Design of a micro-Raman spectroscopy chamber for operando studies on semiconductor gas sensors

This work outlines the design and validation of an ambient chamber specifically tailored for confocal micro-Raman spectroscopy investigations on semiconductor gas sensors under operando conditions. The system enables real-time analysis of gas–solid interactions providing a reproducible and versatile platform for the characterization of a wide range of gas-sensing devices. A comprehensive study was carried out, covering chamber design, 3D modeling, integration with a custom data acquisition system, residence time distribution analysis for fluid dynamics assessment, temperature and humidity monitoring. Finally, the system was validated using an indium oxide-based sensor exposed to ethanol. The proposed gas-sensing setup is designed to be easy to fabricate, operate, and maintain. It supports solid-state gas sensors with sub-millimeter active areas and can operate at temperatures up to 500 °C achieving high-resolution spectroscopic measurements. Furthermore, its modular architecture ensures seamless integration with various microscopy platforms, enhancing the quality and flexibility of spectral acquisition.