Fabrication of WO3 nanodot-based microsensors highly sensitive to hydrogen

Calavia, R.; Mozalev, Alexander; Vázquez, R.M.; Gràcia, I.; Cané, C.; Ionescu, Radu; Llobet, Eduard

doi:10.1016/j.snb.2010.06.055

Cited by 72 publications

(49 citation statements)

References 42 publications

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“…16) In contrast, there is the report that the optical hydrogen gas sensing property of Pt/WO 3 declined with an increase of humidity. 17) Therefore, the unified theory concerned with influence of humidity was not established and the further research was required. Particularly, it is considered that humidity dependence was different from other films because the Pt/WO 3 thin films prepared by the solgel process in this study.…”

Section: )mentioning

confidence: 99%

Influence of temperature and humidity on the electrical sensing of Pt/WO<sub>3</sub> thin film hydrogen gas sensor

Yamaguchi

Imamura

Nishio

et al. 2016

J. Ceram. Soc. Japan

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Platinum catalyst loaded tungsten oxide (Pt/WO 3 ) is a promising candidate as a hydrogen gas sensor material, which can detect it through optical and electrical sensing. The sensor, which can detect the hydrogen gas stably in various environments, is strongly demanded. In this study, we prepared the Pt/WO 3 thin film by the solgel method and evaluate the dependence of the hydrogen gas sensing property on measuring temperature and humidity. Hydrogen gas sensing property of Pt/WO 3 thin film was evaluated by measuring the electrical conductivity with humid (0100% of relative humidity) hydrogen gas exposure at various temperatures. The sensing property was declined in humid atmospheres because the water molecule adsorbing on the film surface disturbed the catalytic reaction between hydrogen and Pt surface. In addition, the catalytic combustion of hydrogen molecule on Pt was also disturbed by the adsorbed water. However, the heating at 60°C can remove the effect of water molecule and the film can detect hydrogen gas stably. From these results, it was considered that the degradation of sensor response in humid atmosphere was mainly dominated by adsorbing water on Pt catalyst surface.

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Section: )mentioning

confidence: 99%

Influence of temperature and humidity on the electrical sensing of Pt/WO<sub>3</sub> thin film hydrogen gas sensor

Yamaguchi

Imamura

Nishio

et al. 2016

J. Ceram. Soc. Japan

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“…Considering the presence of stoichiometric crystalline Nb 2 O 5 in the composition of sensing layer and with reference to recently 40 reported H 2 -sensing mechanism for the WO 3 nanostructures, 43 we assume that, in a hydrogen atmosphere molecular hydrogen dissociates on the surface of the platinum electrodes, giving hydrogen ions and electrons: (7) takes place only if the gas is completely oxidized on the sensor surface. Partially oxidized gas may not change the sensor resistance drastically or the surface reactions may retard, which might be the case of our NO nanofilm.…”

Section: Gas Sensing Mechanismmentioning

confidence: 99%

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

et al. 2014

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Nanostructured niobium oxide (NO) semiconductor is gaining increasing attention as electronic, optical, and electro-optic material. However, the preparation of stable NO nanofilms with reproducible morphology and behavior remains a challenge. 10Here we show a rapid, well-controlled, and efficient way to synthesize NO films with the self-organized columnlike nanostructured morphologies and advanced functional properties. The films are developed via the growth of a nanoporous anodic alumina layer, followed by the pore-directed 15 anodizing of the Nb underlayer. The columns may grow 30-150 nm wide, up to 900 nm long, with the aspect ratio up to 20, being anchored to a thin continuous oxide layer that separates the columns from the substrate. The as anodized films have a graded chemical composition changing from amorphous Nb 2 O 5 mixed with Al 2 O 3 , Si-, and P-containing species in the surface region to NbO 2 in the lower film layer. The post-anodizing treatments result in the controlled 20 formation of Nb 2 O 5 , NbO 2 , and NbO crystal phases, accompanied by transformation from nearly perfect dielectric to n-type semiconductor behavior of the films. The approach allows for the smooth film growth without early dielectric breakdown, stress-generated defects, or destructive dissolution at the respective interfaces, which is a unique situation in the oxide films on niobium. The functional properties of the NO films, revealed to date, allow for potential applications as nanocomposite capacitor dielectrics and active 25 layers for semiconductor gas microsensors with the sensitivity to ethanol and the response to hydrogen being among best ever reported.

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“…The MEMS technique has been employed for the fabrication of thin films [13] and nanodots [14] to fabricate gas sensing materials. Moon et al reported on a low power consumption NO 2 micro gas sensor based on semiconducting SnO 2 nano-powders synthesized via a co-precipitation method.…”

Section: Introductionmentioning

confidence: 99%

Controllable growth of ZnO nanowires grown on discrete islands of Au catalyst for realization of planar-type micro gas sensors

Nguyen

Quy

Hòa

et al. 2014

Sensors and Actuators B: Chemical

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Controllable growth of ZnO nanowires grown on discrete islands of Au catalyst for realization of planar-type micro gas sensors. Chemical, http://dx.doi. org/10.1016/j.snb.2013.11.043 Access to the published version may require subscription. N.B. When citing this work, cite the original published paper. Sensors and actuators. B, Abstract:The proper engineering design of gas sensors and the controlled synthesis of sensing materials for the high-performance detection of toxic gas are very important in the fabrication of handheld devices. In this study, an effective design for gas sensor chips is developed to control the formation of grown ZnO nanowires (NWs). The design utilizes the dendrite islands of Au catalyst deposited on and between Pt electrodes of a planar-type micro gas sensor so that NWs can grow on instead of a continuous Au seed layer. This method results in an increase of NW-NW junctions on the device and also eliminates current leakage through the seed layer, which results in a higher sensitivity. The results show that the developed gas-sensing devices could be used to monitor NO 2 at moderate temperature (~250 °C) and/or ethanol at a high temperature (~400 °C).

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Fabrication of WO3 nanodot-based microsensors highly sensitive to hydrogen

Cited by 72 publications

References 42 publications

Influence of temperature and humidity on the electrical sensing of Pt/WO<sub>3</sub> thin film hydrogen gas sensor

Influence of temperature and humidity on the electrical sensing of Pt/WO<sub>3</sub> thin film hydrogen gas sensor

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

Controllable growth of ZnO nanowires grown on discrete islands of Au catalyst for realization of planar-type micro gas sensors

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