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Electronic Properties of Carbon Nanotubes and JunctionsMetallic and semiconducting Single Wall Carbon Nanotubes (CNT) have recently been characterized using scanning tunneling microscopy (STM) and the manipulation of individual CNT has been demonstrated. These developments make the prospect of using CNT as molecular wires and possibly as electronic devices an even more interesting one. We have been modeling various electronic properties such as the density of states and the transmission coefficient of CNT wires and junctions. These studies involve first calculating the stability of junctions using molecular dynamics simulations and then calculating the electronic properties using a pi-electron tight binding Hamiltonian. We have developed the expertise to calculate the electronic properties of both finite-sized CNT and CNT systems with semi-infinite boundary conditions. In this poster, we will present an overview of some of our results. The electronic application of CNT that is most promising at this time is their use as molecular wires. The conductance can however be greatly reduced because of reflection due to defects and contacts. We have modeled the transmission through CNT in the presence of two types of defects: weak uniform disorder and strong isolated scatterers. We find that the conductance is affected in significantly different manners due to these defects Junctions of CNT have also been imaged using STM. This makes it essential to derive rules for the formation of junctions between tubes of different chirality, study their relative energies and electronic properties. We have generalized the rules for connecting two different CNT and have calculated the transmission and density of states through CNT junctions. Metallic and semiconducting CNT can be joined to form a stable junction and their current versus voltage characteristics are asymmetric. CNT are deformed by the application of external forces including interactions with a substrate or other CNT. In many experiments, these deformation are expected to occur naturally. We will present some preliminary results of our calculations of the modification of CNT electronic properties as a result of deformations.
Document ID
20020061370
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Anantram, M. P.
(NASA Ames Research Center Moffett Field, CA United States)
Han, Jie
(NASA Ames Research Center Moffett Field, CA United States)
Yang, Liu
(NASA Ames Research Center Moffett Field, CA United States)
Govindan, T. R.
(NASA Ames Research Center Moffett Field, CA United States)
Jaffe, R.
(NASA Ames Research Center Moffett Field, CA United States)
Saini, Subhash
Date Acquired
August 20, 2013
Publication Date
January 1, 1998
Subject Category
Solid-State Physics
Meeting Information
Meeting: Gigascale Integration Technology Symposium
Location: Pullman, WA
Country: United States
Start Date: September 27, 1998
End Date: September 30, 1998
Sponsors: Society of Engineering Science
Funding Number(s)
CONTRACT_GRANT: NAS2-14303
PROJECT: RTOP 519-40-12
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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