Biosensor based on heterojunction bipolar transistor

A method for sensing a target analyte in an aqueous solution, the method comprising:

• providing a heterojunction bipolar transistor, the heterojunction bipolar transistor comprising:
• a semiconductor emitter formed from a first semiconductor material and including an emitter electrode for connecting to an emitter voltage;
• a semiconductor collector including a collector electrode for connecting to a collector voltage;
• and
• a semiconductor base formed from a second semiconductor material that is different from the first semiconductor material and positioned between the semiconductor emitter and the semiconductor collector;
• providing a sensing surface, external to the heterojunction bipolar transistor, the sensing surface comprising:
• a conducting film;
• and
• a reference electrode;
• and
• providing an extended base component coupling a bond pad on an exterior surface of the heterojunction bipolar transistor to the sensing surface, wherein the extended base component comprises a metallic conducting wire;
• and
• immersing the sensing surface in the aqueous solution.

A sensor, comprising:

• a heterojunction bipolar transistor, comprising:
• a semiconductor collector including a collector electrode for connecting to a collector voltage;
• a semiconductor base disposed on the semiconductor collector and coupled to an extended base component, wherein the semiconductor base is formed from a first semiconductor material;
• and
• a semiconductor emitter disposed on the semiconductor base and including an emitter electrode for connecting to an emitter voltage, wherein the semiconductor emitter is formed from a second semiconductor material different from the first semiconductor material;
• a sensing surface, external to the heterojunction bipolar transistor;
• and
• to the extended base component connecting a bond pad on an exterior surface of the heterojunction bipolar transistor to the sensing surface, wherein the extended base component comprises:
• a metallic conducting wire.