Wrinkled bilayer graphene with wafer scale mechanical strain

Wafer-scale strained bilayer graphene is demonstrated by employing a silicon nitride (Si₃N₄) stressor layer. Different magnitudes of compressive stress up to 840 MPa were engineered by adjusting the Si₃N₄ deposition recipes, and different strain conditions were analyzed using Raman spectroscopy. The strained graphene displayed significant G peak shifts and G peak splitting with 16.2 cm^-1 and 23.0 cm^-1 of the G band and two-dimensional band shift, which corresponds to 0.26% of strain. Raman mapping of large regions of the graphene films found that the largest shifts/splitting occurred near the bilayer regions of the graphene films. The significance of our approach lies in the fact that it can be performed in a conventional microfabrication process, i.e., the plasma enhanced chemical vapor deposition system, and thus easily implemented for large scale production.