Studies of growth technics and homogenous of graphene formed on 4° off-axis 4H-Si-face SiC

The growth technics of graphene formed on the (0001) surface of 4H-SiC by annealing in a reversed graphite crucible inside ultra-high vacuum is studied by Raman spectra together with scanning electron microscopy(SEM). In reversed graphite crucible, this sublimation occurs more slowly, so that higher temperature (>1680°C) and longer time(>40 minutes) are required to obtain films of high quality, comparable thickness and large area. The quality and homogenous of graphene have been studied with SEM, Raman spectra and AFM. It is demonstrated that the epitaxial graphene (EG) formed on crucible-capped SiC evidently has good quality without the increase of epitaxial graphene layers, extending the pyrolysis time is beneficial to carbon recombination for high quality epitaxial graphene.