Selective femtosecond laser ablation of graphene for its micro-patterning Available to Purchase

Due to the outstanding electrical properties of graphene, the demand of its clean and well-defined micro-structures for diverse applications has increased. However, fabrication of such micro-structured graphene is difficult due to handling and machining problems. Femtosecond lasers are versatile tools for controlled ablation and resulting patterning process. In this paper, we present the selective ablation and functionalization of monolayers of graphene on 300 nm thick thermally grown silicon dioxide on silicon substrates with a Ti:sapphire laser (λ = 800 nm, τ = 40 fs). Investigations were performed on the micro- patterns in graphene ablated by the laser in the fluence range of 0.9-2.2 J/cm². Just below the ablation threshold functionalization of the graphene layer was obtained. The resolution of the patterning was in the range of a few micrometers. In order to study the effect of oxidation of graphene at the ablation rim, the experiments were conducted both under ambient and inert gas atmosphere conditions. The morphology of the irradiated region of graphene was evaluated with optical microscopy, scanning electron microscopy and atomic force microscopy. With Raman spectroscopy the complete removal of graphene was ascertained. Finally, we find that femtosecond laser ablation is a promising method for direct writing of micro-patterns in graphene monolayers for various potential applications, e.g. for electrodes of thin film transistors.