Dresden 2020 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 37: Focus Session: Functional Metal Oxides for Novel Applications and Devices II (joint session HL/DS)

DS 37.1: Hauptvortrag

Donnerstag, 19. März 2020, 09:30–10:00, POT 81

Basics of Gas Sensing with Semiconducting Metal Oxides — •Nicolae Barsan — University of Tuebingen, Tuebingen, Germany

This contribution will present the basic knowledge needed to understand gas sensing with semiconducting metal oxides. It will explain how the interaction with atmospheric gases changes both surface charge and free charge carriers concentration and will descrice that in terms of reception and transduction functions. The body of essential data needed for the understanding of sensing for the case of two representative oxides, namely SnO2 and WO3 will be presented together with the description of the most relevant operando investigation techniques, namely Kelvin probe work function changes measurements and Diffuse Reflectance Infrared Fourier Transform Spectroscopy.The example of CO detection in the presence of humidity will be in the focus. It will be shown how this knowledge can be formalized with the help of the quasi-chemical reactions. Furthermore it will be explained how the charging of the surface changes the properties of the oxide and how this can be quantified with the help of the Poisson and electro-neutrality equations for both n and p-type materials.