Comparison of sensitivities of carbon nanotube field-effect transistor biosensors with and without top metal gate

Abstract

The sensitivities of biosensors using top-gate-type carbon nanotube field-effect transistors (CNT-FETs) with and without a top metal gate were compared. The CNT-FET biosensor without the top metal gate (sensor I) showed about three times higher transconductance than the one with the top metal gate (sensor II) when they were modulated by a reference gate electrode placed in a solution. Further, the sensitivity of sensor I was three times higher than sensor II. These results were attributed to the shielding effect of the top metal gate electrode placed in the solution, which was proved by a numerical simulation.