Graphene bandgap induced by ferroelectric HfO₂ doped with Zr (HfZrO)

Motivated by the need to open a bandgap in graphene, we show experimentally that the CMOS-compatible ferroelectric HfZrO substrate induces a bandgap of 0.18 eV in graphene monolayer, which allows top-gate graphene/HfZrO/SiO₂/Si field-effect transistors to have high on/off current ratio, of about 10³, at small drain voltages, of 0.5 V, and for gate voltage spans of only 3.5 V. In addition, these transistors have a very high transconductance, of about 1 mS, and carrier mobilities of 7900 cm² Vs^-1. The results show that this relatively simple and wafer-scale compatible bandgap opening method in graphene renders this material useful for digital low-power electronics.