This thesis builds new graphene chemical and biological sensing technologies from the ground up by developing device models, systems, and applications. On the modeling side, this thesis develops a DC model for graphene electrolyte-gated field-effect transistors (EGFETs). It also presents a novel frequency-dependent (AC) small-signal model for graphene EGFETs and demonstrates the ability of these devices to operate as functional amplifiers for the first time.
Graphene sensors are transitioned to the system-level by developing a new sensor array architecture in conjunction with a compact and easy-to-use custom data acquisition system. The system allows for simultaneous characterization of hundreds of sensors and provides insight into graphene EGFET performance variations. The system is adapted to develop solution-phase ionized calcium sensors that have been functionalized using a polyvinyl chloride (PVC) membrane containing a neutral calcium ionophore. Finally, the sensor system is employed to develop gas-phase chemiresistive ammonia sensors that have been functionalized using cobalt porphyrin.
Thesis Supervisor: Prof. Tomás Palacios