TP21 - Optimizing AC Excitation Frequency for Linear Complex Impedance Response in Metal Oxide Semiconductor Gas Sensing
- Event
- EUROSENSORS XXXVII
2025-09-07 - 2025-09-10
Wroclaw - Band
- Poster II
- Chapter
- Bio/chemical and Environmental Sensors
- Author(s)
- H. A. Imran, O. Brieger, C. Bur, A. Schütze - Lab for Measurement Technology Saarland University, Saarbruecken (Germany)
- Pages
- 391 - 392
- DOI
- 10.5162/EUROSENSORS2025/TP21
- ISBN
- 978-3-910600-07-2
- Price
- free
Abstract
Metal Oxide Semiconductor (MOS) gas sensors are of high interest in gas detection applications due totheir high sensitivity and low cost. However, conventional read-out methods based on resistive measurements oftenexhibit a highly nonlinear response to gas concentration, limiting their effectiveness for accurate quantification.In this study, we present an alternative approach that leverages impedance spectroscopy to identify an optimalexcitation frequency at which the imaginary component of the impedance (Z′′) exhibits a highly linear correlationwith gas concentration. As a case study, we evaluate the AS-MLV-P₂ sensor under varying concentrations of ethanolgas. The proposed method demonstrates strong linearity, achieving an R₂ value of 98.26 % for a linear fit betweenthe mean of Z′′ over 35 frequency sweeps and Ethanol concentrations ranging from 10⁰⁰ ppb to 8000 ppb, at anexcitation frequency of 3.568 MHz.