SnO2 thin films used as ammonia sensing layers at room temperature

Gas sensors based on the SnO2 thin films were prepared by dip-coating method starting from their corresponding sols. The as-elaborated thin coatings were afterwards annealed at different temperatures during various times. Their morphology, composition and microstructure were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). The results of electrical and sensing measurements indicated that the sensor annealed at 300°C for 3 hours exhibited the best sensitivity towards the detection of NH3 at room temperature