Capacitive humidity sensors based on the dielectrophoretically manipulated ZnO nanorods

In this paper, the capacitive relative humidity sensors based on dielectrophoretically manipulated ZnO nanostructure were constructed and studied. The humidity-sensitive ZnO nanorods were first synthesized by the thermal decomposition technique and deposited among the micromachined electrodes pairs via dielectrophoretic manipulation. The manipulated samples were detected as the capacitive sensors in which the nanostructured ZnO acted as the sensing elements. The capacitive humidity sensors were constructed by detecting the variations of the ZnO dielectric constant changing with the humidity environment. The results showed that the sensor had high humidity sensitivity, good stability, fast response/recovery time and well reproducibility. The dielectrophoresis manipulation can also improve the sensitivity of the sensor efficiently.