Berlin 2001 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 1: Special Symposium: Molecular Dynamics in Confined Geometries

CPP 1.1: Hauptvortrag

Montag, 2. April 2001, 10:30–11:15, 3010

Carbon Nanotubes: Electrical Properties and Devices — •Phaedon Avouris — IBM Research Division, T. J. Watson Research Center, Yorktown Heights, NY 10598, USA

Carbon nanotubes (NTs) are nanostructures with unique mechanical and electrical properties.Depending on their structure they can be metals or semiconductors. NTs are of great interest in science as ideal models on which to study the physics of 1D systems, and in technology as prime candidates for a future nanoelectronics technology based on carbon instead of silicon.I will first discuss the electronic structure of single wall nanotubes (SWNTs)and show that metallic SWNTs are excellent metals able to carry current densities 2-3 orders of magnitude higher than those of conventional metals. Up to now, all semiconducting SWNTs studied have shown p-type behavior. I will demonstrate schemes by which n-type and intrinsic nanotubes can be produced.Individual semiconducting SWNTs can be used as channels of field-effect transistors (FETs) to produce fully functional devices. The characteristics of these transistors will be compared with those made of silicon. Furthermore, FETs can be fabricated using SWNT bundles containing both metallic and semiconducting nanotubes through a process that sidesteps the need of selective synthesis.I will then discuss the structure and properties of multi-walled nanotubes (MWNTs). I will describe a process by which these tubes can be taken apart shell-by-shell allowing the electronic properties of each shell to be determined. This process allows the fabrication of devices with variable band-gap.