Wang, H., Xu, L., Chen, W., Wee, K. P. X., Kong, A., Md Husni, M. H. K., Gu, Z., Ho, C. P., Zhang, Q., & Ng, D. K. T. (2026). NH3 and SF6 detection based on long-wave infrared pyroelectric detector. In W. Piyawattanametha, Y.-H. Park, & H. Zappe (Eds.), MOEMS and Miniaturized Systems XXV (p. 12). SPIE. https://doi.org/10.1117/12.3080394
Abstract:
Thermal infrared emitter and pyroelectric detector are two common main components to provide effective gas detection in non-dispersive infrared (NDIR) sensor. Commercially available emitters often have low emission power above 5 μm, limiting gas sensing in the long-wave infrared (LWIR), including ammonia (NH3) and sulfur hexafluoride (SF6). In this work, we make use of an in-house scandium aluminum nitride (ScAlN) pyroelectric detector with high absorption of ~85% in the wavelength range from 10.5 to 11 μm to compensate for the low emitter power at the system level. The pyroelectric detector based NDIR sensor demonstrates reliable gas responses for both NH3 and SF6, with the detection limit of 44 and 6 ppm respectively. The relatively higher detection limit of NH3 is due to its weak infrared absorption. To further investigate this, we demonstrate sensors using 10 cm and 20 cm long gas channel paths. When the gas path length is 20 cm, the system achieves a detection limit of 19 ppm, significantly improved compared to 44 ppm with 10 cm gas path length. The effective absorption coefficient of NH3 is calculated to be ~0.025 based on the modified Beer-Lambert law, indicating strong sensing capability. This pyroelectric detector-based gas sensor shows great potential for real-time SF6 leak detection in industrial processes, as well as NH3 monitoring in clean energy.
License type:
Publisher Copyright
Funding Info:
This research / project is supported by the National Research Foundation - Low Carbon Energy Research (LCER) Phase 2
Grant Reference no. : U2303D4001
Description:
Copyright 2026 Society of Photo‑Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, and modification of the contents of the publication are prohibited.