Direct patterning of nitrogen-doped chemical vapor deposited graphene-based microstructures for charge carrier measurements employing femtosecond laser ablation

摘要

Chemical vapor deposited nitrogen-doped graphene, transferred onto a SiO2/Si substrate, was selectively patterned by femtosecond laser ablation for the formation of the topology dedicated to charge carrier measurements. Ultrashort 1030nm wavelength Yb:KGW fs-laser pulses of 22 mu J energy,14 mJ cm(-2) fluence, 96% pulse overlap, and a scanning speed of 100mm s(-1), were found to be the optimum regime for the high throughput microstructure ablation in graphene, without surface damage of the substrate in the employed fs-laser micromachining workstation. Optical scanning electron and atomic force microscopy, as well as Raman spectroscopy, were applied to clarify the intensive fs-laser light irradiation effects on graphene and the substrate, and to also verify the quality of the graphene removal. Measurements of magnetotransport properties of the fs-laser ablated nitrogen-doped graphene microstructure in the Hall configuration enabled the determination of the type, as well as concentration of charge carriers in a wide range of temperatures.