Methods of producing a uniformly or substantially uniformly doped relatively large area multi-layered graphene element are described comprising the steps of placing the graphene element and a dopant under low pressure conditions, and holding the graphene element and dopant at an elevated temperature for a period of time while under the low pressure conditions. In one arrangement, openings are formed in a multi-layered graphene element of relatively large area prior to doping. In another arrangement, a relatively large area multi-layered graphene element formed by an epitaxial growth technique is used. The invention also relates to an element produced using the aforementioned techniques.