A comprehensive analytical study of electrical properties of carbon nanotube field‐effect transistor for future nanotechnology

Abstract

This paper discusses a comprehensive analytical study of electrical properties of single‐wall conventional carbon nanotube field‐effect transistor (CNTFET) devices of subthreshold swing (SS), transconductance (gm), and extension resistance. The analytical expressions for SS and gm have been derived based on channel modulated potential. In the study, it was observed that SS value of the CNTFET device is equal to 60 mV/decade, which is smaller than the conventional and double gate metal‐oxide‐semiconductor field‐effect transistors. The subthreshold swing degrades at larger tube's diameter and gate‐source voltage due to increased source‐drain leakage current. Carbon nanotube field‐effect transistor devices achieve larger gm at large gate‐source voltage, which has a disadvantage of reducing the allowable voltage swing at the drain. The extension resistance of the device falls with diameter of the tube.

Coupled NEGF-PSO method for maximizing the current ratio of CNTFETs based on oxide thickness optimization

“…The same zero electric field conditions have been assumed for other boundaries. The Green function of CNT has been calculated from equation5 [6,21]:…”

“…Until a self-consistent potential is acquired, the steps of solving the 2D Poisson equations and coupled NEGF must be repeated. By means of the Landauer-Buttiker formula, the drain current for coherent transport under a bias voltage V can be calculated after the once self-consistency is achieved [21,22,23]:…”