Abstract Submitted to the    NANOTUBE'06 Conference:

Carbon Nanotube Electronic and Optoelectronic Devices and Circuits

Phaedon Avouris

IBM Research Division, T.J. Watson Research Center

avouris@us.ibm.com

XIX. Nanotube-Based Transistors

Although a number of different electronic devices based on SW-CNTs have been demonstrated, most of the emphasis has been placed on CNT field-effect transistors (CNTFETs). Such devices have superior characteristics, but also pose a set of new challenges. These include understanding the quasi-1D transport physics, deciphering the different device scaling laws, understanding the barriers at metal-nanotube interfaces, doping them, etc. In my talk I will discuss these issues and demonstrate solutions that allow the fabrication of not only individual devices with excellent characteristics, but also more complex integrated circuits, such as ring oscillators, based on a single CNT molecule. Self-assembly procedures of such devices on high-k dielectrics based on reversible functionalization of the CNTs will also be presented.
Unlike silicon, semiconducting CNTs allow the direct absorption and emission of light. I will discuss the nature of the excited states of CNTs and their production by photon and electron excitation. Radiative recombination of independently injected electrons and holes in an ambipolar CNTFET leads to single nanotube molecule light sources. I will also show that the CNT 1D-character, strong e-h interactions and weak e-phonon interaction allows for efficient intra-molecular impact excitation by hot carriers in CNTs under unipolar conditions. Our theoretical analysis shows that impact excitation rates are many orders of magnitude higher in CNTs compared to 3D solids. Impact neutral exciton production rates are typically twice those of impact ionization and the initial distribution of excitations produced is very different from that produced by photon excitation. Examples of naturally occurring and fabricated structures that emit unipolar electroluminescence will be discussed.

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