Decoupling graphene from SiC(0001) via oxidation

Abstract

When epitaxial graphene layers are formed on SiC͑0001͒, the first carbon layer ͑known as the "buffer layer"͒, while relatively easy to synthesize, does not have the desirable electrical properties of graphene. The conductivity is poor due to a disruption of the graphene bands by covalent bonding to the SiC substrate. Here we show that it is possible to restore the graphene bands by inserting a thin oxide layer between the buffer layer and SiC substrate using a low temperature, complementary metal-oxide semiconductor-compatible process that does not damage the graphene layer.

Effect of oxygen adsorption on the local properties of epitaxial graphene on SiC (0001)

“…Recent experiments, performed using mainly LEEM microscopy, Core level photoemission (XPS), and Electron Energy Loss Spectroscopy (EELS), have demonstrated that the graphene π band of the buffer layer can be restored by the insertion of a thin oxide layer between the buffer layer and the SiC substrate [11]. However, none of these works is centered on the effect of oxidation on the electronic properties.…”

Buffer layer free graphene on SiC(0001) via interface oxidation in water vapor

“…E-mail: Thomas.Seyller@physik.tu-chemnitz.de (Thomas Seyller) dependent [4] and it has been observed that this is a direct consequence of the presence of the buffer layer [10]. In recent years, various elements such as gold [11], lithium [12], silicon [13], fluorine [14], germanium [15], oxygen [16][17][18][19] and hydrogen [10,[20][21][22][23] have been intercalated between the buffer layer and SiC(0001) in order to modify the interface.…”

“…Oida et al [16] have investigated the intercalation of molecular oxygen under the buffer layer using a lowtemperature oxidation process (T = 250 °C, p = 1 atm, t = 5 s). They observed the formation of a 3 Å thick oxide layer below the buffer layer.…”

Studies of Li intercalation of hydrogenated graphene on SiC(0001)

“…Therefore this buffer layer is considered to be a main obstacle to the development of future electronic devices based on graphene grown on SiC(0001). Nonetheless, earlier studies have demonstrated that this buffer layer can be decoupled from the substrate and transformed into a graphene layer by hydrogen (H) [6,[10][11][12], gold (Au) [13], oxygen (O 2 ) [14] and lithium (Li) [15][16] intercalation.…”