Engineering the field emission properties of graphene film by gas adsorbates

We study the effect of different gas adsorbates (N₂, O ₂, and CO₂) on the field emission (FE) properties of graphene film. Our experimental measurements show that, except for N ₂, 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 N ₂ adsorbed graphene is negligible. A "depolarization electric field model" is then proposed to explain the observed FE hysteresis behavior. This journal is