In this talk, I will present efforts to understand electrical/mechanical properties of carbon nanotubes (CNTs) by combining electric transport measurements and the scanning probe microscopy.
In the first set of experiments, a metallized AFM tip in electrical contact with CNT is utilized as a local voltage or current probe. For semiconducting CNT field effect transistors, these measurements reveal the nature of contacts between semiconducting CNTs and the metal electrodes. In metallic CNTs, the electron scattering rates are studied from the scaling of the device characteristics in the same CNT with length.
In another set of experiments, an AFM is used to modify electrical/mechanical properties of CNT devices. By applying voltage pulses from an AFM tip, the electrical properties of CNT device can be permanently modified. The possibility of custom-engineered CNT device using this technique will be demonstrated and discussed. On the other hand, an AFM tip has been used to simultaneously vary strain on the CNT and to electrostatically gate the tube. The results show that the band structure of a CNT can be drastically altered by mechanical strains.
PHYS 242, Purdue University, West Lafayette, IN