Two-dimensional silicon nanosheets

Since the discovery of graphene, a single-atom-thick honeycomb carbon structure, a great deal of effort has been both theoretically and experimentally dedicated to the search for similar two-dimensional (2D) materials comprising group-IV elements, especially silicon. If silicene is to be used under ambient conditions, 2D silicon nanosheets (SiNSs) with sp3 silicon bonds should be selected. CaSi₂, one of the Zintl phases, is an intermetallic compound formed between a strongly electropositive metal and a somewhat less electropositive atom such as Si. CaSi₂, considered a calcium-intercalated silicene, provides a good opportunity to investigate the intrinsic electronic structure of genuine silicene. Bilayer silicene generally exists as a multiphase compound in CaSi₂Fx. The w-BLSi structure apparently resembles that of re-BLSi, although their atomic arrangements are clearly different. The chemical modification-exfoliation process provides a generic approach for preparing organo-chapped silicenes. In this method, layered polysilane (Si6H6) was used as a starting layered silicon compound with sp3 silicon bonding.