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CMOS integrable metal oxide gas sensors In recent years the demand for cheap, easy to manufacture and low power consuming gas sensors has grown. Gas sensors are employed in indoor and outdoor air quality monitoring [1], smoke gas detection (e.g. fire, heating) [2], automobile industry (e.g. cabin, exhaust) [3], and many other fields. The majority of these gas sensors do not fulfill the criteria for low power consumption as well as low manufacturing costs. Gas sensors based on metal oxides are a promising candidate to achieve the demanded criteria [4]. Metal oxides provide a simple process chain for cheap fabrication. At elevated temperatures metal oxides interact with ambient gases via a charge exchange between gas molecules and the oxide itself. Therefore, the evaluation of the gas sensors sensitivity towards any gas can be done by a simple resistance measurement. Another advantage of metal oxides is their integrability with CMOS technology. For the application as gas sensing devices metal oxides can either be used as thin films, single nanowires, nanowire networks or nanowire arrays. Although MOX gas sensors show promising results concerning their sensitivity towards numerous gases, their distinctions between these gases still poses a challenging issue. The approach to solving this issue is the application of nanoparticles on the surface of the gas sensing material (functionalization). The goal is to modify the sensitivity of the sensing material to reduce cross-sensitivities. For the purpose of sensitivity control certain nanoparticles can be used. The deposition of the nanoparticles onto the gas sensing material is done by drop-coating. |