An FET-type gas sensor with a sodium ion conducting solid electrolyte for CO2 detection

Abstract

In this paper, a Field-Effect-Transistor (FET)-type gas sensor using the composite of Na2CO3 and NaNO2 as the sensing material is investigated. The sensor has a floating gate (FG) passivated by an insulator stack and a control gate (CG), which are formed in an interdigitated form in a horizontal direction. The inkjet printing process forms the sensing material on the interdigitated FG and CG. Just before forming the sensing material, a (3-aminopropyl) triethoxysilane (APTES) monolayer is formed to prevent diffusionof Na+ ions contained in the sensing material through the insulator layer. The sensor can be electrically programmed like a typical memory device due to the FG, which makes the calibration of the sensor possible. CO2 gas sensing properties of the sensor are characterized at an operating temperature of 160 degrees C. The results indicate that the proposed sensor produces a reasonable and repeatable response to a certain concentration of CO2. (C) 2017 Elsevier B.V. All rights reserved.