Effects of Frequency and Temperature on the Characteristics of Ceramic Humidity Sensitive Elements

The authers studied the effects of the frequency and temperature on the TiO2-K2OLiZnVO4 ceramic thin film elements' humidity sensing characteristics. During low rh range, the impedance of the elements decreases as the frequency or temperature increases, the humidity sensitivity decreases obviously as the frequency increases or temperature decreases, and platforms appeare at the humidity sensing Characteristic curves. During high rh range, however, the effects of the frequency and temperature can be ignored, and the characteristic curves present excellent linearity. The polarization within the ceramic thin films was analyzed. The polarization causes the insensitivity of micro-capacitance versus rh at low rh and low temperature. Consequently, the mechanism of how the polarization within the ceramics resulted in the effects of frequency and temperature on the elements' characteristics was interpreted in detail.