Gas sensing mechanisms

Summarizing the basics of the gas-sensing mechanism, oxygen molecules from the surroundings become chemisorbed (that is chemically bonded) to the surface atoms, the process being described by the reaction ... 

K. Zakrzewska, Gas sensing mechanism of Ti02-based thin films . Vacuum, 74, 335-338, (2004). 

The commonly accepted physico-chemical gas sensing mechanisms of SWCNT-based gas sensors are discussed in detail by several authors (Bradley 2003 Pengetfli,2009 Battie eta/.,2012b).These mechanisms,which will be described in Section 10.3, are the charge transfer between adsorbed gas molecules and SWCNTs, and the modulation of the Schottky barrier established between semiconducting SWCNTs and metallic electrodes. 

Gas sensing mechanism must be highlighted to improve the sensor performances. Two sensing mechanisms are considered in this section the charge transfer between adsorbed molecules and SWCNTs, and the Schottky barrier modulation at the contacts. 

Fig. 12.1 (a) Sketch of pure SnO film, only top surface portion reacted, (b) Sketch of gas-sensing mechanism between pure SnOj film and SWCNT/SnO film (Reprinted with permission from Gong et al. 2008, Copyright 2008 Elsevier)... 

Ce02 can be utilized to manufacture highly sensitive gas sensors. Gas sensing mechanism is based on the reactions of gas molecules with particle surfaces that alter the electron... 

Nakamura Y, Yoshioka H, Miyayama M, Yanagida H (1990) Selective CO gas sensing mechanism with CuO/ZnO heterocontact. J Electrochem Soc 137 940-943... 

Fig. 11.3 (a) Gas sensing mechanisms of n-type emd p-type semiconductors and the different connecting configuration between long nanoflbers and nanopaiticles or short nanofibers, (b) Schematic model of the three steps for the sensitization mechanism of the as-prepared nanofiber sensor, (c) Response of Sn02 hollow nanofibers versus thin films serving as a reference (a Reprinted with permission from Yoon et al. [55]. 2012 Elsevier b Reprinted with permission from Zhang et al. [73]. 2010 Elsevier c Reprinted with permission from Cho et al. [74]. 2011 Elsevier)... 

Chen D, Lei S, Chen Y (2011) A single polyairiline nanofiber field effect transistor and its gas sensing mechanisms. Sensors 11(7) 6509-6516. doi 10.3390/s110706509... 

Based on these calculations, two gas-sensing mechanisms were proposed and revealed that both surface reconstruction and charge transfer result in a change of electronic conductance of ZnO. When the gas molecule is adsorbed upon the surface, the electronic conductance of the... 

Yuan QZ, Zhao YP, Li LM, Wang TH (2009) Ab initio study of ZnO based gas sensing mechanisms Surftice reconstruction and charge transfer. J Phys Chem C 113(15) 6107... 

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