Field-effect transistor, single electron transistor, and sensor using same
A sensor for detecting a substance to be detected. The sensor includes a field-effect transistor (1A) having a substrate (2), a source electrode (4) and a drain electrode (5) both installed on the substrate (2), and a channel (6) to serve as a current path between the source electrode (4) and the drain electrode (5). The field-effect transistor (1A) further includes an interaction sensing gate (9) for immobilizing a specific substance (10) interactive selectively with the substance to be detected and a gate (7) to which a voltage is applied so that the interaction is detected as a characteristic variation of the field-effect transistor (1A). Such a structure enables a sensor to detect a substance to be detected with a high detection sensitivity.