Novel Design of Porous Silicon Based Sensor for Reliable and Feasible Chemical Gas Vapor Detection

In this study, an innovative design for porous silicon (PSi) based sensors is proposed to eliminate some problems of conventional PSi sensors such as undesired reflections from imprecise positioning of the fiber optic cable and the PSi structure. Our design has three stages as hole milling for fiber socket, fabrication of filter structure, and integration of the fiber optic cable to the bulk Si. We have carried out reflectivity measurements of alcohols with close refractive index values by the proposed and conventional sensors. From the measurements, we note that both sensors have equal sensitivity in identifying alcohols, that repeatability of our proposed sensor is relatively higher, and that our sensor allows easy positioning and flexibility in sensing applications. Nonetheless, our proposed sensor necessitates a thorough fabrication process and a methodological preparation.