Photo-EMF sensitivity of porous silicon thin layer-crystalline silicon heterojunction to ammonia adsorption

Sensors (Basel). 2011;11(2):1321-7. doi: 10.3390/s110201321. Epub 2011 Jan 25.

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.

Keywords: gas sensors; heterojunction; photo-EMF; porous silicon.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adsorption / radiation effects
  • Ammonia / analysis*
  • Crystallization
  • Electrochemical Techniques / instrumentation
  • Electrochemical Techniques / methods*
  • Light*
  • Nanowires / chemistry
  • Nitrogen / analysis
  • Porosity / radiation effects
  • Silicon / chemistry*
  • Thermodynamics

Substances

  • Ammonia
  • Nitrogen
  • Silicon