▎ 摘　　要

The graphene field-effect transistor (GFET) with a thin insulating oxide layer can regulate electrical performance under small voltage. After reactive ion etching of 300 nm SiO2, the substrates with different shapes and thicknesses are used to fabricate GFET. The electrical performance test proves that GFETs with suspended structures have high carrier mobility. Compared with the suspended structures that should uphold voltage within 15 V, a device with SiO2 thickness of 10 nm can achieve superior electrical regulation only within 4 V. The thin insulating oxide layer increases the risk of breakdown. Under the high electric field, the thin oxide layer will be broken down to form a conductive channel, and the interface between graphene and substrate will generate metal-semiconductor contact, forming Schottky-like diode. The electrical properties have changed at this stage. There is an electric current flowing through internal conduction, and the transfer characteristics change from bipolar to unipolar. This research provides a new idea to realize small voltage regulation and a basis for judging graphene transistor failure. (C) 2021 Elsevier B.V. All rights reserved.