Nonlinear pH sensitivity of molecular modified transistors

The integration of organic self-assembled monolayers (SAMs) in electronic devices is very attractive since they offer high flexibility in design and applications. This paper models the operation of functionalized field effect transistor with a liquid gate. The model explains the nonlinear response to pH variations in SAM-field effect devices. The organic monolayers have low density of sites in comparison to inorganic layers; furthermore, the transistor sensitivity to pH is low and dramatically influenced by the Helmholtz capacitance. It was proven that the dissociation constants have a strong effect on the characteristics of organic field effect device.