Surface functionalization and porosity studies of high-speed humidity sensors

Presented here are the results of a study on the effects of varying the porosity of unique nanostructured thin films on their humidity sensing properties. Specifically, we look at the capacitive response and the desorption response time of the sensors. It was found that increased porosity tends to decrease the desorption response time and increase the relative humidity where the devices become sensitive. Also presented are the results of surface functionalization effects on device sensitivity. It was found that the dynamic range of the sensors could be attenuated by as much as three orders of magnitude by covalently bonding hydrophobic organic molecules to the surface of the films.