon nanotubes as a function of temperature in the range 25-200 degrees C, as well as Molecular Dynamics (MD) simulations that incorporate current state-ofthe-art models of Carbon-Carbon interactions associated with the thermal expansion of carbon nanotubes.