Effect of surface morphology on ionic response of reference field effect transistor

Fabricating reference field effect transistor (FET) sensors instead of reference electrodes are important for the miniaturization and variegated applications of FET sensors. To make a reference FET, the gate surface of FET was modified with the self-assembled monolayer (SAM) of n- octadecyltrimethoxysilane (ODS). Though an ODSSAM FET had low pH-sensitivity, it was cation-sensitive. This work demonstrates the relation between the surface morphology and the cationic and pH-sensitivity of ODS-SAM FETs. A roughness parameter of atomic force microscope images, the mean summit curvature (Ssc) has correlation with the cationic and pH-sensitivity of ODS-SAM FETs.