Effect of biaxial strain on structural and electronic properties of graphene / boron nitride hetero bi-layer structure

In this work, structural and electronic properties of a bilayer structure composed of one single layer of graphene on top of a two dimensional hexagonal boron nitride (h-BN) has been investigated using first principle calculations based on density functional theory (DFT). Three different configurations are possible for this bilayer system namely B1, B2 and B3. In this paper biaxial strain was applied to B2 configuration and structural and electrical properties were observed. A small band gap opens for this bilayer structure though graphene is a zero gap material. Some important material parameter such as band gap, effective mass and Fermi velocity were investigated with the variation of biaxial strain. It was observed that the material remains to be a direct band gap material for the applied strain range from -12% to +12%. Interestingly, with the application of compressive strain effective mass decreases and Fermi velocity increases which is very crucial for high frequency RF devices.