The electrical conductance of a tungsten trioxide (WO3) thick-film gas sensors under UV illumination has been investigated. Measurements have been performed in two different environments: in pure nitrogen and in dry synthetic air. The effect of light on the electrical behavior has then been evaluated and interpreted. In particular, the observed increase in conductance after illumination of the surface is expected to be due to interband electronic transitions, since the bandgap of the material is smaller than the energy of the incident photons. An evidence for strong contribution of surface chemical processes to this variation,through surface barrier modulation, is given in this work.
Evidence of a surface effect of UV light on WO3 thick-film gas sensors
GIBERTI, Alessio;GUIDI, Vincenzo;MALAGU', Cesare
2012
Abstract
The electrical conductance of a tungsten trioxide (WO3) thick-film gas sensors under UV illumination has been investigated. Measurements have been performed in two different environments: in pure nitrogen and in dry synthetic air. The effect of light on the electrical behavior has then been evaluated and interpreted. In particular, the observed increase in conductance after illumination of the surface is expected to be due to interband electronic transitions, since the bandgap of the material is smaller than the energy of the incident photons. An evidence for strong contribution of surface chemical processes to this variation,through surface barrier modulation, is given in this work.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
