Deposition of CeOx/SnOx-based thin films via RF magnetron sputtering for resistive gas sensing applications

Cerium oxide-tin oxide (CeO x /SnO x ) thin films with varying Sn content were deposited using RF magnetron sputtering and investigated for hydrogen sensing applications. Structural, compositional, and morphological properties were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Gas sensing measurements showed effective hydrogen detection at room temperature, with the sensitivity strongly influenced by Sn content and oxygen vacancy concentration. Higher Sn concentration enhanced the sensing response, which was correlated with microstructural features obtained from AFM and EDX, as well as with the presence of Ce 3+ and Ce 4+ oxidation states identified by XPS. This study highlights the potential of CeO x /SnO x thin films for possible back-end-of-line integration and provides proof-of-principle for room-temperature hydrogen sensing.