Charge detector and process for sensing a charged analyte

A charge detector for operating a dual gate field effect transistor at a quantum capacitance limit to perform ultrasensitive biosensing, the charge detector comprising:

• a charge sensor that senses a charged analyte and produces a charge signal in response to contact with the charged analyte, the charge sensor comprising an electrical circuit that comprises:
• a sensing electrode in communication with a transducer and that produces the charge signal;
• and
• a reference electrode by which sensing electrode is electrically referenced and that receives a reference potential;
• the transducer in electrical communication with the charge sensor and that:
• receives the charge signal from the charge sensor;
• receives a feedback control signal;
• and
• produces a transduction signal in response to receipt of the charge signal and the feedback control signal, the transducer comprising:
• an adder in electrical communication with the charge sensor and that:
• receives the charge signal;
• receives a gate voltage;
• and produces a sum voltage from the charge signal and the gate voltage;
• and
• the dual gate field effect transistor in electrical communication with the adder and that:
• receives the sum voltage from the adder;
• receives a drain voltage;
• receives the feedback control signal from a sensitivity controller;
• and produces the transduction signal from the sum voltage, the drain voltage, and the feedback control signal;
• the dual gate field effect transistor comprising:
• an analyte gate;
• a two-dimensional active layer disposed on the analyte gate;
• a source electrode disposed on the two-dimensional active layer and in electrical communication with the two-dimensional active layer,
• a drain electrode disposed on the two-dimensional active layer and in electrical communication with the two-dimensional active layer and in electrical communication with the source electrode via the two-dimensional active layer;
• and
• a control gate disposed on the two-dimensional active layer and controlling the communication of electrical current in the two-dimensional active layer between the source electrode and the drain electrode,
• such that the sensing electrode and the reference electrode of the charge sensor are different structural elements than the analyte gate, the two-dimensional active layer, the source electrode, the drain electrode, and the control gate of the dual gate field effect transistor,
• wherein the electrical current communicated in the two-dimensional active layer is changed in response to a change the sum voltage due to a change in a presence of the charged analyte at the sensing electrode;
• and
• the sensitivity controller in electrical communication with the transducer and that:
• receives the transduction signal from the transducer;
• produces the feedback control signal in response to receipt of the transduction signal from the transducer;
• and
• produces a charge readout in response to receipt of the transduction signal from the transducer.