Diameter optimisation for highest DoB of CNT-FETs

Abstract

Carbon nanotube (CNT) is one of the most significant materials for the development of faster and improved performance of nanoscaled transistors. This work aims at analysing a trade-off between device performance and device size of CNT-based transistor. Acoustic and optical phonon (OP) scattering along with the elastic scattering lead to the non-ballistic performances of those transistors. The main focus of this work is mainly on finding an optimum diameter to obtain the highest degree of ballisticity (DoB) from both single-walled (SWCNT-FET) and double-walled CNT field-effect transistors (DWCNT-FET). At first, an n-type SWCNT-FET has been considered and the diameter dependence on DoB has been simulated. The effects of drain voltage, gate voltage and channel length have been investigated for such characteristics followed by a comparison with DWCNT-FET structure. First of all, it has been found that DoB along with the optimum diameter increases with the increase of (VDS-VGS). The increase of channel length, however, degrades the ballistic performance demanding a higher diameter to reach the optimum point. Finally, it can be concluded that optimum diameter for DWCNT-FET reaches earlier than SWCNT-FET but at lower DoB.