Design and simulation of carbon nanotube hybridized field effect transistor biopotential sensor

Standard biopotential electrodes in clinical applications, require the use of electrolytic gel and skin abrasion for better electrical interface between electrode and skin. Although the pre-gelled skin electrodes present good performance for short duration measurements, signal deterioration occurs on long-duration records, since the gel dries out over a period of time. The gel may also cause skin irritation or allergic reactions. Gel-free dry electrodes are a promising alternative for long-duration recordings. However, high contact impedance, high interface potential, and low signal quality problems appear in dry electrodes. This thesis aims to design a novel carbon nanotube and metal oxide semiconductor field effect transistor based dry electrode to measure biopotentials on the human skin with high signal-to-noise ratio. The vertically aligned multiwalled carbon nanotube arrays are grown on the gate terminal of the the transistor. The multiwalled carbon nanotubes penetrate the outer layer of the skin at the microscales. This penetration eliminates the high impedance and noise effects of electrode-skin contact. The simulation results demonstrate and prove the efficiency of the proposed electrode