Laser-induced graphene van der Waals contact-enabled high-performance 2D-materials-based field-effect transistor

Establishing robust electrical contact between electrodes and two-dimensional (2D) semiconductors has become an increasingly critical challenge in realizing high-performance 2D material-based devices. This study presents an easy-to-fabricate high-quality van der Waals (vdW) contact strategy, utilizing transferred laser-induced graphene (LIG), for monolayer graphene field-effect transistors (LIG-GFETs). LIG-graphene vdW contacts were formed via a simple transfer and alignment step without any high-temperature or vacuum processes. Excellent electrical properties of LIG-GFETs were achieved, with up to sevenfold enhanced carrier mobilities compared to conventional gold electrode-based GFETs. Experimental investigations and density functional theory simulations elucidated the mechanisms underlying this performance enhancement. Specifically, the superior performance of LIG-GFETs can be attributed to the formation of vdW contacts between the transferred LIG and the monolayer graphene, alongside the doping of the monolayer graphene induced by the O functional groups in the LIG. We also demonstrated that the high performance monolayer MoS2 FETs can be achieved with more than fivefold enhanced carrier mobilities by using LIG vdW contact compared to conventional gold electrode-based MoS2 FETs. This newly developed vdW contact strategy provides new insights into high-performance 2D material-based devices.