Field Emission Enhancement in Graphene/Cu Cathodes Through Laser‐Shock‐Induced Modulation of Geometry and Work Function

ABSTRACT Cold cathodes enable compact, low‐power vacuum microelectronics with rapid activation. Graphene/metal cathodes offer a flexible, conductive platform, but efficient field emission requires local field concentration to coincide with reduced tunneling barriers while avoiding transfer contamination. Laser shock microforming converts graphene/Cu foils into flexible cathodes in one step without transfer while modulating the local work function. High‐curvature protrusions and gradients in graphene disorder, strain, Cu microstructure, surface chemistry, and graphene/Cu coupling create spatial variations in the local emission barrier. In individual monolayer graphene/Cu protrusions, these changes produce local work function contrasts reaching 0.12 eV and align lower barriers with highly curved regions. This spatial alignment enhances field emission, yielding a turn‐on field of 4.9 V µm −1 , an emission current density of 2.2 mA cm −2 , stable emission over 32 h, and durability after 3000 bending cycles. This work extends laser shock processing from geometric shaping to coupled structural and electronic barrier control in graphene/metal cold cathodes, providing a route that can be scaled over large areas for flexible vacuum electronics.