Hysteresis is a problem in field-effect transistors (FETs) often caused by defects and charge traps inside a gate isolating (e.g., SiO2) layer. This work shows that graphene-based FETs also exhibit hysteresis due to water physisorbed on top of graphene determined by the relative humidity level, which naturally happens in biosensors and ambient operating sensors. The hysteresis effect is explained by trapping of electrons by physisorbed water, and it is shown that this hysteresis can be suppressed using short pulses of alternating gate voltages.

We acknowledge the support by the Grant Agency of the Czech Republic (grant No. 17-21413S) and H2020 Twinning programme (project SINNCE, 810626), and MEYS CR (project No. LQ1601 – CEITEC 2020). We also acknowledge the CEITEC Nano Research Infrastructure supported by MEYS CR within the Project LM2015041 for providing us with access to their facilities, and Miroslav Kolíbal for reading the manuscript of this text.