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

Abstract

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.