Schottky junction properties of graphene with nitrogen and gallium polar freestanding GaN

Integration of two-dimensional (2D) layered materials like graphene with conventional semiconductors is of great interest to develop high performance optoelectronics and other electronic devices. Gallium nitride (GaN) with a direct bandgap (~3.4 eV) has been widely explored for optoelectronic and power device applications. Recently, freestanding GaN has been grown by liquid phase epitaxy. GaN device properties can be significantly changed depending on the nitrogen (N) and gallium (Ga) polar surface. In the present work, we have explored the Schottky junction properties of graphene with N and Ga polar freestanding GaN. Interestingly, Ga-polar graphene/GaN heterostructure showed higher photoresponsivity than the N-polar graphene/GaN heterostructure.