Effect of Sb Doping on Structure and Humidity Sensing Properties of SnO2 Synthesized by Hydrothermal Method

Abstract The tetragonal rutile Sb doped Sn O 2 (0, 0.5, 1 at.%) is successfully synthesized by hydrothermal method. The XRD analysis shows that the average crystallite size of SnO 2 decreases from 29.59 to 20.53 nm with the increase of the doping concentration. SEM images depict the spherical grain morphology of the SnO 2 sample. With the increase of the doping ratio, the optical bandgap value of the SnO 2 samples increases from 3.6 to 3.86 eV and then decreases to 3.47 eV, showing a trend of first increasing and then decreasing. XPS results indicate that oxygen vacancy defects and substitutional defects(Sb Sn )are formed into the SnO 2 lattice, which changes the electronic effect of Sn element to tune the oxygen vacancy concentration. The humidity‐sensitive testing data shows that 1 at.% Sb‐doped SnO 2 humidity sensor presented excellent sensitivity and linearity at a working frequency of 100 Hz as compared to the pure SnO 2 sample.