Enhanced Subthreshold Slopes in Large Diameter Single Wall Carbon Nanotube Field Effect Transistors

The performance of single wall carbon nanotube field effect transistors (SWNT FETs) is greatly affected by the quality of its contacts. The presence of Schottky barriers imposes a strong scaling of the gate dielectric thickness. Here, we employ large diameter SWNTs in order to fabricate ohmically contacted FETs when a lower work function but higher adhesion strength metal such as Cr is used. A subthreshold slope as low as 113 mV/dec is obtained even when employing a thick, 200 nm SiO$_{2}$ dielectric. The result is examined in light of the positive effects of exposure to air and underlines the possibility for less stringent device fabrication techniques.