Short Channel Field-Effect Transistors from Highly Enriched Semiconducting Carbon Nanotubes

Semiconducting single-walled carbon nanotubes (s-SWNTs) with a purity of ~98% have been obtained by gel filtration of arc-discharge grown SWNTs with diameters in the range 1.2–1.6 nm. Multi-laser Raman spectroscopy confirmed the presence of less than 2% of metallic SWNTs (m-SWNTs) in the s-SWNT enriched sample. Measurement of ~50 individual tubes in Pd-contacted devices with channel length 200 nm showed on/off ratios of > 10⁴, conductances of 1.38–5.8 μS, and mobilities in the range 40–150 cm²/(V·s). Short channel multi-tube devices with ~100 tubes showed lower on/off ratios due to residual m-SWNTs, although the on-current was greatly increased relative to the devices made from individual tubes.