Wafer-scale synthesis of multi-layer graphene by high-temperature carbon ion implantation

We report on the synthesis of wafer-scale (4 in. in diameter) high-quality multi-layer graphene using high-temperature carbon ion implantation on thin Ni films on a substrate of SiO₂/Si. Carbon ions were bombarded at 20 keV and a dose of 1 × 10¹⁵cm^-2 onto the surface of the Ni/SiO₂/Si substrate at a temperature of 500 °C. This was followed by high-temperature activation annealing (600-900 °C) to form a sp²-bonded honeycomb structure. The effects of post-implantation activation annealing conditions were systematically investigated by micro-Raman spectroscopy and transmission electron microscopy. Carbon ion implantation at elevated temperatures allowed a lower activation annealing temperature for fabricating large-area graphene. Our results indicate that carbon-ion implantation provides a facile and direct route for integrating graphene with Si microelectronics.