Mechanism of flexural resonance frequency shift of a piezoelectric microcantilever sensor during humidity detection

We have examined the flexural resonance frequency shift of a piezoelectric microcantilever sensor (PEMS) during humidity detection and have shown that the flexural resonance frequency shift of the PEMS during detection was a result of Young's modulus change of its piezoelectric layer. Because of the piezoelectric layer's Young's modulus change, the PEMS flexural resonance frequency shift was more than 300 times larger than could be accounted for by mass loading.