Cs doping effects on electronic structure of thin nanotubes

Using ab initio density functional simulations, we investigate the localization of energy states and the changes of the electronic structures in pristine and Cs-doped cap and stem (5, 5) nanotubes. Although the pristine capped structure has a semiconducting character, the doped capped structures are metallic. For the (5,5) stem, the dangling bonds created as a result of Cs collisions result in generation of extra states within the pseudogap, such that the density of states at Fermi energy is increased. The localization of the states near the Fermi energy at the cap, and the reduction of the work functions of Cs-doped capped structures make them suitable for field emission. (c) 2005 Elsevier B.V. All rights reserved.