Carbon nanotube Schottky diodes performance study: static and high-frequency characteristics

A systematic study of carbon nanotube (CNT)-based Schottky diodes is performed by means of numerical device simulations and compact modeling. The static performance is discussed for CNT devices with chemical or electrostatic doping achieved by increasing the carrier concentration and by adding additional gates, respectively. The device is designed with an optimized substrate and a horse-shoe shaped coplanar access both suitable for high-frequency applications. Diode performance indicators such as rectifying factor and storage time are obtained and compared to experimental data. Based on the equivalent circuit analysis at forward bias and the Shockley diode equation, intrinsic and extrinsic cutoff frequencies for gate-less devices are obtained. Further device optimization could lead to an improved cutoff frequency as shown by assuming an improved contact transparency and multitube devices. This performance study is intended to aid the technology development of CNT-based diodes for specific applications.