Robust graphene field-effect transistor biosensors via hydrophobization of SiO₂ substrates

Abstract The interfacial adhesion energy between graphene and underlying substrates is considerably important for robust graphene biosensors because water molecules can intercalate underneath graphene when submerged, possibly detaching graphene from substrates. This study investigated the robustness of graphene field-effect transistor arrays fabricated on hydrophobic and hydrophilic SiO2 substrates. Although the graphene sheets delaminated from hydrophilic substrates within minutes of submersion in a buffer solution, they remained stable on hydrophobic substrates for several days. This result agreed with the estimated thermodynamic work of adhesion in water, which improved significantly from -17.3 to 17.7 mJ/m2 through the hydrophobization process of the substrates.