High current density field emission device from directly grown planar graphene via PECVD

We present a stable and efficient field electron emission device based on planar graphene directly grown on SiO ₂/Si substrates using plasma-enhanced chemical vapor deposition (PECVD). The PECVD process carried out in a hydrogen-rich environment at low temperature effectively lowers the work function through doping effects, while the defect states formed during low-temperature synthesis induce local field enhancement. These factors act synergistically to enable stable Fowler-Nordheim tunneling and reliable device operation. The transfer-free, catalyst-free process ensures high reproducibility, and the resulting device exhibits a low turn-on voltage of 7.5 V. Remarkably, the single-cell device achieved an emission current density of 400 mA/cm², while the 5 × 5 array cell device reached 300 mA/cm², both of which significantly exceed values reported for previously studied planar graphene-based emitters. These findings demonstrate that planar graphene is a promising material platform for scalable, low-power vacuum electronic applications.