Microfabricated Au and Au/graphene bilayer platelets for levitation experiments

Abstract

We describe a fabrication process for preparing liquid suspensions of micron-scale Au and Au/graphene bilayer platelets using thin-film deposition, optical lithography, ion milling, hydrofluoric acid (HF) substrate etching, and release from the substrate into a liquid suspension. Residual HF is removed through repeated centrifugation, decanting, and dilution cycles. The resulting suspension is characterized by electrospray deposition onto a secondary substrate, followed by electron and atomic force microscopy. The deposited platelets exhibit minimal aggregation, and the overall platelet yield reaches up to 30% of the platelets originally patterned on the wafer. Lateral force microscopy further confirms that the Au/graphene bilayer remains intact throughout fabrication, release, and electrospray deposition. This process provides a practical route for preparing high-quality platelet suspensions for levitated nanoparticle experiments and other applications requiring suspensions of two-dimensional nanostructures.