Reduction of Current-Voltage Hysteresis in Graphene Field Effect Transistor Achieved with Dry Transfer Using Flexible Tape Supporter*

In the conventional wet transfer method of Chemical Vapor Deposition (CVD) graphene, it is inevitable to have water molecules trapped between graphene and substrate. The trapped water molecules can cause the hysteretic behavior in current-voltage curves of graphene field effect transistor (GFET). Here, a new dry transfer method adopting the Kapton tape as an additional flexible supporting layer is demonstrated. The N₂ blowing and heating processes are added to vaporize the water molecules adsorbed on graphene layer right before the transfer step. By comparing the I-V characteristics of wet- and dry-transferred GFET, the field effect mobility is found to be larger for the dry-transfer GFET in comparison with the wet-transferred one, possibly due to the more uniform Coulomb potential landscape. Also, the hysteretic behavior is found to be reduced substantially in accordance with the decrease of trapped water molecules. The obtained electron field effect mobilities are ~1118 cm²/Vs and ~415 cm²/Vs for dry- and wet-transferred graphene, respectively. Our dry transfer method can provide a simple and reliable way to transfer the CVD graphene onto an arbitrary substrate with its as-grown electrical properties being preserved, regardless of the substrate size.