Metal oxide sensors

Nyberg 1988 metal oxide sensor layer whose reflectivity reversibly changes with p02... 

EN 50291 also determines the limits of cross-sensitivities to H2, C02, NO, S02, ethanol and hexamethyldisiloxane. The latter is known to cause poisoning of pel-listors and metal oxide sensors. 

Suitable methods for CO indoor monitoring are based on using metal oxide sensors (chapter 5.3.2.1), electrochemical cells (chapters 5.3.2.3 and 5.3.2.4), pellis-tors (chapter 53.2.2) and optical methods (chapter 5.3.2.5). An overview of CO-sensors and systems is given in Tab. 5.9. 

CO Resistive sensors pellistors, metal-oxide sensors Optical sensors micro-spectrometer, IR-sources, IR-detectors, IR-filters Hybrid or integrated, surface micromachining Sn02 sintered thick film (Figaro, FIS,. ..), Sn02 thin and thick film on silicon (MiCS, Microsens) IR spectroscopy (Vaisala, Honeywell,. ..)... 

Exhaust gases Smoke Resistive sensors pellistors, oxygen-sensors, metal-oxide sensors Hybrid or integrated Hybrid or integrated... 

Tomchenko, A. A. Harmer, G. P. Marquis, B. T., Detection of chemical warfare agents using nanostructured metal oxide sensors, Sens. Actuators B. 2005, 108,41 55... 

Metal oxide sensors (MOS), smart, 22 717 Metal oxide supported catalysts, 5 336-337 coke formation on, 5 267—270 Metal passivation, in industrial water treatment, 26 137 Metal peroxides, 18 410 Metal phosphates, tertiary, 18 840 Metal-phosphorus alloys, 19 59 Metal phthalocyanines, electrochromic materials, 6 572t, 576-577 Metal prefinishing, detersive systems for, 8 413t... 

The third block in Fig. 2.1 shows the various possible sensing modes. The basic operation mode of a micromachined metal-oxide sensor is the measurement of the resistance or impedance [69] of the sensitive layer at constant temperature. A well-known problem of metal-oxide-based sensors is their lack of selectivity. Additional information on the interaction of analyte and sensitive layer may lead to better gas discrimination. Micromachined sensors exhibit a low thermal time constant, which can be used to advantage by applying temperature-modulation techniques. The gas/oxide interaction characteristics and dynamics are observable in the measured sensor resistance. Various temperature modulation methods have been explored. The first method relies on a train of rectangular temperature pulses at variable temperature step heights [70-72]. This method was further developed to find optimized modulation curves [73]. Sinusoidal temperature modulation also has been applied, and the data were evaluated by Fourier transformation [75]. Another idea included the simultaneous measurement of the resistive and calorimetric microhotplate response by additionally monitoring the change in the heater resistance upon gas exposure [74-76]. 

W. Gopel and G. Reinhardt. Metal Oxide Sensors New Devices Through Tailoring Interface on the Atomic Scale , Sensors Update, Vol. 1, H. Baltes, W. Gopel, J. Hesse, Eds., Verlagsgesellschaft mbH Weinheim, Germany (1991). 

M. Graf, D. Barrettino, M. Zimmermann, C. Hagleitner, A. Hierlemann, and H. Baltes, S. Hahn, N. Barsan, and U. Weimar. CMOS Monolithic Metal-Oxide Sensor System Comprising a Microhotplate and Associated Circuitry , IEEE Sensors Journal 4 (2004), 9-16. 

Fig. 15.11 Discrimination of six hop varieties (see Fig. 15.10) by means of metal oxide sensor (MOS) and QMB sensor arrays...

MOS metal oxide sensor, MOSFET metal oxide semiconductor field-effect transistor, IR infrared, CP conducting polymer, QMS quartz crystal microbalance, IMS ion mobility spectrometry, BAW bulk acoustic wave, MS mass spectrometry, SAW siuface acoustic wave, REMPI-TOFMS resonance-enhanced multiphoton ionisation time-of-flight mass spectrometry... 

Wijesundera, C., Walsh, T. (1998) Evaluation of an electronic nose equipped with metal oxide sensors for cheese grading. Aust. J. Dairy Technol 53 141. 

Garcia-Gonzalez, D.L, Aparicio, R. (2002) Detection of defective virgin olive oils by metal-oxide sensors. Eur. Food Res. Technol. 215 118-123. 

Gretsch, C., Toury, A., Estebaranz, R., Liardon, R. (1998) Sensitivity of metal oxide sensors towards coffee aroma. Semin. Food Anal. 3 37-42. 

Ceramic films -in metal oxide sensors [SENSORS] (Vol 21)... 

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