Chemical Doping and Etching of Graphene: Tuning the Effects of NO Annealing

Abstract

Removal of residues from CVD-grown graphene and its doping are key issues to fully explore its properties. In the present work, we propose a two-step process to remove PMMA residuals from graphene's surface and to incorporate dopants in its lattice by NO annealing. Nevertheless, NO thermal treatments also promoted etching of the graphene layer. This effect was shown to be induced by the decomposition products of NO, which are strong oxidizing agents like NO 2 . However, this undesirable side effect of NO annealing can be strongly suppressed by carefully choosing the annealing conditions, constituting a promising approach to dope graphene.

Defect Healing in Graphene via Rapid Thermal Annealing with Polymeric “Nanobandage”

“…The D’ peak, typically seen around 1620 cm −1 is, like the D peak, associated with defects, but is not observed in our samples, perhaps because the introduction of the nitrogen induced a different defect type than previously reported. D’ peaks have previously been noted to accompany nitrogen doping in graphene, [ 42,62 ] which is hypothesized to behave similarly to a boundary‐type defect. [ 62 ] As the defect type of nitrogen‐doped graphene is not yet well studied, XPS was also used to identify the nitrogen dopants, as is discussed in detail later.…”

“…[37,38] As an example of gas absorption-based healing, graphene was healed by sequentially exposing graphene to CO and NO gases, which dopes vacancy defects with nitrogen atoms. [41][42][43] This process utilizes an adjustable ratio of CO and NO for controlled doping at room temperature. However, this approach presents an environmental and safety issue due to the toxicity of such gases.…”