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Updated: May 11, 2026

Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
Published on: March 22, 2019
A physicochemical mechanism of chemical gas sensors using an AC analysis
Jaehyun Moon1, Jin-Ah Park, Su-Jae Lee
1OLED Research Center, Electronics and Telecommunications Research Institute, Daejeon 305-350, Korea. jmoon@etri.re.kr
Abstract:
Electrical modeling of the chemical gas sensors was successfully applied to TiO2 nanofiber gas sensors by developing an equivalent circuit model where the junction capacitance as well as the resistance can be separated from the comparable stray capacitance. The Schottky junction impedance exhibited a characteristic skewed arc described by a Cole-Davidson function, and the variation of the fit and derived parameters with temperature, bias, and NO2 gas concentration indicated definitely a physicochemical sensing mechanism based on the Pt|TiO2 Schottky junctions against the conventional supposition of the enhanced sensitivity in nanostructured gas sensors with high grain boundary/surface area. Analysis on a model Pt|TiO2|Pt structure also confirmed the characteristic impedance response of TiO2 nanofiber sensors.
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