Magnetic-field-modulated H2S sensing performance of CVD-grown CuO/Cu2O

Magnetic-field-assisted modulation of charge transport offers a promising pathway to enhance the performance of metal–oxide–semiconductor gas sensors without altering material composition or device architecture. In this work, a mixed-phase CuO/Cu2O nanostructure layer is grown over SiO2/Si substrates via chemical vapor deposition for H2S sensing at room temperature. Structural and spectroscopic analyses confirm the coexistence of Cu2+ and Cu+ states, leading to the formation of a p–p heterojunction. The effect of an externally applied perpendicular magnetic field on electrical transport and sensing characteristics was systematically investigated. The sensor exhibits an enhancement in response from ∼9% to ∼43% toward 10 ppm H2S under a magnetic field, an approximately 4.8-fold improvement compared to without applying a magnetic field. This enhancement is attributed to magnetic-field-induced modulation of carrier dynamics, including Lorentz-force-driven carrier redistribution, reduced effective mobility, and increased interfacial barrier height, along with improved oxygen adsorption kinetics. The combined effects lead to amplified resistance modulation upon gas exposure. These findings demonstrate that magnetic-field-assisted tuning provides an efficient and low-energy strategy to significantly enhance sensitivity and selectivity in oxide-based gas sensors, offering new insights into magneto-transport-coupled sensing mechanisms.