Electron-interfered field-effect transistors as a sensing platform for detecting a delicate surface chemical reaction

Abstract

We introduce a new electron-interfered field-effect transistor (EIFET) device with a modified organic charge-modulated FET (OCMFET) structure and demonstrate its ability to detect the surface chemical reaction degree (or rate). When the electrodes used as the control gate (G) and floating G in the OCMFET were changed to the sensing area and voltage-applied electrode, respectively, the threshold voltage (V-th) of the EIFET varies sensitively with the progression of the surface reaction on the control G. Here, the control G is newly referred to as the interference electrode (IE). The results indicate that variations in dV(th)/dt in the EIFET coincide almost exactly with the variations in its surface energy (gamma(s)) after dropping thiol solutions onto the IE, as the model reactive materials are capable of surface reaction with a novel metal. We argue that the surface reaction of IE with TP molecules induces variations in V(th)s and suggest that this phenomenon occurs because some of the electrons released during the reaction process accumulate inside the IE and interfere with the primary V-G, thereby partially canceling the applied V-G. Although this study is somewhat lacking in terms of analysis and interpretation, it demonstrates the potential of our newly designed EIFET device to quantify surface chemical reactions.