Highly Effective Conductance Modulation in Planar Silicene Field Effect Devices Due to Buckling

Silicene is an exciting two-dimensional material that shares many of graphene's electronic properties, but differs in its structural buckling. This buckling allows opening a bandgap in silicene through the application of a perpendicular electric field. Here we show that this buckling also enables highly effective modulation of silicene's conductance by means of an in-plane electric field applied through silicene side gates, which can be realized concurrently within the same silicene monolayer. We illustrate this by using silicene to implement Self-Switching Diodes (SSDs), which are two-dimensional field effect nanorectifiers realized within a single silicene monolayer. Our quantum simulation results show that the atomically-thin silicene SSDs, with sub-10 nm dimensions, achieve a current rectification ratio that exceeds 200, without the need for doping, representing a 30 fold enhancement over graphene SSDs. We attribute this enhancement to a bandgap opening due to the in-plane electric field, as a consequence of silicene's buckling. Our results suggest that silicene is a promising material for the realization of planar field effect devices.