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We investigate theoretically the switching characteristics of semiconducting carbon nanotubes connected to gold electrodes under an external (gate) electric field. We find that the external introduction of holes is necessary to account for the experimental observations. We identify metal-induced-gap states (MIGS) at the contacts and find that the MIGS of an undoped tube would not significantly affect the switching behavior, even for very short tube lengths. We also explore the miniaturization limits of nanotube transistors, and, on the basis of their switching ratio, we conclude that transistors with channels as short as 50AA would have adequate switching characteristics.
We have used a femtosecond pump-probe impulsive Raman technique to explore the polarization dependence of coherent optical phonons in highly-purified and aligned semiconducting single-wall carbon nanotubes (SWCNTs). Coherent phonon spectra for the ra
Ultrafast terahertz spectroscopy accesses the {em dark} excitonic ground state in resonantly-excited (6,5) SWNTs via internal, direct dipole-allowed transitions between lowest lying dark-bright pair state $sim$6 meV. An analytical model reproduces th
Since it is undesirable to require an external magnetic field for on-chip memory applications, we investigate the use of a Rashba effective field alternatively for assisting the electric-field-induced switching operation of a three terminal perpendic
Through ultrafast pump-probe spectroscopy with intense pump pulses and a wide continuum probe, we show that interband exciton peaks in single-walled carbon nanotubes (SWNTs) are extremely stable under high laser excitations. Estimates of the initial
We study the binding energies and optical properties of direct and indirect excitons in monolayers and double layer heterostructures of Xenes: silicene, germanene, and stanene. It is demonstrated that an external electric field can be used to tune th