Sizable Band Gap in Epitaxial Bilayer Graphene Induced by Silicene Intercalation
Hui Guo, Ruizi Zhang, Hang Li, Xueyan Wang, Hongliang Lu, Kai Qian, Geng Li, Li Huang, Xiao Lin, Yuyang Zhang, Hong Ding, Shixuan Du, Sokrates T. Pantelides, Hongjun Gao
Abstract
Opening a band gap in bilayer graphene (BLG) is of significance for potential applications in graphene-based electronic and photonic devices. Here, we report the generation of a sizable band gap in BLG by intercalating silicene between BLG and Ru substrate. We first grow high-quality Bernal-stacked BLG on Ru(0001) and then intercalate silicene to the interface between the BLG and Ru, which is confirmed by low-energy electron diffraction and scanning tunneling microscopy. Raman spectroscopy shows that the G and 2D peaks of the intercalated BLG are restored to the freestanding-BLG features. Angle-resolved photoelectron spectroscopy measurements show that a band gap of about 0.2 eV opens in the BLG. Density functional theory calculations indicate that the large-gap opening results from a cooperative contribution of the doping and rippling/strain in the BLG. This work provides insightful understanding on the mechanism of band gap opening in BLG and enhances the potential of graphene-based device development.