Electrical evidence for the encapsulation of C-60 inside a carbon nanotube: Random telegraph signal and hysteric current-voltage characteristics

Abstract

We present electrical evidence for the encapsulation of C-60's inside a carbon nanotube, random telegraph signals (RTSs), and hysteric current-voltage characteristics. RTSs are shown only at voltages higher than a critical voltage. We suggest that the origin of the RTSs is ascribed to the instability of the quantum harmonic oscillations of C-60's. RTSs are smeared out at a temperature which is well correlated with the energy level of the vibrational quantum mediated by the van der Waals binding between the carbon nanotube and C-60's. In addition, hysteric behavior in cyclic current-voltage characteristics is explained by the longitudinal motion and resettlement of the C-60's with the modulation of the size of the quantum dot mediated by the C-60 insertion.