UCLA

Graphene is a one-atom-thick 2D system that has a unique hexagonal crystal structure of two carbon atoms per unit cell. Unlike any other 2D semiconductor material known today, intrinsic graphene has a zero bandgap with its charged carriers behaving like Dirac fermions with a zero mass, resulting in many extraordinary properties that are very different from other materials. Such properties can be controllably modified by proper impurity doping or by electrical or optical modulation, making graphene extremely attractive for novel device applications. The salient electronic, optical, and optoelectronic properties of graphene, together with its unique nanostructure, offer innovative opportunities to many potentially revolutionary applications for high-speed/high-frequency electronic and optoelectronic devices, terahertz (THz) oscillators and sensors, and ultrafast nonlinear optical elements. Realization of these exciting graphene-based devices, as well as the possibility for further innovation, relies on a good understanding of graphene’s electronic, optical and optoelectronic properties in the broad spectral range from THz to the visible. In this thesis, the electronic property of graphene is investigated first, followed by the discussion of THz property of graphene. Based on the derived models of the electronic and THz properties of graphene, we can describe the plasmonic behavior of graphene in various configurations, such as graphene-based THz waveguide. A concept THz device is demonstrated both theoretically and experimentally in the last.