Low-voltage graphene field-effect transistors based on octadecylphosphonic acid modified solution-processed high-k dielectrics

In this study, a solution-processed bilayer high-k dielectric (Al₂O _y /TiO _x , abbrev. as ATO) was used to realize the low-voltage operation of graphene field-effect transistors (GFETs), in which the graphene was grown by atmospheric pressure chemical vapor deposition (APCVD). Upon modifying the interface between graphene and the dielectric by octadecylphosphonic acid (ODPA), outstanding room-temperature hole mobility up to 5805 cm² V^-1 s^-1 and electron mobility of 3232 cm² V^-1 s^-1 were obtained in a small gate voltage range from -3.0 V to 3.0 V under a vacuum. Meanwhile, an excellent on/off current ratio of about 8 was achieved. Our studies demonstrate an effective route in which utilizing the low-temperature solution-processed dielectrics can achieve low-voltage and high performance GFETs.