Molecular beam epitaxy approach to the graphitization of GaAs„100... surfaces

The authors present a method for obtaining graphitized carbon on GaAs 100 surfaces. Carbon-doped GaAs is grown by molecular beam epitaxy before controlled thermal etching within the growth chamber. An AlAs layer beneath the carbon-doped GaAs acts as a thermal etch stop. As the GaAs is etched away, the carbon dopant atoms remain on the surface due to their low vapor pressure. The total number of carbon atoms available is precisely controllable by the doping density and thickness of the carbon-doped GaAs layer. Characteristic phonon modes in Raman spectra from the thermally etched surfaces show that the residual surface carbon atoms form sp2-bonded graphitic crystallites. © 2011 American Vacuum Society. DOI: 10.1116/1.3547716