Interface Surface Effect of SnO₂–GO Thin-Film Heterostructure on H₂ Gas Sensor Performance

The use of metal oxide–graphene oxide (GO) multilayer heterostructure junctions is an efficient technique to enhance the performance of gas sensors owing to the greater number of charge carriers that accumulate in the interface region. Thin film of pristine GO and SnO₂ and multilayer GO–SnO₂ and SnO₂–GO heterostructures were deposited by a spray pyrolysis technique on glass substrates for H₂ gas sensor applications. The as-deposited pristine and multilayer heterostructure thin films were characterized by glancing angle X-ray diffraction (GAXRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), ultraviolet–visible spectroscopy (UV–vis), micro-Raman spectroscopy, and contact angle techniques to confirm their structural, surface, optical, and functional group properties. The heterostructure thin-film-based gas sensors exhibited enhanced gas sensitivity compared to the pristine thin-film-based sensors. Notably, the SnO₂–GO heterostructure thin-film-based sensor device showed a better gas response of 112%, with response/recovery times of 66.4 s/​74 s, toward H₂ gas detection. The results of the present study indicate that the heterostructure-based multi-charge-transfer process is an effective way to improve the H₂ gas sensor performance of thin films.