Laser Ablation of Graphene Fundamental Processes and Applications

Front page illustration: SEM image of graphene on silicon dioxide coated silicon wafer. The width of the page corresponds roughly to 30μm. The dark spots are caused by trapped water during wet transfer. The thin lines are folds that are a result of the growth process. i The present report details the results of a fundamental study on laser processing of suspended and supported graphene and the demonstration of high accuracy patterning. For the first time the ablation threshold of graphene was measured. Furthermore, a first investigation on the ablation mechanism of graphene and the influence of substrate has been performed. The results show that graphene ablation is not a purely thermal process, but a complicated process involving many influencing factors. The presence of a substrate has a large influence on the ablation mechanism and will lead to a difference in the thresholds of supported and suspended samples. Laser patterning of graphene with a sub-micron accuracy has been demonstrated, which is an order of magnitude improvement over current attempts. The experimental methods and results will be highly useful in future application of laser patterning. Not only was the minimum energy for successful patterning measured, but also the influence of the substrate was investigated. The patterning experiment has demonstrated the capabilities of laser patterning and its feasibility for industrial applications. ii ii