Studies of Mechanically Deformed Single Wall Carbon Nanotubes and Graphene by Optical Spectroscopy

Due to the extremely low density of defects, carbon nanotubes and graphene were predicted in theory and demonstrated experimentally to possess excellent mechanical properties and can sustain relatively large strain. This gives us an opportunity to explore the impact of mechanical deformation to their physical properties. In the first half of the thesis, we present the studies about mechanical and electromechanical properties of the optical characterized single wall carbon nanotubes (SWNTs). For the mechanical properties, we have combined optical spectroscopy with a magnetic actuation technique to measure the stiffness of these structure defined SWNTs. The measured stiffnesses correspond to an average Young’s modulus of E = 0.99 TPa. By using the same devices, the non-linear resonators were demonstrated and their behaviors can be understood from the damped Duffing resonator model. In addition, the breaking strength of the SWNTs was measured by mechanical tensile testing. The resulting fracture strength is about 40 GPa and which corresponds to 3.6 % failure strain. This value can be regarded as the low bound of the breaking strength due to the clamping induced extra defects. For the electromechanical property, the effect of uniaxial strain o