Ultra-sensitive ethanol detection using a chemiresistive SnO2 thin-film gas sensor functionalized with RuO2
Wonkeun Park1, Yunsung Kang2, Xiaoyan Jin3
1School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
Microsystems & Nanoengineering
|November 6, 2025
Summary
This study developed a novel gas sensor using ruthenium dioxide nanosheets on tin dioxide for enhanced ethanol detection. The sensor shows high sensitivity, selectivity, and stability, making it ideal for breath alcohol monitoring.
Area of Science:
- Materials Science
- Chemical Engineering
- Sensor Technology
Background:
- Tin dioxide (SnO2) thin-film sensors are widely used for gas detection.
- Enhancing the sensitivity and selectivity of SnO2 sensors remains a key challenge.
- Ruthenium dioxide (RuO2) possesses catalytic properties beneficial for gas sensing applications.
Purpose of the Study:
- To design and fabricate a RuO2 nanosheets-functionalized SnO2 thin-film gas sensor.
- To investigate the enhanced ethanol sensing performance of the functionalized sensor.
- To evaluate the sensor's stability, selectivity, and practical applicability for breath alcohol detection.
Main Methods:
- Synthesis of RuO2 nanosheets via intercalation-driven exfoliation.
- Deposition of RuO2 nanosheets onto a sputtered SnO2 thin film.
- Fabrication of a microheater-integrated suspended membrane gas sensor structure.
Main Results:
- The RuO2 nanosheets-functionalized sensor exhibited a 337% increase in response to ethanol compared to pristine SnO2.
- Sensitive ethanol detection was achieved from parts-per-million (ppm) down to parts-per-billion (ppb) levels.
- The sensor demonstrated reliable performance under varied humidity, showed good selectivity, and maintained stability over 28 days.
- Real-time breath alcohol concentration tracking was successfully demonstrated in controlled experiments.
Conclusions:
- RuO2 nanosheets significantly enhance the performance of SnO2 thin-film gas sensors for ethanol detection.
- The developed sensor offers a sensitive, selective, and stable solution for low-power gas sensing.
- The sensor shows high potential for practical applications, including non-invasive breath alcohol monitoring.
