Comparison of oxygen and air plasma treatments in the exfoliation of graphene

Oxygen plasma pretreatment of SiO2 substrates is commonly employed in graphene exfoliation. The plasma’s thorough cleaning of adsorbates from the substrate improves the surface interaction between the graphitic flakes and the substrate. However, oxygen plasma systems are seldom portable and can be large and costly. We compare few-layer graphene exfoliation yields from two oxygen plasma pretreatment recipes to low-pressure air plasma pretreatment, portable corona system pretreatment, and a control. We test each condition with both Kish graphite and highly oriented pyrolytic graphite. We find some evidence that these alternatives generally perform worse than the traditional oxygen plasma, supporting their absence from current graphene exfoliation procedures. There are indications of significant differences between the impact of these pretreatments for the different types of bulk graphite.