Sensitive and selective ammonia sensor based on porous silicon
Porous silicon film was used as ammonia (NH3) gas sensor. Porous silicon layers were fabricated on arsenic doped crystalline silicon via electrochemical anodization. The sensor can be easily fabricated by using Indium (In) interdigitated electrodes. Gas sensing measurement indicated that the fabricated sensor shows excellent sensitivity, selectivity and high response to ammonia gas. The good selectivity of the sensor to ammonia may be attributed to the weak interaction between the ammonia molecules and the porous silicon film. The lowest detection limit of the fabricated sensor to ammonia gas is 5 ppm at room temperature, showing its potential use for detecting freshness of fish and seafood.