Total Ionizing Dose Effects on hBN Encapsulated Graphene Devices

The constant-voltage electrical stress and 10-keV x-ray irradiation responses of encapsulated graphene-hBN devices are evaluated. Both constant-voltage stress and x-ray exposure induce only modest shifts in the current and the Dirac point of the graphene. Charge trapping at or near the graphene/BN interface is observed after x-ray irradiation. The experimental results suggest that net hole trapping occurs in the BN at low doses and that net electron trapping occurs at higher doses. First-principles calculations also demonstrate that hydrogenated substitutional carbon impurities at B/N sites at or near the graphene/BN interface can play an additional role in the radiation response of these structures.