Metal oxides, semiconductor sensors

B. M. Cordero, and M. Forina, Electronic Nose Based on Metal Oxide Semiconductor Sensors as a Fast Alternative for the Detection of Adulteration of Virgin Olive Oils, Anal. Chim. Acta 2002,459, 219 C. L. Honeyboume, Organic Vapor Sensors for Food Quality Assessment, J. Chem. Ed. 2000, 77, 338 E. Zubritsky, E-Noses Keep an Eye on the Future. Anal. Chem. 2000, 72. 

Several commercial evidential breath alcohol measurement devices are available. The principle of measurement is either infrared absorption spectrometry (most common), dichromate-sulfuric acid oxidation-reduction (photometric), GC (flame ionization or thermal conductivity detection), electrochemical oxidation (fuel cell), or metal-oxide semiconductor sensors. A list has been published of DOT-approved breath alcohol devices.Some of these devices are approved for screening only. In this case, the second or confirmatory breath alcohol determination must be performed with an approved evidential breath alcohol analyzer. Breath alcohol devices may also be used for the medical evaluation of patients at the point of care (e.g., emergency department). A Fourier transform infrared point-of-care breath analyzer capable of measurement of... 

Noble metal additives such as Pt, Pd, or Ag, are often added to metal oxide semiconductor sensor materials to enhance sensor response to a particular gas or class of gases [35]. Other metals, namely Be, Mg, Ca, Sr, Ba, have been used with tin oxide to enhance performance of an alcohol selective sensor [36], for example. Commercially produced metal oxide sensors may customarily use one or more of the above catalysts. 

METAL OXIDE SEMICONDUCTOR SENSORS FOR DETECTION OF TOXIC AND EXPLOSIVE GASES... 

Metal oxide semiconductor sensors for detection of toxic and explosive... 

This approach has been developed using commercial resistive-type metal oxide semiconductor sensors - for example, for early fire detection in coal mines (Lee and Reedy, 1999 Reimann et al, 2009). This concept is now also under development for field effect sensor devices based on SiC for the detection and quantification of, for example, NO2. It has initially been demonstrated that discrimination between different gases (such as H2, NH3 and CO) and different concentrations seems possible for both Pt and Ir gate field effect sensors (Bur et al, 2010 Bur et a/., 2011a). 

M. Pardo, G. SbervegUeri, Electronic olfactory systems based on metal oxide semiconductor sensor arrays. Mrs BuU. 29(10), 703-708 (2004)... 

N. EIBarbri, E. Llobet, N. El Bari, X. Correig, B. Bouchikhi, Electronic nose based on metal oxide semiconductor sensors as an alternative technique for the spoilage classification of red meat. Sensors 8, 142—156 (2008)... 

M.C.C. Oliveros, J.L.P. Pavon, C.G. Pinto, M.E.E Laespada, B.M. Cordero, M. Forina, Electronic nose based on metal oxide semiconductor sensors as a fast alternative for the detection of adulteration of virgin olive oils. Anal. Chimica Acta 459,219-228 (2002)... 

A. Amari, N.E. Beri, B. Bouchikhi, Qutility control of goat milk by a portable electronic nose based on metal oxide semiconductor sensors. Instrum. Measuc Metrologie 11,31 9 (2011)... 

Metal oxide semiconductor sensors for gas measurements tracking changes of reversible redox processes at the sensor surface caused by the analyte... 

T. Yamazaki, T. Ikeda, Y. Kano, H. Takao, M. Ishida, K. Sawada, Design and fabrication of complementary metal-oxide-semiconductor sensor chip for electrochemical measurement, Japanese Journal of Applied Physics 49 (2010) 04DL11. 

Obvintseva LA. Metal oxide semiconductor sensors for determination of reactive gas impurities in air. Ross Khim Zh (Russ) 2008 52 113-21. 

Electrical devices based on measurements, where no electrochemical processes take place, but the signal arises from the change of electrical properties caused by the interaction with the anal3 te. This group can be subdivided into metal oxide semiconductor sensors, organic semiconductor sensors, electrolytic coti-ductivity sensors, and electric permittivity sensors. 

Metal oxide semiconductor sensors can be prepared in many different ways, in any case the general advice is to produce a nano crystalline material in such a way the modulation of the surface conductance band population becomes dominant in the whole sensor providing the maximum sensitivity. Recently metal oxides growth in regular shapes such as nanosized belts and rods has shown peculiar properties. The characteristics of these stmctures, although interesting, have not yet resulted in practical improvements of performances. 

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