Membrane Selectivity versus Sensor Response in Hydrogenated Amorphous Silicon CHEMFETs Using a Semi-Empirical Model

Abstract

Toxic amides, such as acrylamide, are potentially harmful to Human health, so there is great interest in the fabrication of compact and economical devices to measure their concentration in food products and effluents. The CHEmically Modified Field Effect Transistor (CHEMFET) based onamorphous silicon technology is a candidate for this type of application due to its low fabrication cost. In this article we have used a semi-empirical modelof the device to predict its performance in a solution of interfering ions. The actual semiconductor unit of the sensor was fabricated by the PECVD technique in the top gate configuration. The CHEMFET simulation was performed based on the experimental current voltage curves of the semiconductor unit and on an empirical model of the polymeric membrane. Results presented here are useful for selection and design of CHEMFET membranes and provide an idea of the limitations of the amorphous CHEMFET device. In addition to the economical advantage, the small size of this prototype means it is appropriate for in situ operation and integration in a sensor array.

Can Graphene Bilayers Be the Membrane Mimetic Materials? Ion Channels in Graphene-Based Nanostructures

“…ION CHANNELS... transport, sensing properties and changing of the sensor electric parameters are synchronized and interdependent. By the way, for all chemicallyselective field-effect transistors (ChemFET), and particularly for the ion-selective fieldeffect transistors (ISFET) [79,80], there is no difference between the "membrane selectivity" and the "sensor electric response specificity" [81]. In recent years the ion sensing functions in microfluidic and even nanofluidic chemometric systems (labs-on-a-chip) are performed by the ionic transistors based on the ion concentration polarization by an ion exchange membrane [82], capable of performing electrogenic ion exchange and sensing with the electric response.…”