A semiconductor device has a substrate and graphene with semiconducting properties or diamond region formed on the substrate. The graphene with semiconducting properties or diamond region is formed on or within the substrate using liquid-phase-epitaxy growth of graphene enabled by a catalytic alloy of Ni and Cu. The substrate can be silicon, silicon carbide, gallium arsenide, gallium nitride, germanium, or indium phosphide. A semiconductor component is formed over the graphene with semiconducting properties or diamond region and substrate. The semiconductor component can be a power MOSFET, IGBT, or CTIGBT with a gate structure formed over the substrate, source region adjacent to the gate structure, and drain region adjacent to the gate structure opposite the source region. The graphene with semiconducting properties or diamond region is formed under a gate of the MOSFET to reduce drain to source resistance, as well as providing radiation hardening for the device.