Investigations on humidity sensing of nanostructured tin oxide synthesised via mechanochemical method

摘要

In this article, nanocrystalline tin oxide powder was prepared by a mechanochemical method. The synthesised powder was characterised using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD shows the crystalline nature of the synthesised material. The crystallite size was estimated using Debye–Scherrer equation and its minimum value was 9?nm. Surface morphologies of the sensing pellets were investigated using SEM. Pellets as well as thick films were used as sensing elements for humidity sensing measurement. Thick film was prepared on alumina substrate using screen printing technique. Solid-state pellets as well as films were subjected to humidity-sensing measurements in a specially designed humidity chamber. Variations in resistance with relative humidity (%RH) were measured. The effects of annealing on the surface morphologies as well as on the sensitivity of the sensor were also investigated. Hysteresis and ageing effects on experimental results were found 60% and 64%, respectively, for the sensing element prepared after annealing at 600°C.