Highly sensitive gas sensors on low-cost nanostructured polymer substrates (original) (raw)
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An Efficient Nanoparticles-SnO2 Gas Sensor For Industrial Applications
The sensor presented in this article consists of a nanostructured tin oxide as high sensitive material and an efficient high temperature microhotplate. Tin oxide nanoparticles are in suspension in a solvent and then are deposited by contactless methods such as microinjections or inkjet printing. The microhotplate has been developed with high electrical and mechanical stabilities up to 650°C with a low power of consumption (<80 mW) and allows an efficient control of temperature, usefull for gases detection. In this work, the gas sensor developed is exposed to different polluting gases like CO, propane and NO2 at different operating temperatures. We determined the optimum working temperature to obtaine the highest sensitivity for each target gas. It is also demonstrated that these gas sensorspresent a best sensitivity compared to commercial Metal oxide gas sensors.
Novel fabrication of an SnO2 nanowire gas sensor with high sensitivity
2008
We fabricated a nanowire-based gas sensor using a simple method of growing SnO 2 nanowires bridging the gap between two pre-patterned Au catalysts, in which the electrical contacts to the nanowires are self-assembled during the synthesis of the nanowires. The gas sensing capability of this network-structured gas sensor was demonstrated using a diluted NO 2 . The sensitivity, as a function of temperature, was highest at 200 • C and was determined to be 18 and 180 when the NO 2 concentration was 0.5 and 5 ppm, respectively. Our sensor showed higher sensitivity compared to different types of sensors including SnO 2 powder-based thin films, SnO 2 coating on carbon nanotubes or single/multiple SnO 2 nanobelts. The enhanced sensitivity was attributed to the additional modulation of the sensor resistance due to the potential barrier at nanowire/nanowire junctions as well as the surface depletion region of each nanowire.
CMOS Integrated Nanocrystalline SnO 2 Gas Sensors for CO Detection
Procedia Engineering, 2016
In this work, we present gas sensors based on nanocrystalline SnO2 ultrathin films, which were integrated on microhotplate chips fabricated by CMOS technology. The gas sensitive films, with a thickness of 50 nm, were deposited on the microhotplate by a spray pyrolysis process. The CMOS integrated sensor resistance was significantly decreased in the presence of carbon monoxide. A sensor response of up to 50% is achieved at an operating temperature of 375 °C. The microhotplate chips presented here enable 3D integration of different gas sensing systems by through-silicon-via technology. Such 3D-integrated nanosensors are promising candidates for building smart gas sensor devices for daily life applications.
Synthesis and use of a novel SnO2 nanomaterial for gas sensing
Applied Surface Science, 2000
bstract w Ž . x Decomposition of the organometallic precursor Sn NMe in a controlled waterranisol mixture leads to the 2 2 2 formation of monodisperse nanocomposite particles of SnrSnO . Full oxidation of the particles into SnO occurs at 6008C x 2 without size or morphology change. These particles can be deposited onto silicon nitride covered microelectronic platforms and used as sensitive layers of gas sensors. Doping of the sensors with palladium can be achieved either by co-decomposi-Ž . tion of organometallic precursors doping in volume or by deposition of palladium on preformed SnO nanoparticles 2 Ž
Procedia Engineering, 2014
We present gas sensor devices based on nanocrystalline SnO2 films, which are integrated on CMOS fabricated micro-hotplate (μhp) chips. Bimetallic nanoparticles (NPs) such as PdAu, PtAu, and PdPt have been synthesized for optimizing the sensing performance of these sensors. We demonstrate that proper functionalization with PdAu-NPs leads to a strongly improved sensitivity to the toxic gas carbon monoxide while the cross sensitivity to humidity and carbon dioxide is almost completely suppressed, which is of high importance for real life environmental conditions. We also present μhp chips employing Through-Silicon-Via (TSV) technology, which are capable for flexible 3D-integration of different types of gas sensors to a multi-parameter nanosensor system. Such CMOS integrated systems are promising candidates for realizing smart sensor devices for consumer market applications.
Fabrication and H2-Sensing Properties of SnO2 Nanosheet Gas Sensors
ACS Omega, 2018
Vertically formed and well-defined SnO 2 nanosheets are easy to fabricate, involving only a single process that is performed under moderate conditions. In this study, two different sizes of a SnO 2 nanosheet were concurrently formed on a Pt interdigitated electrode chip, with interconnections between the two. As the SnO 2 nanosheets were grown over time, the interconnections became stronger. The ability of the fabricated SnO 2 nanosheets to sense H 2 gas was evaluated in terms of the variation in their resistance. The resistance of a SnO 2 nanosheet decreased with the introduction of H 2 gas and returned to its initial level after the H 2 gas was replaced with air. Also, the response−recovery behaviors were improved as a result of the growth of the SnO 2 nanosheets owing to the presence of many reaction sites and strong interconnections, which may provide multipassages for the electron transfer channel, leading to the acceleration of the reaction between the H 2 gas and SnO 2 nanosheets.
Applications of Nanostructured Materials as Gas Sensors
Gas detection instruments are increasingly needed for industrial health and safety, environmental monitoring, and process control. To meet this demand, considerable research into new sensors is underway, including efforts to enhance the performance of traditional devices, such as resistive metal oxide sensors, through nano-engineering. The resistance of semiconductors is affected by the gaseous ambient. The semiconducting metal oxides based gas sensors exploit this phenomenon. Physical chemistry of solid metal surfaces plays a dominant role in controlling the gas sensing characteristics. Metal oxide sensors have been utilized for several decades for low-cost detection of combustible and toxic gases. Recent advances in nanomaterials provide the opportunity to dramatically increase the response of these materials, as their performance is directly related to exposed surface volume. Proper control of grain size remains a key challenge for high sensor performance. Nanoparticles of SnO 2 have been synthesized through chemical route at 5, 25 and 50 o C. The synthesized particles were sintered at 400, 600 and 800 o C and their structural and morphological analysis was carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The reaction temperature is found to be playing a critical role in controlling nanostructure sizes as well as agglomeration. It has been observed that particle synthesized at 5 and 50 o C are smaller and less agglomerated as compared to the particles prepared at 25 o C. The studies revealed that particle size and agglomeration increases with increase in sintering temperature. Thick films gas sensors were fabricated using synthesized tin dioxide powder and sensing response of all the sensors to ethanol vapors was investigated at different temperatures and concentrations. The investigations revealed that sensing response of SnO 2 nanoparticles is size dependent and smaller particles display higher sensitivity.
On-chip fabrication of SnO 2nanowire gas sensor: The effect of growth time on sensor performance
Sensors and Actuators B-chemical, 2010
In this works, we report on the on-chip fabrication of SnO2-nanowire gas sensors by selective growth of the nanowires on Pt interdigitated at different grown time lengths. The gas-sensing properties of the on-chip fabricated sensors were characterized using liquefied petroleum gas (LPG) and NH3 gas at different operating temperatures. The effect of growth time on sensor performances was systematically investigated and reported. In addition, the influence of nanowire diameter and nanowire film thickness on gas sensor performance was also studied for thick film nanowire sensors fabricated by a screen-printing method to elucidate the sensing mechanisms of nanowire-based sensors. The results reveal that the diameter of SnO2 nanowires and their film thickness increased with increasing growth time. The response of the onchip fabricated SnO2-nanowire sensors varied from 1.4 to 21.8 with respect to the growth time, which was varied from 15 to 60 min. The increase of the sensor response with increasing growth time was attributed to the enhancement of wire-wire contact densities.
Micromachined nanocrystalline SnO 2 chemical gas sensors for electronic nose
Sensors and Actuators B-chemical, 2004
MEMS-based batch fabrication compatible sol-gel synthesized mesoporous nanocrystalline SnO 2 gas sensor has been developed. The SnO 2 nanofilm is fabricated with the combination of polymeric sol-gel chemistry and block copolymers used as structure directing agents. The novel hydrogen sensor has a fast response time (2 s) and quick recovery time (10 s), as well as good sensitivity (up to 90), in comparing to other hydrogen sensors developed. The working temperature of the sensor developed can be reduced as low as 100 • C. The low working temperature poses advantages such as lower power consumption; lower thermal induced signal shift as well as safe detection in certain environments where temperature is strictly limited. The nanocrystalline SnO 2 sensor has a broad sensitivity. The developed sensor cell will be used to develop a high sensitivity and high selectivity electronic nose for harmful chemical gas detection by combining different catalysts doped SnO 2 gas sensor array with fuzzy neural network.