5.2 Asymmetric Single-Gate Design

In Section 5.1 we showed that an extra gate close to the drain-sided SCHOTTKY barrier can effectively suppress the parasitic current, which results from ambipolar conduction. However, due to some technological limitations using an extra gate may not be suitable for some applications. In this section we show that by asymmetric scaling of the gate-source and gate-drain spacer length of a single-gate device the ambipolar conduction can be reduced. Furthermore, appropriate selection of the gate-source and gate-drain spacer length results in considerable reduction of parasitic capacitances. As a result, improved device characteristics can be achieved. Results for devices with different barrier heights at the metal-CNT interface are discussed.


M. Pourfath: Numerical Study of Quantum Transport in Carbon Nanotube-Based Transistors