Semiconducting oxide gas sensors

Shaw, G, Parkin, I. P, Pratt, K. F. E. and Williams, D. E. (2005) Control of semiconducting oxide gas-sensor microstructure by apphcation of an electric field during aerosol-assisted chemical vapour deposition. Journal of Materials Chemistry 15, 149-54. 

Vlachos DS, Papadopoulos CA, Avaritsiotis IN (1996) On the electronic interaction between additives and semiconducting oxide gas sensors. Appl Phys Lett 69 650-652... 

Vinod CP, Kulkami GU, Rao CNR (2003) Nanoscale catalysis by gold. In Carley A, Davies P, Hutchings G, Spencer M (eds) Surface chemistry and catalysis. Kluwer Academic, New York, pp 191-206 Vlachos DS, Papadopoulos CA, Avaritsiotis IN (1996) On the electronic interaction between additives and semiconducting oxide gas sensors. Appl Phys Lett 69 650-652... 

In the next section, a variety of solid state environment gases sensors (NO,, CO2, CO, SO2, O2, etc.) are reviewed, and attention is also paid to semiconducting metal oxide type. Also discussed are the extension of the operating temperature to the near-human temperature regimes and better sensing properties derived from the nanostructured semiconducting metal oxide gas sensors. 

Various types of solid-state NO2 sensors have been proposed based on semiconducting metal oxides (including heterocontact materials) [42-50,58,59,234-238], solid electrolytes [1,239,240], metal phthalocyanine [241], and SAW devices [242]. Among these NO2 sensors, the semiconducting metal oxides and solid electrolytes appear to be the best. Specifically, semiconducting metal oxide gas sensors are most attractive because they are compact, sensitive, of low cost, and have low-power consumption. Their basic mechanism is that the NO2 gas is adsorbed on the surface of the material this decreases the free electron density into the space-charge layer and results in a resistance increase [243]. 

General discussion about sensing with semiconducting metal oxide gas sensors... 

The operation of a metal-oxide gas sensor relies on the change in resistance of an n- or p-type semiconducting layer - mainly Sn02 - when exposed to reducing or oxidizing gases. 

Titanium dioxide supported gold catalysts exhibit excellent activity for CO oxidation even at temperatures as low as 90 K [1]. The key is the high dispersion of the nanostructured gold particles over the semiconducting Ti02 support. The potential applications of ambient temperature CO oxidation catalysts include air purifier, gas sensor and fuel cell [2]. This work investigates the effects of ozone pretreatment on the performance of Au/Ti02 for CO oxidation. 

E. Comini, G. Faglia, G. Sberveglieri, Z.W. Pan, and Z.L. Wang. Stable and highly sensitive gas sensors based on semiconducting oxide nanobelts . Applied Physics Letters 81 (2002), 1869-1871. 

---