Robust visibility of graphene monolayer on patterned plasmonic substrates

Area of Science:

• Materials Science
• Optics
• Nanotechnology

Background:

• Optical imaging of single and few-layer graphene flakes is challenging on arbitrary semiconductor or metal substrates.
• Graphene's invisibility on these surfaces hinders characterization and application development.

Purpose of the Study:

• To develop a method for optically imaging graphene flakes on metal substrates.
• To enhance the visibility of two-dimensional materials using plasmonic substrates.

Main Methods:

• Utilizing a submicron-sized, hexagonally packed array of gold disks on a substrate.
• Leveraging surface plasmon polaritons (SPPs) generated by the gold pattern.
• Employing a modified rigorous coupled wave analysis (RCWA) algorithm for optical property validation.

Main Results:

• Graphene flakes become visible on the patterned gold disk array via conventional microscopy.
• The interaction of SPPs with graphene alters reflectivity, increasing contrast.
• Demonstrated the robustness of graphene visibility through a parametric study.

Conclusions:

• Patterned plasmonic substrates offer a viable solution for imaging graphene.
• This method significantly improves the optical contrast of two-dimensional materials.
• Enables enhanced characterization of graphene on diverse substrates.