A rate equation approach to the gas sensitivity of thin film metal oxide materials

Ahlers, S.; Müller, Gerhard; Doll, Theodor

doi:10.1016/j.snb.2004.11.020

Cited by 172 publications

(93 citation statements)

References 48 publications

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“…These results are consistent with previously observed sensing behavior in porous films which exhibit an asymmetric bell-shaped variation of the gas sensitivity with the sensor operation temperature [15]. The temperature at which the maximum sensitivity occurs is also dependant on the concentration of the gas [15].…”

Section: B Gas Sensing Measurementssupporting

confidence: 92%

“…The temperature at which the maximum sensitivity occurs is also dependant on the concentration of the gas [15]. The resistance changes observed in the sensor are due to the temperature dependant chemisorption of at the surface of the .…”

Section: B Gas Sensing Measurementsmentioning

confidence: 99%

“…As a result, the proportional change in the thickness of the nondepleted region (within each cluster/neck) may be lower at higher temperatures, contributing to a smaller change in the normalized resistance. The response and recovery times decrease with increasing temperature because the thermally activated adsorption and desorption processes occur (and balance out to equilibrium) more rapidly [17] and because the penetration of the gas into the sensing layer decreases [15].…”

Section: B Gas Sensing Measurementsmentioning

confidence: 99%

See 2 more Smart Citations

Fabrication, Structural Characterization and Testing of a Nanostructured Tin Oxide Gas Sensor

Partridge¹,

Field²,

Sadek³

et al. 2009

IEEE Sensors J.

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Abstract-A nanostructured SnO 2 conductometric gas sensor was produced from thermally evaporated Sn clusters using a thermal oxidation process. SnO 2 clusters were simultaneously formed in an identical process on a Si 3 N 4 membrane featuring an aperture created by a Focused Ion Beam (FIB). Clusters attached to the vertical edges of the aperture were imaged using a transmission electron microscope. The original morphology of the Sn cluster film was largely preserved after the thermal oxidation process and the thermally oxidized clusters were found to be polycrystalline and rutile in structure. NO 2 gas sensing measurements were performed with the sensor operating at various temperatures between 25 C and 290 C. At an operating temperature of 210 C, the sensor demonstrated a normalized change in resistance of 3.1 upon exposure to 510 ppb of NO 2 gas.The minimum response and recovery times for this exposure were 45 s and 30 s at an operating temperature of 265 C. The performance of the SnO 2 sensor compared favorably with previously published results. Finally, secondary ion mass spectrometry and X-ray photoelectron spectroscopy were used to establish the levels of nitrogen present in the films following exposure to NO 2 gas.

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Section: B Gas Sensing Measurementssupporting

confidence: 92%

Section: B Gas Sensing Measurementsmentioning

confidence: 99%

Section: B Gas Sensing Measurementsmentioning

confidence: 99%

See 1 more Smart Citation

Fabrication, Structural Characterization and Testing of a Nanostructured Tin Oxide Gas Sensor

Partridge¹,

Field²,

Sadek³

et al. 2009

IEEE Sensors J.

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“…The difference observed in these two parameters (α, S) as well as the dissimilar behaviour of the sensitivity as function of the temperature (Fig.5b) are a direct proof that the surface chemistry is significantly different in the two metal oxides, since the response modulation as function of the diameter is considered a second order effect in this diameter range (d > 100 nm) [31]. Actually, the bell-shaped form of the response with increasing surface temperature in MOX was explained by Ahlers et al [32] in terms of two competing surface processes and as a consequence the experimental curve for SnO 2 and CuO nanowires can be parameterised by means of two energetic parameters: the strength of Langmuir adsorption E ads of the NH 3 molecule at the surface, and the activation energy for the combustion reaction E RES . These two factors are thus the decisive parameters to explain the high-temperature drop-off of S. Despite the complete description of the NH 3 -CuO interaction mechanism is beyond the scope of this preliminary work, it can be concluded from the dissimilar response-to-temperature profile and assuming that E ads is comparable in both metal oxides that the activation energy E RES is larger for SnO 2 .…”

Section: Resultsmentioning

confidence: 54%

Copper (II) oxide nanowires for p-type conductometric NH3 sensing

Shao

Hernández-Ramírez

Prades

et al. 2014

Applied Surface Science

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Copper (II) oxide (CuO) is a metal oxide suitable for developing solid state gas sensors.Nevertheless, a detailed insight into the chemical-to-electrical transduction mechanisms between gas molecules and this metal oxide is still limited. Here, individual CuO nanowires were evaluated as ammonia (NH 3 ) and hydrogen sulphide (H 2 S) sensors, validating the p-type character of this semiconductor. The working principle behind their performance was qualitatively modelled and it was concluded that adsorbed oxygen at the surface plays a key role necessary to explain the experimental data. Compared to their counterparts of SnO 2 nanowires, an appreciable sensitivity enhancement to NH 3 for concentrations below 100 ppm was demonstrated.

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“…Interestingly, when properly choosing the operating temperature, the sensor demonstrated the opposite response to CO and NO 2 , respectively. The ability to distinguish between NO 2 and CO when employing low and high operation temperatures is due to the well-known bell-shaped response curves of metal oxide gas sensors [21] and the commonly lower detection temperatures for the case of NO 2 . Therefore, we tested the sensor at two different temperatures, chosen for maximizing the sensitivity and selectivity toward CO and NO 2 .…”

Section: Sensing Testsmentioning

confidence: 99%

Comparison of the Sensing Properties of ZnO Nanowalls-Based Sensors toward Low Concentrations of CO and NO2

et al. 2017

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This work focuses on the synthesis and gas sensing properties of ZnO nanowalls (ZnO NWLs) grown by a simple cheap chemical bath deposition method on a thin layer of aluminum (about 20 nm thick) printed on the Pt interdigitated electrodes area of conductometric alumina platforms. Post-deposition annealing in nitrogen atmosphere at 300 • C enabled the formation of a ZnO intertwined 2D foils network. A wide characterization was carried out to investigate the composition, morphology and microstructure of the nanowalls layer formed. The gas sensing properties of the films were studied by measuring the changes of electrical resistance upon exposure to low concentrations of carbon monoxide (CO) and nitrogen dioxide (NO 2 ) in air. The sensor response to CO or NO 2 was found to be strongly dependent on the operating temperature, providing a means to tailor the sensitivity and selectivity toward these selected target gases.

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A rate equation approach to the gas sensitivity of thin film metal oxide materials

Cited by 172 publications

References 48 publications

Fabrication, Structural Characterization and Testing of a Nanostructured Tin Oxide Gas Sensor

Fabrication, Structural Characterization and Testing of a Nanostructured Tin Oxide Gas Sensor

Copper (II) oxide nanowires for p-type conductometric NH3 sensing

Comparison of the Sensing Properties of ZnO Nanowalls-Based Sensors toward Low Concentrations of CO and NO2

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