| Abstract
| - The effect of chemical surface treatment on the sensitivity, specificity, and stability of mesoporous Sithin film vapor sensors is studied. The vapor sensors operate by measurement of Fabry−Pérot interferencefrom the porous Si layer, probed using a diode laser operating at a wavelength of 687 nm. Four chemicallydistinct surface types are each probed with three different analyte vapors: ethanol, methyl ethyl ketone,and n-hexane, all in a carrier gas of pure nitrogen. The four different surface types include the H-terminated,freshly etched material (Si−H), ozone-treated material (Si-ozone), electrochemically methylated material(Si−CH3), and thermally oxidized samples (Si−O−Si). Surface modification has a pronounced effect onthe specificity and stability. It is found that the Si−H material is more sensitive to the hydrophobic analyterelative to either the Si−O−Si or Si-ozone samples. Similarly, the Si−CH3 material is more sensitive tothe more hydrophobic analyte, although it is found to be much more stable than the Si−H material.
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