Plasma Treatment in Graphene Exfoliation: Comparing a Handheld Corona Device to Oxygen Plasma in Pre-Treating SiO₂ Wafers

We test the use of a portable corona system in lieu of an oxygen plasma chamber for pre-treating SiO₂ wafers ahead of graphene exfoliation. Often used in the plastic film industry and the bonding of polymers and composites, corona treatment has an established role in improving the adhesion between materials. In graphene exfoliation, oxygen plasma is a popular implementation to the fabrication process due to its thorough cleaning of adsorbates from the substrate surface, improving the surface interaction between the graphite and the silicon oxide substrate. However, oxygen plasma systems are seldom portable and can be large and costly, and in lieu of a more accessible oxygen option, other plasmas may be explored for graphene exfoliation. While argon plasma has already been studied, a handheld corona surface treater that creates air plasma, like the BD-20AC Laboratory Corona Treater from Electro-technic Products, has not been tested despite its portability and affordability. To determine its effectiveness, the corona device is tested against an oxygen plasma chamber on SiO₂ chips while varying factors like time of exposure and the type of graphite. We find that the corona device performs worse than the traditional oxygen plasma in terms of few-layer graphene exfoliation yield, supporting the corona’s absence from current graphene exfoliation procedures.