On the possibility of zigzag and armchair silicon nanoribbons having the graphene structure

► DFT calculations predict armchair Si ribbons are stable structures but not zigzags. ► The band gap and ionization potential are predicted to decrease with ribbon length. ► Ribbons having more than 38 Si atoms are predicted to have triplet ground states. ► Al and P doped ribbons have the potential to be ferromagnetic semiconductors.