Through-Layer Contact with Encapsulated Graphene Using One-Step Laser Scribing

Encapsulated graphene plays a key role in enabling stable and functional operation of next-generation electronic and sensing devices. However, establishing electrical contact with encapsulated graphene remains a significant challenge because of the need for separate etching and metal deposition steps, which require complex multistep fabrication processes. This paper introduces a scalable one-step method for forming electrical contacts with encapsulated graphene using CO₂ laser scribing. This approach simultaneously etches the encapsulation layer and forms laser-induced graphene (LIG), enabling direct contact with the underlying graphene in a single step under ambient conditions. The formation of a through-layer LIG contact was experimentally verified via real-time electrical monitoring during laser scribing. This technique reliably creates electrical contacts using various organic and inorganic encapsulation layers, demonstrating broad material compatibility. Using this method, we demonstrated multilayered electrical contacts, top- and bottom-gate graphene field-effect transistors (FETs) with through-layer LIG source/drain electrodes, and sodium-selective sensors in both electrochemical and FET configurations. The proposed method simplifies fabrication and enables the low-cost, scalable integration of encapsulated graphene into next-generation electronic and sensing applications.