Engineering the field emission properties of graphene film by gas adsorbates

Abstract

We study the effect of different gas adsorbates (N₂, O₂, and CO₂) on the field emission (FE) properties of graphene film. Our experimental measurements show that, except for N₂, adsorption of O₂ and CO₂ reduces the FE current of the graphene film. Moreover, the measured FE hysteresis loop is almost quenched after adsorbing O₂ or CO₂. The ab initio calculations quantify the experimental results by predicting a larger work function and smaller FE current for the graphene system after O₂ or CO₂ adsorption. In contrast, the change of FE properties in N₂ adsorbed graphene is negligible. A “depolarization electric field model” is then proposed to explain the observed FE hysteresis behavior.