Selective area growth of Bernal bilayer epitaxial graphene on 4H-SiC (0001) substrate by electron-beam irradiation

摘要

We report selective area growth of large area homogeneous Bernal stacked bilayer epitaxial graphene (BLEG) on 4H-SiC (0001) substrate by electron-beam irradiation. Sublimation of Si occurs by energetic electron irradiations on SiC surface via breaking of Si-C bonds in the localized region, which allows the selective growth of graphene. Raman measurements ensure the formation of homogeneous BLEG with weak compressive strain of -0.08%. The carrier mobility of large area BLEG is ～5100 cm~2 V~(-1) s~(-1) with a sheet carrier density of 2.2 × 10~(13) cm~(-2). Current-voltage measurements reveal that BLEG on 4H-SiC forms a Schottky junction with an operation at mA level. Our study reveals that the barrier height at the Schottky junction is low (～0.58 eV) due to the Fermi-level pinning above the Dirac point.