Electro-optical porous silicon gas sensor with enhanced selectivity

A new type of gas sensor that enables simultaneous monitoring of the electrical and optical properties of the sensor structure has been developed. The sensor is based on a porous silicon (PS) optical interference filter layer, which was produced with an electrochemical etching process. This sensor structure provides a rapid response when subjected to ambient adsorbates. In addition, it offers an increased level of selectivity between different gases, thus addressing the unresolved problems related to PS gas sensing. Sensors with differing hygroscopic properties were produced, and their response to changes in relative humidity were tested. The sensors were also subjected to ethanol and dimethylformamide vapours, and their ability to differentiate between the studied gases was demonstrated.