Laser-processed rapid fabrication of FET devices with large-scale chemically grown graphene

Graphene field-effect transistors (FETs) are promising candidates for next-generation electronic devices due to their exceptional electrical properties. This study presents the fabrication and transport characteristics of graphene FETs patterned via a novel mask-free technique using a general-purpose femtosecond laser beam cutter. This method enables precise patterning while causing no damage to graphene, except at the cutting edge. Furthermore, contamination from polymer residues, commonly introduced in traditional lithographic processes, is entirely eliminated. Another significant advantage is the extremely short fabrication time. The charge neutrality point (CNP), which had been strongly shifted to higher gate voltages due to unintentional p-type doping, was substantially lowered by current-induced cleaning. Temperature-dependent conductance and magnetoresistance (MR) measurements are presented. Negative MR behavior was analyzed using weak localization theory, allowing extraction of scattering lengths, which were compared with values reported in previous studies. These results contribute to a deeper understanding of charge transport and scattering mechanisms in graphene. This study demonstrates that femtosecond laser processing is an efficient approach for fabricating high-performance graphene FETs. The proposed fabrication technique is readily applicable to other two-dimensional materials.