The electric field in term of the description of dipole correction or saw-tooth potential is not implemented. To consider the electric filed perpendicular to the graphene, you may use the applied bias voltage in a two-probe system, in which the normal direction of bi-layer or trilayer of graphene is parallel to the transport direction (i.e. z direction) of such two-probe system. Also you can use the applied gate voltage, while in this case, the normal direction of graphene layer should be perpendicular to the transport direction.
The related topic can be found this thread:
https://forum.quantumatk.com/index.php?topic=1039.0By introducing the hole or electron doping (e.g., boron or nitrogen impurities in graphene), the Fermi level of graphene can be shifted.
Edit: Updated link / Anders Blom