  The aim of this study is to assess femtosecond laser patterning of graphene
in air and in vacuum for the application as source and drain electrodes in
thin-film transistors (TFTs). The analysis of the laser-patterned graphene with
scanning electron microscopy, atomic force microscopy and Raman spectroscopy
showed that processing in vacuum leads to less debris formation and thus
re-deposited carbonaceous material on the sample compared to laser processing
in air. It was found that the debris reduction due to patterning in vacuum
improves the TFT characteristics significantly. Hysteresis disappears, the
mobility is enhanced by an order of magnitude and the subthreshold swing is
reduced from $S_{sub}~=~2.5~\mbox{V/dec}$ to $S_{sub}~=~1.5~\mbox{V/dec}$.
