Abstract
We report the growth of micrometer-sized In2O3 octahedral structures, which are next aligned in chains using dielectrophoresis on top of microhotplates with prepatterned electrodes and integrated heater to work as chemoresistive gas sensors. The devices are relatively fast (180 s), highly sensitive (response up to ~256%), and selective toward NO2 in humid environments, showing little response to O2 and ethanol, and being completely insensitive to CO and CH4. The here-presented fabrication method can be easily extended as a cost-effective post-process in CMOS-compatible microhotplate fabrication and, thus, represents a promising candidate for indoor and outdoor air quality monitoring devices.
Highlights
The use of metal oxide (MOx) semiconductor micro and nanostructured materials in the field of chemoresistive gas sensors has gained importance over the last decades due to their stability, large-scale production potential, cost effectiveness, and high surface-to-volume ratio that attributes them higher sensitivity and faster response and recovery times when compared to thin films (Brunet et al, 2012; Xu et al, 2015; Chowdhury and Bhowmik, 2021), i.e., high performance
In this work we propose the use of individual chains of few indium oxide (In2O3) octahedral structures as main sensing element of gas sensors
To fabricate the sensing material, monocrystalline In2O3 octahedral structures were synthetized by means of a vapor-solid deposition mechanism, utilizing a chemical vapor deposition (CVD) furnace connected to a gas injection system
Summary
The use of metal oxide (MOx) semiconductor micro and nanostructured materials in the field of chemoresistive gas sensors has gained importance over the last decades due to their stability, large-scale production potential, cost effectiveness, and high surface-to-volume ratio that attributes them higher sensitivity and faster response and recovery times when compared to thin films (Brunet et al, 2012; Xu et al, 2015; Chowdhury and Bhowmik, 2021), i.e., high performance. The major drawback of these gas sensing materials is their lack of selectivity. Individual structure-based gas sensors show fast response due to lack of electrical potential barriers between the structures (Lupan et al, 2010; Samà et al, 2019; Chowdhury and Bhowmik, 2021). A compromise between both solutions is a smart approach to obtain fast and, simultaneously, effective responses
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