Capacitive humidity-sensing properties of ZnO nanorods/silicon nanoporous pillar array enhanced by LiCl incorporation

Humidity sensors are playing more and more important roles in the fields of modern industry, agriculture, food production and storage, medicine as well as in our daily life. To satisfy the increasing technical requirements such as high sensitivity, short response and recovery time and measurement reproducibility, much effort has been devoted to developing novel sensing materials. In recent years, nanocomposite humidity-sensing materials have aroused much attention because of their high performances. In the paper, we report the preparation and capacitive humidity-sensing properties of a ZnO nanorod bundling array grown on silicon nanoporous pillar array (ZnO/Si-NPA), and those of a LiCl-incorporated ZnO/Si-NPA (LiCl: ZnO/Si-NPA). It was demonstrated that compared with ZnO/Si-NPA, the integral humidity sensing properties of LiCl: ZnO/Si-NPA were promoted significantly. The underlying mechanism was probed by measuring and analyzing the behavior of the capacitance variation with frequency at different RH levels. These results demonstrated that LiCl: ZnO/Si-NPA might be a promising material system for fabricating humidity sensors with high-performances.