Ultrafast Laser Ablation of Graphene under Water Immersion*

We report on a technique to pattern 2-D materials by ultrafast laser ablation. This resist-free method is performed in single step using a Ti:sapphire laser coupled to a microscope with a programmable x-y stage. While close examination of samples ablated in ambient air revealed persistent defects, a novel modification to the technique by carrying out the ablation under water immersion dramatically reduced the observed defects. In addition to using this technique to create submicron graphene wires, its application to other other 2-D materials, such as hexagonal boron nitride, is detailed.