Abstract: A high-sensitivity field effect transistor using as a channel ultrafine fiber elements such as carbon nanotube, and a biosensor using it. The field effect transistor comprises a substrate, a source electrode and a drain electrode arranged on the substrate, a channel for electrically connecting the source electrode with the drain electrode, and a gate electrode causing polarization due to the movement of free electrons in the substrate. For example, the substrate has a support substrate consisting of semiconductor or metal, a first insulating film formed on a first surface of the support substrate, and a second insulating film formed on a second surface of the support substrate, the source electrode, the drain electrode, and the channel arranged on the first insulating film, the gate electrode disposed on the second insulating film.

Abstract: A high-sensitivity field effect transistor using as a channel ultrafine fiber elements such as carbon nanotube, and a biosensor using it. The field effect transistor comprises a substrate, a source electrode and a drain electrode arranged on the substrate, a channel for electrically connecting the source electrode with the drain electrode, and a gate electrode causing polarization due to the movement of free electrons in the substrate. For example, the substrate has a support substrate consisting of semiconductor or metal, a first insulating film formed on a first surface of the support substrate, and a second insulating film formed on a second surface of the support substrate, the source electrode, the drain electrode, and the channel arranged on the first insulating film, the gate electrode disposed on the second insulating film.