Catalysed by the success of mechanical exfoliated free-standing graphene, two dimensional
(2D) semiconductor materials are successively an active area of research. Silicene is a monolayer
of silicon (Si) atoms with a low-buckled honeycomb lattice possessing a Dirac cone and massless
fermions in the band structure. Another advantage of silicene is its compatibility with the Silicon
wafer fabrication technology. To effectively apply this 2D material in the semiconductor industry, it
is important to carry out theoretical studies before proceeding to the next step. In this paper, an overview
of silicene and silicene nanoribbons (SiNRs) is described. After that, the theoretical studies to
engineer the bandgap of silicene are reviewed. Recent theoretical advancement on the applications of
silicene for various field-effect transistor (FET) structures is also discussed. Theoretical studies of
silicene have shown promising results for their application as FETs and the efforts to study the performance
of bandgap-engineered silicene FET should continue to improve the device performance.
A continuum of compass spin models on the honeycomb lattice