Effects Of Film Thickness On The Sensitivity Of Tin (IV) Oxide Gas Sensor In Detecting Various Concentrations Of Benzene And Toluene Gases
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Date
2021-07-01
Authors
Teoh, Xuan Chee
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Tin (IV) oxide (SnO2) gas sensor is the most commonly used metal oxide
semiconductor gas sensor in various industries due to its high stability and reliability. In
addition to the experimental works, mathematical models are also important in studying the
responses os the SnO2 gas sensor when it is exposed to a variety of operating conditions and
targeted gases. In the present study, a mathematical model is developed based on Knudsen
diffusion model which is commonly used to describe tha gas diffusion mechanism. Previous
researches had shown that the sensing performance of SnO2 gas sensor is influenced by some
factors, such as operating temperature, targeted gas concentration, film thickness and pore
radius of the sensing film. On top of this, in order to determine the reliability and feasibility of
the develop mathematical model, MATLAB simulation is used to study the effects of targeted
gas (benzene and toluene) concentration (𝐶𝑆
) and film thickness (𝐿) on the sensitivity of the
SnO2 gas sensor (𝑆). From the results obtained, the sensitivity of the gas sensor will increase
with the targeted gas concentration until the maximum adsorption limit is reached. At the same
time, the results showed a lower sensitivity when a thicker sensing film is used. Both of these
results confirmed that the developed mathematical model matches the validity of the theory.
Besides that, SnO2 gas sensor always has a better sensing performance toward toluene than
benzene, which is due to the higher reactivity of toluene as compared to benzene.