Study on optical interference effect of graphene oxide films on SiO2 and Si3N4 dielectric films

The optical interference effect has enabled the visualization of thin layers, even monolayers, of graphene by simple optical microscopy. In this study, we have controlled the optical interference effect by changing the thickness and types of dielectric films, i.e. SiO2 and Si3N4. By investigating differences in RGB parameters between the graphene oxide layer and the dielectric layer, conditions for the highest visibility of the graphene oxide layer were determined. We also studied colors as a function of graphene oxide layer thickness and dielectric layer thickness. These color patterns can be effectively presented as two-dimensional color charts. When comparing SiO2 and Si3N4 as dielectric layers, each layer was found to exhibit different interference fringe patterns, which is due to a mismatch of optical properties between the material layer and dielectric layer. The effects of optical properties (n, k) of the material layer on interference colors were also investigated.