  We report on a new method for graphene synthesis and assessment of the
properties of the resulting large-area graphene layers. Graphene was produced
by the high pressure - high temperature growth from the natural graphitic
source by utilizing the molten Fe-Ni catalysts for dissolution of carbon. The
resulting large-area graphene flakes were transferred to the silicon - silicon
oxide substrates for the spectroscopic micro-Raman and scanning electron
microscopy inspection. The analysis of the G peak, D, T+D and 2D bands in the
Raman spectra under the 488-nm laser excitation indicate that the high pressure
- high temperature technique is capable of producing the high-quality
large-area single-layer graphene with a low defect density. The proposed method
may lead to a more reliable graphene synthesis and facilitate its purification
and chemical doping.
