Are Argon and Nitrogen Gases Really Inert to Graphene Devices?

Abstract

Argon and Nitrogen in their gaseous state are used to provide an inert environment either during probing electronic materials and devices or processing such devices. Although these gases are relatively inert with bulk materials, the gases, however, can interact with different surfaces and influence device physics and surface chemistry. Graphene, a monolayer 2D material, can be influenced by these gases, especially in carbon vacancy and Stone Wales (SW) point defects, which are inherently present in graphene due to growth or synthesis challenges. In this work, we have explored the interaction of graphene with argon and nitrogen in the presence of carbon vacancy and SW point defects based on Density Functional Theory (DFT) and Non-Equilibrium Greens Function (NEGF) computational methods using the QuantumATK simulation tool. We have investigated that, although nitrogen and argon are inert to pristine graphene, the gases enhance their orbitals overlap with graphene in the presence of these defects. Fundamental properties of graphene which drive corresponding device behavior, like band structure, trap states, and fermi energy level, are perturbed by this enhanced interaction. NEGF study reveals that channel current in graphene devices can be degraded due to the influence of these gases in the presence of carbon vacancy and SW defects.