gas sensors; porous silicon; heterojunction; photo-EMF
Issue Date
2011-01
Publisher
MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL
Citation
SENSORS, v. 11, NO 2, Page. 1321-1327
Abstract
A new method of using photo-electromotive force in detecting gas and controlling sensitivity is proposed. Photo-electromotive force on the heterojunction between porous silicon thin layer and crystalline silicon wafer depends on the concentration of ammonia in the measurement chamber. A porous silicon thin layer was formed by electrochemical etching on p-type silicon wafer. A gas and light transparent electrical contact was manufactured to this porous layer. Photo-EMF sensitivity corresponding to ammonia concentration in the range from 10 ppm to 1,000 ppm can be maximized by controlling the intensity of illumination light.