Gravimetric humidity sensor based on ZnO nanorods covered piezoresistive Si microcantilever

A ZnO nanorods film covered silicon resonant cantilever sensor is developed for atmosphere humidity detection by monitoring the resonant frequency shifts induced by the additional weight of adsorbed water molecules. Two different crystalline seed-layer deposition methods were applied to grow different nanorods films. The morphology of the ZnO films were characterized and the sensor sensitivities were measured under different relative humidity (RH) levels. The experiments results showed that this novel humidity sensor with ZnO nanorods has a sensitivity of 101.5 +/- 12.0 ppm/RH% (amount of adsorbed water of 36.9 +/- 4.4 ng/RH%), indicating its potential for portable sensing applications.