Bias dependent sensitivity in metal-oxide gas sensors

A. Varpula, S. Novikov, J. Sinkkonen, M. Utriainen

Research output: Contribution to journalArticleScientificpeer-review

27 Citations (Scopus)

Abstract

Bias voltage induced degradation of sensitivity is reported in tungsten trioxide gas sensors. Barrier limited conduction model is extended to cover the effect of the bias voltage. The bias voltage controls the electron density at the grain boundaries which in turn controls the oxygen ionization or chemically assisted electron trapping process. Combination of the conduction and the trapping model results in nonlinear I-V characteristics. Sensitivity is derived from I-V curves, which are largely influenced by trapping. A good fit with experimental results is achieved. According to the proposed model sensitivity degradation only occurs in regime, where traps are almost filled already in the thermodynamical equilibrium.

Original languageEnglish
Pages (from-to)134-142
Number of pages9
JournalSensors and Actuators, B: Chemical
Volume131
Issue number1
DOIs
Publication statusPublished - 14 Apr 2008
MoE publication typeNot Eligible

Fingerprint

Bias voltage
Chemical sensors
Oxides
metal oxides
Metals
trapping
sensitivity
sensors
electric potential
gases
degradation
conduction
Degradation
Voltage control
Ionization
Carrier concentration
Tungsten
tungsten
Grain boundaries
grain boundaries

Keywords

  • Bias voltage
  • Conduction model
  • Metal-oxide gas sensor
  • Sensitivity
  • Surface state model
  • Tungsten trioxide

Cite this

Varpula, A. ; Novikov, S. ; Sinkkonen, J. ; Utriainen, M. / Bias dependent sensitivity in metal-oxide gas sensors. In: Sensors and Actuators, B: Chemical. 2008 ; Vol. 131, No. 1. pp. 134-142.
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Bias dependent sensitivity in metal-oxide gas sensors. / Varpula, A.; Novikov, S.; Sinkkonen, J.; Utriainen, M.

In: Sensors and Actuators, B: Chemical, Vol. 131, No. 1, 14.04.2008, p. 134-142.

Research output: Contribution to journalArticleScientificpeer-review

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