Title: Characterization of Graphene Field-Effect Transistors for High Performance Electronics
Description: It is an ongoing effort to improve field-effect transistor (FET) performance. With silicon transistors approaching their physical limitations, alternative materials that can outperform silicon are required. Graphene, has been suggested as such an alternative mainly due to its two-dimensional (2D) structure and high carrier velocities. The band structure limits achievable bandgaps, preventing digital electronic applications. This, however, does not rule out analog electronic applications at high frequencies, where the full potential of improved carrier speeds in graphene can be exploited. In this thesis, the high-bias characteristics of graphene FETs are investigated. Current saturation as well as the effect of ambipolar conduction on the current-voltage characteristics are studied. A field-effect model is developed that can capture the effects of the unique band structure, such as a density-dependent saturation velocity. The effect of channel length scaling in these devices is studied down to 100-nm channel length with the aid of pulsed-measurement techniques.

Transistors RF performance and bias dependence of high frequency behavior is explored. Novel fabrications methods are developed to improve FET performance. A technique is developed to grow metal-oxides on graphene surface for efficient gate coupling. An alternative approach to making high quality devices is realized by incorporating hexagonal-boron nitride as a gate dielectric. These transistors exhibit the potential of graphene electronics for high-performance analog electronic applications.