Robust Laser‐Induced Graphene‐Boron‐Doped Diamond Nanowall Hybrid Nanostructures with Enhanced Field Electron Emission Performance for Microplasma Illumination Devices

This investigation introduces a scalable fabrication method for laser-induced graphene (LIG)-boron-doped diamond nanowall (BDNW) hybrid nanostructures, designed for field electron emission (FEE) cathode materials in microplasma illumination (μPI) devices. The two-step process involves fabricating BDNWs via microwave plasma-enhanced chemical vapor deposition, followed by drop-casting BDNW dispersion onto polyimide foils to create LIG-BDNW hybrid nanostructures. Topographic studies reveal that BDNWs on LIG boosts surface area and prevent graphene restacking. High-resolution transmission electron microscopy confirms precise BDNW decoration, creating sharp edges and high porosity. The effects of boron and nitrogen dopants, highlighted by Raman spectroscopy, are corroborated by near-edge X-ray absorption fire structure and X-ray photoelectron spectroscopies. The hybrid nanostructures exhibit high electrical conductivity and superior FEE properties, with a low turn-on field of 2.9 V μm^-1, a large FEE current density of 3.0 mA cm^-2 at an applied field of 7.9 V μm^-1, and a field-enhancement factor of 5,480. The hybrid nanostructures demonstrate an exceptionally low breakdown voltage of 320 V and a plasma current density of 9.48 mA cm^-1 at an applied voltage of 550 V. Ab-initio calculations of the electronic structure further support the experimental findings of these diamond-graphene hybrids, underscoring their potential in advanced electronic applications.