Carbon-Nanotube Field-Effect Transistors with Very High Intrinsic Transconductance

We investigated intrinsic transconductance of carbon-nanotube field-effect transistors (CNTFETs) with carbon nanotubes (CNTs) grown by chemical vapor deposition. The measured transconductance at a drain voltage of -1 V was 8.7 µS for a CNT with a diameter of 1.5 nm. Very high intrinsic transconductance of 20 µS was estimated by considering the contribution of parasitic resistance. Apparent and intrinsic transconductance per unit channel width were 5800 µS/µm and 13000 µS/µm, respectively. These are considerably larger than those for the state-of-the-art Si metal oxide semiconductor field effect transistors (MOSFETs). Parasitic resistance is dominated by the resistance of the CNT portions between the gate and contacts. We expect the performance of CNTFETs will advance further by improving CNT quality and by optimizing device structures.