Multiscale Modeling for Graphene-Based Nanoscale Transistors

The quest for developing graphene-based nanoelectronics puts new requirements on the science and technology of device modeling. It also heightens the role of device modeling in the exploration and in the early assessment of technology options. Graphene-based nanoelectronics is the first form of molecular electronics to reach real prominence, and therefore the role of single atoms and of chemical properties acquires more relevance than in the case of bulk semiconductors. In addition, the promising perspectives offered by band engineering of graphene through chemical modifications increase the role of quantum chemistry methods in the assessment of material properties. In this paper, we review the multiphysics multiscale (MS) approaches required to model graphene-based materials and devices, presenting a comprehensive overview of the main physical models providing a quantitative understanding of the operation of nanoscale transistors. We especially focus on the ongoing efforts to consistently connect simulations at different levels of physical abstraction in order to evaluate materials, device, and circuit properties. We discuss various attempts to induce a gap in graphene-based materials and their impact on the operation of different transistor structures. Finally, we compare candidate devices in terms of integrated circuit performance and robustness to process variability.