Schottky barrier formation at a carbon nanotube—metal junction

The issue of Schottky barrier formation at carbon nanotube (CNT) contacts with metal leads is of crucial importance for nanotube-based electronic devices. The authors examine the electronic properties of a particular structure containing a metal/CNT contact that resembles experimental setups for CNT field-effect transistors. The model consists of a single-wall (8,0) CNT with its central section fully covered by a Pd ring, representing the metal electrode. Through first-principles total energy and electronic structure calculations within density functional theory, the authors establish that the junction between the metal-covered part and the bare part of the CNT is responsible for the experimentally measured Schottky barrier of ∼0.4eV in CNT field-effect transistors.