Theoretical prediction of eliminating the buffer layer and achieving charge neutrality for epitaxial graphene on 6H-SiC(0001) via boron compound intercalations

Charge neutrality is vital to improve the performance of electronic devices based on epitaxial graphene grown on SiC substrates. First-principle calculations are applied to predict the charge-neutral epitaxial graphene by intercalating B3C5 layer between the SiC substrate and a buffer carbon layer. The electronic structure of graphene is found to be modulated by adjusting the B:C ratio of a series of BxCy intercalation layers. The buffer layer is eliminated and the intrinsic n-doping of as-grown graphene is avoided by preventing the charge transfer between graphene and the SiC substrate. The calculated surface energy of the B3C5-intercalated structure shows considerable stability as compared to the other intercalated structures over a wide range of temperatures and pressures under B-rich conditions. These findings will promote the practical application of B3C5-intercalated epitaxial graphene on SiC(0001) as a core element of microelectronic devices at high temperature, or pressure sensors at variable pressure conditions. (C) 2020 Elsevier Ltd. All rights reserved.