Effects of Functionalization and Stress on Graphene Electronic Properties: Focusing on Bandgap

Abstract

Graphene is considered as a promising base material for nanodevices due to the excellent mechanical, thermal and electronic properties. However, when developing 2D semiconductor device such as a field-effect transistor, one obstacle we are facing is the zero bandgap of pure graphene, which makes it hard to apply to the semiconductor field. In this study, we verify the feasibility of opening the bandgap by functionalizing a graphene and adding stresses based on first principle calculations, where hydroxyl and epoxy groups are used. The effect on bandgap is also observed in the calculations after adding stress about a few GPa. The results show that bandgaps of 1~2 eV in functionalized graphene were opened and stresses of 1GPa induced slightly variations of bandgaps. The electron density differences indicate that the loaded functional groups take away the charge of graphene, making it a betatopic system. Our study may provide a potential method to modify the electronic properties of two-dimensional materials.