Abstract
This study reports an approach to implement a capacitive type relative-humidity sensor (RH sensor) with sensing electrodes embedded in dual-layer nanoporous anodic aluminum oxide (np-AAO). Based on the superior material properties of np-AAO, the dielectric constant change of np-AAO will lead sensing capacitance change after moisture absorbing. The present RH sensors has two merits, (1) dual-layer np-AAO will increase the area for moister absorbing, (2) the electric field of embedded sensing electrodes will pass through both top and bottom np-AAO layers to increase the sensing signals. Measurement results show that the sensitivity is improved for near 4-fold by the present design at the sensing range of 30%RH to 95%RH. © 2013 IEEE.