Nb2O5, SnO2, and Eu-Doped SnO2 thin film gas sensors: synthesis and characterization

Metal oxide semiconductors (MOSs) are favored for gas sensing due to their high sensitivity, stability, and cost-effectiveness. An enhanced hydrogen detection is demonstrated by synthesizing and characterizing Nb2O5, SnO2, and Eu-doped SnO2 (Eu-SnO2) thin films via RF-PVD to address the limitations of conventional sensors. Their structural characterization reveals an amorphous Nb2O5 phase and a tetragonal crystalline structure for both the SnO2 and Eu-SnO2 films, which exhibit equiaxed grain morphologies. A gas sensing evaluation demonstrates that Nb2O5 only responds at high hydrogen concentrations (10.000 ppm). In contrast, SnO2 and Eu-SnO2 films successfully detect low concentrations of 100 and 50 ppm, respectively. These results confirm the superior potential of SnO2-based films, particularly with Eu doping, for efficient and highly responsive hydrogen gas sensing.