Effects of topological defects in the semiconductor carbon nanotube intramolecular junctions
National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P.R. China
2 Department of Applied Physics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P.R. China
Corresponding author: a email@example.com
Published online: 9 April 2004
Several intramolecular junctions (IMJs) connecting two semiconductor single-wall carbon nanotubes (SWNTs) have been realized by using the layer-divided technique and introducing the pentagon-heptagon topological defects. The atomic structure of each IMJ is optimized with a combination of density-functional theory (DFT) and the universal force field (UFF) method, based upon which a -orbital tight-binding calculation is performed on its electronic properties. Obtained results indicate that different topological defects and their distributions on the interfaces of the IMJs have decisive effects on the electronic properties of the IMJs. The specific geometrical defects control the localized defect states chiefly, while the diameters of the SWNTs on both sides are also related to them. The influence on the experimental observation brought by the choice of the scanning line is also presented by comparing the scanning results performed on the defect side with those on the defect-free side. A new IMJ structure has been found, and it probably reflects the real atomic structures of the semiconductor-semiconductor (S-S) IMJ [Phys. Rev. Lett. 90, 216107 (2003)].
PACS: 61.46.+w – Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals / 73.20.At – Surface states, band structure, electron density of states / 73.40.Lq – Other semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004