Kinetic Water Sorption by Porous Silicon Layers and Temporal Response of Moisture Sensors
Résumé
The experimental results obtained for kinetic water sorption by porous silicon (PS) layers and temporal response of moisture sensors based on these PS layers are presented in this paper. We studied two PS layers presenting equal porosity of 45 %, but differing in their nanostructure organization. PS1 presents a specific area of 330 m²/g and PS2 presents a specific area of 223 m²/g. We made resistive sensors deposing metallic contacts on PS layers surface; we measured the resistance variation of PS layers versus moisture level. The main result consists in the difference of time constant between kinetic water sorption and sensors temporal response. We represented the temporal response of kinetic water sorption which very longer than the temporal response of PS sensors. These results seem to confirm that mechanisms involved in sensors works occur at the PS layers surface; which is precious information in understanding of sensors functioning.