The improvement study of model for humidity sensor based on quartz glass

This paper analyzes the 20 percent Sn 4+ -doped titania films who were prepared on the quartz glass humidity sensor by complex impedance analysis, improves the equivalent circuit model whose circuit description code is R(C(R(RC))). This equivalent circuit uses the constant phase angle element Q instead of the capacitance C in the second resistance-capacitance parallel entries, and its circuit description code is R(C(R (RQ))). The results show that the model is more reasonable, because the error is smaller when it is used to fit the impedance spectra of the sensor. The equivalent circuit is convenient for analyzing the diffusion information of the thin films because of the changes of the value of n.