Synthesis and characterization of Ga2O3/SnO2 thin films via spray deposition for potential gas-sensing applications

Ga₂O₃/SnO₂ thin films were successfully synthesized on glass substrates via spray deposition for potential gas-sensing applications. The structural, optical, and gas-sensing properties of the nanostructured coatings were systematically investigated. UV–Vis–NIR spectroscopy revealed that the incorporation of SnO₂ enhanced the transparency of Ga₂O₃, with the 90:10 wt% Ga₂O₃/SnO₂ sample exhibiting the highest mean transmittance of ∼57% in the UV–Vis range and ∼70% in the NIR region, significantly exceeding that of pure Ga₂O₃. FTIR analysis confirmed the presence of β-Ga₂O₃ vibrational modes, while SEM-EDS showed homogeneous distribution of Sn within the Ga₂O₃ matrix. Ethanol gas-sensing measurements demonstrated that the 90:10 wt% Ga₂O₃/SnO₂ film exhibited a two-fold increase in resistance response at 200 ppm C₂H₅OH compared to pure Ga₂O₃, attributed to enhanced surface depletion and interfacial charge modulation. The results indicate that SnO₂ incorporation improves both optical transparency and gas-sensing performance of Ga₂O₃, making Ga₂O₃/SnO₂ heterostructures promising candidates for UV-transparent, ethanol-selective gas sensors.