Electronic properties and work functions of silicane/fully hydrogenated h-BN and silicane/graphane nanosheets

In this work, density functional theory (DFT) computations with van der Waals (vdW) corrections were performed to investigate the dihydrogen bondings and their effects on the electronic and work functions of graphane/silicane bilayer and fully hydrogenated hexagonal boron nitride (fhBN)/silicane bilayer. The type of dihydrogen bonding (C-H···H-Si or N-H···H-Si) greatly affected the stability, electricity and photology of the bilayers, leading to significant band gap and work function modifications of the nanosystems. Interestingly, the fhBN/silicane bilayer combined by N-H···H-Si bilayers has an energy gap (~0.533 eV) much lower than those of individual building blocks fHBN and silicane monolayer, and the work function (3.11 eV) of the fhBN/silicane bilayer combined by B-H···H-Si bilayers is much lower than that of graphene and other traditional metals. Changing the direction and strength of external electric field can effectively tune the band gap and work function of the bilayers, correspondingly cause a semiconductor-metal transition in the band gap and the work function showed a widely tunable range. These results offer new opportunities for developing electronic and opto-electronic devices based on graphane/silicane bilayer and fhBN/silicane bilayer.