Reprint of: Improvements on thermal stability of graphene and top gate graphene transistors by Ar annealing

Thermal annealing of graphene was studied to improve the thermal stability. During the annealing under an Ar atmosphere with temperature from 100 °C to 600 °C, graphene exhibits partial removal of PMMA residues, low density of defect cracks in SEM images and relatively low ID/IG ratios in Raman spectrum probing. For a top-gated graphene transistor with thermal annealing, it performs high carrier mobility up to 3500 cm2 V−1 s−1 and slightly asymmetric bipolar behaviours as well as slight Dirac point variation within ±0.2 V.