QUANTUM ELECTRON DYNAMICS OF SOME NANODEVICES

Abstract

The purpose of the current thesis is to explore the characteristics of quantum carrier transport of a single walled carbon nanotube quantum dot field-effect-transistor (SWCNTFET) subjected to both a magnetic field and an ac-field (mid infrared region). The effect of tensile strain for zigzag, chiral and armchair SWCNTs will be taken into consideration. Also, it is interesting to investigate the thermoelectric effect, that is, Seebeck and Peltier coefficients in the present different types of strained single walled carbon nanotube quantum dot field effect transistor (SWCNTFET) under the influence of an ac-field with frequency in the mid infrared region and magnetic field. This nanodevice can be modeled as follows: SWCNT in the form of quantum dot is connected to two metallic leads. These two metallic leads operate as a drain and a source. In this three-terminal device, the conducting substance acts as the gate electrode. Governing the Switching and the electrostatics of the carbon nanotube channel is realized by using another metallic gate. The back gate controls the substances at the carbon nanotube quantum dot/metal contact. Landauer-Buttiker formula using to deduce the electric current. Also by using the WKB approximation method, the photon-assisted tunneling probability is deduced. The strained band gap energy for all types of SWCNT is expressed in terms of the induced tensile strain. This band gap energy depends on the chiral indices for every type (armchair, zigzag, chiral) of the single walled carbon nanotube. In our calculations, we consider different chiral indices for every type of SWCNT.