A method of forming nanocrystalline graphene according to an embodiment may include: arranging a substrate having a pattern in a reaction chamber; injecting a reaction gas into the reaction chamber, where the reaction gas includes a carbon source gas, an inert gas, and a hydrogen gas that are mixed; generating a plasma of the reaction gas in the reaction chamber; and directly growing the nanocrystalline graphene on a surface of the pattern using the plasma of the reaction gas at a process temperature. The pattern may include a first material and the substrate may include a second material different from the first material.