Band-gap modulation of C4H nanosheets by interlayer weak interaction and external electric field: a computational study

Abstract

The patterned hydrogenated graphene with a formula of C4H is one of the most important graphene derivatives due to its unique structural and electronic properties. However, the rather large band gap has significantly restricted the wider applications of C4H monolayer in microelectronics. In this work, by means of van der Waals corrected density functional theory (DFT) computations, we demonstrated that there could exist the unique C–H/π, C–H/H–C or π/π interaction at the interface of two C4H monolayers, resulting in the formation of C4H bilayer with different stacking patterns. Remarkably, due to the significant difference in electrostatic potential between two monolayers, the C4H bilayer assembled by the C–H/π interaction has a much lower band gap than that of C4H monolayer. Moreover, the band gap of C4H bilayer can be further reduced by applying an external electric field. Our results would pave the way for utilizing C4H nanosheets in microelectronics and call for more efforts in using weak interactions for band-structure engineering.