▎ 摘　　要

The unique band structure of graphene makes the gate leakage current in a graphene field-effect transistor (FET) different from that in silicon FET. Theoretical investigation in this letter demonstrates that the Fowler-Nordheim tunneling current (TC) in a graphene FET is different from that in a silicon FET. Numerical calculations show that a higher oxide electric field results in larger TC in a graphene FET than that in a silicon FET. This implies that, to ensure a workable graphene FET, a thicker gate oxide is needed to limit the gate leakage current compared to that for a silicon FET.