Vertical Split Gate T‐Shaped Tunneling Field‐Effect Transistor Based pH Sensor for Charged and Neutral Biomolecules Detection in Low Concentration of Electrolyte

This manuscript investigates the pH detecting capabilities of a split‐gate, step‐channel ion‐sensitive vertically T‐shaped tunneling field‐effect transistor (SC‐IS‐VTFET) biosensor containing a charge sheet. The pH model is designed to assess the variation in potential drop resulting from changes in the electrolyte's pH. The pH model computes the density of states as a function of pH for the electrolyte solution. Since the intrinsic semiconductor and the electrolyte solution are comparable, the electrolyte has been characterized by altering the intrinsic semiconductor's properties. While thermally produced mobility carriers (holes and electrons) are present in intrinsic semiconductor material, mobile ions are present in solutions of ions (electrolytes). These holes, along with electrons, stand in for the solution's mobile ions. The surface charge density at the oxide‐silicon interface of the proposed vertical TFET pH biosensor was determined using modeling based on physics. The proposed device shows the impact of pH variation on its electrical attributes, such as threshold voltage , drain current , sensitivity regarding voltage ( S V ), and current ( S I ). The pH‐based SC‐IS‐VTFET sensor exhibits a drain current sensitivity of 3.2 × 10 8 with a cavity length of 30 nm.