Open‐Bandgap Graphene‐Based Field‐Effect Transistor Using Oligo(phenylene‐ethynylene) Interfacial Chemistry

Organic interfacial compounds (OICs) are required as linkers for the highly stable and efficient immobilization of bioprobes in nanobiosensors using 2D nanomaterials such as graphene. Herein, we first demonstrated the fabrication of a field‐effect transistor (FET) via a microelectromechanical system process after covalent functionalization on large‐scale graphene by introducing oligo(phenylene‐ethynylene)amine (OPE). OPE was compared to various OICs by density functional theory simulations and was confirmed to have a higher binding energy with graphene and a lower band gap than other OICs. OPE can improve the immobilization efficiency of a bioprobe by forming a self‐assembly monolayer via anion‐based reaction. Using this technology, Magainin I‐conjugated OGMFET (MOGMFET) showed a high sensitivity, high selectivity, with a limit of detection of 100 cfu mL−1. These results indicate that the OPE OIC can be applied for stable and comfortable interfacing technology for biosensor fabrication. Amine‐functionalized oligo(phenylene‐ethynylene) (OPE) was introduced as an interface on wafer‐scale graphene in the form of self‐assembled monolayers through anion‐based reaction. The band gap was opened by electron transfer from OPE to graphene via covalent bonding. This property offers high efficiency for graphene‐based transistor applications.