Effects of thickness on the performance of SnO2 gas sensors using low-temperature co-fired ceramic

Abstract

This study develops SnO2-based gas sensors integrated with a low-temperature co-fired ceramic (LTCC) micro hotplate for ethanol detection. SnO2 nanoparticles were synthesized using a simple precipitation method, and sensing layers with varying thicknesses around 0.24 µm, 0.71 µm, and 1.20 µm were applied to evaluate their influence on performance. The results show that the optimal configuration is a 0.71 µm layer, offering high sensitivity, fast response, and efficient recovery. Operating at a low voltage of 3.2 V, the sensors exhibit low power consumption, suitable for portable and battery-operated applications. The gas-sensing mechanism relies on changes in resistance due to interactions between ethanol molecules and oxygen species adsorbed on the SnO2 surface, with the optimal sensor showing superior selectivity for ethanol (C2H5OH) over other gases, including hydrogen sulfide (H2S), ammonia (NH3), acetone (C3H6O), and nitric oxide (NO). The structural and electrical properties of the SnO2 layers, combined with the efficiency of the LTCC micro hotplate platform, contribute to stable sensing performance. This research highlights the importance of thickness optimization to balance sensitivity and response. The proposed sensor offers a low-cost, energy-efficient solution for ethanol monitoring, with potential enhancements through material doping, multi-gas detection, and IoT integration. Copyright (c) 2025 Journal of Metals, Materials and Minerals. This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License https://creativecommons.org/licenses/by-nc-nd/4.0/.