The Role of Metal−Nanotube Contact in the Performance of Carbon Nanotube Field-Effect Transistors

TLDR

Single‑wall carbon nanotube field‑effect transistors behave as Schottky barrier devices, but the factors controlling the barrier size remain unclear. We present the first statistical analysis of the factors controlling the Schottky barrier size in CNFETs. A model relating the on‑current to a tunneling barrier whose height depends on nanotube diameter and source/drain metal type explains a data set of over 100 devices. The study identifies the optimal combination of tube diameter and metal type for CNFET performance.

Abstract

Single-wall carbon nanotube field-effect transistors (CNFETs) have been shown to behave as Schottky barrier (SB) devices. It is not clear, however, what factors control the SB size. Here we present the first statistical analysis of this issue. We show that a large data set of more than 100 devices can be consistently accounted by a model that relates the on-current of a CNFET to a tunneling barrier whose height is determined by the nanotube diameter and the nature of the source/drain metal contacts. Our study permits identification of the desired combination of tube diameter and type of metal that provides the optimum performance of a CNFET.