Micromachined gas sensors for environmental pollutants

Abstract

An Au doped tin oxide thin ®lm was deposited as base material for carbon monoxide detection over a micromachined substrate. The performances of a recent technique to heat the device, named fast pulsed temperature supply, are presented. This technique exploits the property that, due to the very low thermal mass of the membrane, the term required to reach steady state conditions is very short (about 40 ms). The sensor heater is periodically supplied for very short terms, hundred of milliseconds, and kept off for long ones, seconds or more. Besides a strong reduction of power consumption compared with isothermal characterization, an increase of sensitivity is observed. Different shapes of the heating wave were examined and results are summarized and compared.

A Generalized Analytical Model for Joule Heating of Segmented Wires

“…Briand et al [28] and Dumitrescu et al [29] described the thermal behavior of microheaters on square-shaped membranes using commercial tools such as COSMOS and MEMCAD. Similarly, Faglia et al proposed a numerical technique using SOLIDIS-finite element simulation (FEM) for detecting environmental pollutants using a platinum-based double-spiral-shaped heater [30]. Iwaki et al developed a twodimensional numerical model using FEMLAB to study the thermal characteristics of calorimetric gas flow sensors [31].…”

H2S Micro Gas Sensor Based on a SnO2-CuO Multi-layer Thin Film

“…Therefore, many researches are dedicated to detect the H 2 S gas and to develop various H 2 S sensing materials. Over the past decade, metal oxide thin films such as zinc oxide [1], tin oxide [2], and titanium oxide [3] have been widely investigated for their use in a H 2 S gas sensor application. Among the metal oxide thin films, tin oxide (SnO 2 ) is considered as the most promising candidate for a gas sensor application.…”

Conversion of ethanol to acetone & other produces using nano-sensor SnO<sub>2</sub>(110): Ab initio DFT

“…In fact, the results obtained using the nano-spheres clearly demonstrate only the products of mono atomically dispersed Cu (only acetaldehyde is observed) with an apparently improved efficiency [3]. For this reason, it has become popular to apply temperature modulation techniques to metal oxide gas sensors in which the surface temperature is rapidly scanned through a range of temperatures in which there is a strong variation of the gas sensitivity with surface temperature [4][5][6][7].…”