Structural and capacitive humidity sensing properties of nanocrystal magnetite/silicon nanoporous pillar array

A composite thin film was fabricated by coating nanocrystal magnetite (nc-Fe3O4) on silicon nanoporous pillar array (Si-NPA), which shows a regular hierarchical structure composed by the pillar array in micron dimension and the nanoporous structure in the film of Fe3O4. Capacitive humidity sensors were made based on nc-Fe3O4/Si-NPA and the corresponding sensing properties were investigated. The experimental results disclosed that nc-Fe3O4/Si-NPA sensor exhibits high sensitivity, strong output signal intensity, and short response times. These high performances of nc-Fe3O4/Si-NPA sensor are explained on the basis of the structural and compositional factors of nc-Fe3O4/Si-NPA.