Direct Synthesis of Layer-Tunable and Transfer-Free Graphene on Device-Compatible Substrates Using Ion Implantation

Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device applications. Here, we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual-metal smart Janus substrate for a diffusion-limiting graphene formation, to directly synthesize layer-tunable graphene on arbitrary substrates without the post-synthesis layer transfer process. C ion implantation was performed on Cu-Ni film deposited on a variety of device-relevant substrates. Upon thermal annealing to promote Cu-Ni alloying, the pre-implanted C-atoms in the Ni layer are pushed towards the Ni/substrate interface by the top Cu layer due to the poor C-solubility in Cu. As a result, the expelled C-atoms precipitate into graphene structure at the interface facilitated by the Cu-like alloy catalysis. After removing the alloyed Cu-like surface layer, the layer-tunable graphene on the desired substrate is directly realized. ReaxFF was performed to elucidate the graphene formation mechanisms in this novel synthesis approach. Three ordinary devices using as-synthesized graphene were fabricated on Si, SiO2, and glass substrates to demonstrate the graphene quality of our layer-tunable and transfer-free synthesis approach and the excellent performance characteristics of these low-cost manufacturing devices: field-effect transistors, heating devices, and near-infrared photodetectors.