| Carbon nanotubes have received much attention in recent years due to their high structural stability and interesting electronic and transport properties. These novel properties can be utilized in many areas of applications. Many of these applications require modifications to pristine nanotubes. In particular, chemical functionalizations have been shown to be an attractive method to tailor some of electronic and mechanical properties. In this study, I present our computational study on electronic and transport properties of covalently side-wall functionalized carbon nanotubes. We found that functional-group-induced impurity states play important roles in modifying electronic and transport properties of nanotube near the Fermi level. A drastic difference has been found between monovalent and divalent functionalization cases. In monovalent functionalizations, the impurity states are located near the Fermi level and have strong effects on both electronic and transport properties. On the other hand, divalent functionalizations do not cause any significant disruption near the Fermi level due to rehybridization of two adjacent impurity states into bonding and antibonding states located relatively far away from the Fermi level. We believe that the covalent functionalization induced property changes provide a pathway for the band structure engineering, electronic, and chemical sensor applications of carbon nanotubes. |
