High Performance n-Type Carbon Nanotube Field-Effect Transistors with Chemically Doped Contacts

Abstract

Short channel (∼80 nm) n-type single-walled carbon nanotube (SWNT) field-effect transistors (FETs) with potassium (K) doped source and drain regions and high-κ gate dielectrics (ALD HfO₂) are obtained. For nanotubes with diameter ∼1.6 nm and band gap ∼0.55 eV, we obtain n-MOSFET-like devices exhibiting high on-currents due to chemically suppressed Schottky barriers at the contacts, subthreshold swing of 70 mV/decade, negligible ambipolar conduction, and high on/off ratios up to 10⁶ at a bias voltage of 0.5 V. The results compare favorably with the state-of-the-art silicon n-MOSFETs and demonstrate the potential of SWNTs for future complementary electronics. The effects of doping level on the electrical characteristics of the nanotube devices are discussed.