1 Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Strae 1, 40237 Düsseldorf, Germany 2 Semiconductor Physics Laboratory, Department of Physics and Astronomy, University of Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium
Keywords:silicene, tin sulfide, van der Waals (vdW) heterostructure, dumbbell, chalcogenide
A first principles study on the stability and structural and electronic properties of
two-dimensional silicon allotropes on a semiconducting layered metal-chalcogenide
compound, namely SnS2, is performed. The interactions between the twodimensional
silicon layer, commonly known as silicene, and the layered SnS2
template are investigated by analyzing different configurations of silicene.
The calculated thermodynamic phase diagram suggests that the most stable
configuration of silicene on SnS2 belongs to a family of structures with Si atoms
placed on three different planes; so-called dumbbell silicene. This particular
dumbbell silicene structure preserves its atomic configuration on SnS2 even at a
temperature of 500 K or as a “flake” layer (i.e., a silicene cluster terminated by H
atoms), thanks to the weak interactions between the silicene and the SnS2 layers.
Remarkably, an electric field can be used to tune the band gap of the silicene
layer on SnS2, eventually changing its electronic behavior from semiconducting
to (semi)metallic. The stability of silicene on SnS2 is very promising for the
integration of silicene onto semiconducting or insulating substrates. The tunable
electronic behavior of the silicene/SnS2 van der Walls heterostructure is very
important not only for its use in future nanoelectronic devices, but also as a
successful approach to engineering the bang-gap of layered SnS2, paving the way
for the use of this layered compound in energy harvesting applications.