Effect of oxygen plasma on the optical properties of monolayer graphene

Abstract

The significant alteration of absorption (A) of monolayer graphene under mild oxygen plasma exposure has been observed. The first important effect is the reduction of the excitonic resonance peak at 4.64 eV. Secondly, in the near infrared range, A is gradually suppressed below an exposure-dependent threshold in sense that A ≪ A0. Quantity A0 (given by πα and α is the fine structure constant) denotes constant absorption and relates to universal optical conductivity σ0. The suppression of A0 can be thought as the weakening of electron-hole interaction as displayed by the reduction of the excitonic resonance peak at 4.64 eV. The weakening of this interaction is due to the disorder introduced by the oxygen plasma exposure. © (2014) Trans Tech Publications, Switzerland.