Studies of interfacial layers between 4H-SiC (0001) and graphene

The region between epitaxial graphene and the SiC substrate has been investigated 4H-SiC (0 0 0 1) samples were annealed in a high temperature molecular beam epitaxy system at temperatures between 1100 and 1700 degrees C The interfacial layers between the pristine SiC and the graphene layers were studied by X-ray photoelectron spectroscopy Graphene was found to grow on the SiC surface at temperatures above 1200 degrees C Below this temperature, however, sp(3) bonded carbon layers were formed with a constant atomic Si concentration C1s and Si2p core level spectra of the graphene samples suggest that the interface layer we observe has a high carbon concentration and its thickness increases during the graphitization process A significant concentration of Si atoms is trapped in the interface layer and their concentration also increases during graphitization (C) 2009 Elsevier Ltd All rights reserved