Conversion of the stacking orientation of bilayer graphene through high-pressure treatment

Abstract AB-stacked bilayer graphene (BLG) has wide application prospects in the field of optoelectronic devices. Chemical vapor deposition (CVD) is an important method used to prepare BLG, but no definite stacking orientation is observed between the bilayers. Besides AB stacking, a number of disordered stacking orientations that could seriously affect the performance of BLG also exist. In this paper, we report a method to control the stacking orientation of reverse-transferred CVD-BLG via high pressure environment. We found that the orientation of BLG could be changed from weak-coupling stacking to AB stacking by increasing the temperature of the solvent in the autoclave. MoS2 grains grown on graphene confirmed the stacking orientation variation of BLG. Reductions in the distance between layers in BLG under a high-pressure environment were considered to explain the observed orientation change. Reverse transfer allows the easy modification of the stacking orientation of BLG. The proposed high-pressure assistant method introduces a new route to prepare AB-stacked BLG and could be used to adjust the stacking direction of other two-dimensional materials.