Due to the capability of ballistic transport, carbon nanotube field-effect transistors (CNTFETs) have been studied in recent years as a potential alternative to CMOS devices. CNTFETs can be fabricated with Ohmic or Schottky type contacts. Schottky barrier CNTFETs operate by modulating the transmission coefficient of Schottky barriers at the contact between the metal and the carbon nanotube (CNT) while the ohmic contact CNTFETs operate like conventional FETs.

To understand and improve the behavior of CNTFETs, a Schrödinger solver has been integrated into the device simulator Minimos-NT. The simulation results, in good agreement with experimental results, indicate the ambipolar behavior of Schottky barrier CNTFETs which limits the performance of these devices. Based on the simulation result, we developed a double gate structure which can suppress the ambipolar behavior of Schottky barrier CNTFETs considerably. By coupling Minimos-NT to SIESTA, an optimization framework, several CNTFET device characteristics optimizations have been performed.

Due to the complexity of the operation of CNTFETs, more rigorous methods for the analysis of these devices are required. Among these methods is the Non-Equilibrium Greens Function (NEGF) method which is becoming more popular for the analysis of nano-scale devices. Future work requires using more rigorous methods like the NEGF method for the analysis of CNTFETs.