UC Santa Barbara

This PhD dissertation explores the potential of two-dimensional (2D) layered materials to revolutionize computing and communication beyond today's electronics. The invention of metal-oxide-semiconductor field-effect-transistor (MOSFET) in the late 1959 has driven the need for dimensional scaling and new applications, making 2D materials with their exotic structural, physical, electrical, and magnetic properties, an attractive solution. This thesis will first present a comprehensive analysis of the various electrical contact topologies to 2D materials, leading to the development of the first comprehensive numerical model for contact resistance, addressing efficient charge injection. This work lays the foundation for the next stage of my research, which involves developing a comprehensive mobility model for quantifying transport in 2D materials to aid the design of high-performance 2D-FETs.By coupling the electrical charge injection and transport models, this thesis will discuss the results of the first comprehensive scaling analysis of 2D materials in emerging gate-all-around architectures, enabling the design of ultra-energy-efficient and compact transistors for sustaining Moore’s law. Further energy-efficiency gains can be achieved through use of steep-slope 2D-Tunneling Field-Effect-Transistors (2D-TFETs), and this thesis will then present the first compact model for such devices. This model is then used to benchmark 2D-TFET device performance in emerging neuromorphic (NM) computing architectures, designed with both neuronal and synaptic functionalities. The simulations promise impressive energy-efficiency gains of close to three orders of magnitude compared to state-of-the-art MOSFETs. In addition to the conventional charge-based computing methodologies, spin-based computing is another alternative computing platform that offers an additional route for energy-efficient computing. However, there are two major drawbacks to realizing useful spin-based computing devices with 2D-materials, and they are – efficient spin injection, and efficient spin transport. In the next section, therefore, the thesis will discuss the role of contact anisotropies in contacts to 2D-materials for efficient spin injection, and then develop the framework for modeling spin-transport in these materials. Therefore, by judiciously exploiting and manipulating both the charge- and quantum-information of these devices, significant improvements in energy efficiency beyond what is currently achievable can be realized, leading to a brighter, happier, and safer life.