Novel structures and materials, such as ultra-scaled Si MOSFETs, multiple gate
MOSFETs, carbon nanotube FETs, and molecular-based transistors, are expected to be
introduced to meet the requirements for scaling. A deep
understanding of quantum effects in nanoelectronic devices helps to improve
the functionality of devices and to develop new device types. For this purpose,
further theoretical and experimental research has to be performed which
requires an extensive use of computer simulation.
The Non-Equilibrium Green's Functions (NEGF) have been successfully used to
investigate the characteristics of nanoscale silicon transistors, carbon-nanotube-based
transistors, and molecular devices. Using the NEGF formalism,
quantum phenomena, like tunneling and scattering processes, can be rigorously
modeled. With the aid of this formalism we investigated the behavior of carbon
nanotube transistors.
The effect of the scaling of the gate-source and gate-drain spacer lengths on
the device response was investigated for different barrier heights at the
metal-nanotube interface. Electron-phonon interaction parameters, such as
electron-phonon coupling strength and phonon energy, strongly depend on the
chirality and the diameter of the carbon nanotube. The steady-state and
dynamic response of carbon-nanotube-based transistors have been studied for a
wide range of electron-phonon interaction parameters. Based on the results,
methods for improving the performance of nanotube transistors have been
proposed.
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