Review: Influences of Semiconductor Metal Oxide Properties on Gas Sensing Characteristics

Saruhan, Bilge; Fomekong, Roussin Lontio; Nahirniak, Svitlana

doi:10.3389/fsens.2021.657931

Cited by 175 publications

(98 citation statements)

References 210 publications

(261 reference statements)

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“…This change of baseline occurs due to additional water molecules interacting with the adsorbed oxygen ions on the active sites of the sensing surface, through hydrogen ions (H+) and hydroxyl ions (OH−) [30,31]. This is particularly critical when detecting VOCs (reducing gas), as the water molecules interact with the MOX material and release the captured electrons [32]. As a result, the baseline resistance decreases with increasing humidity; therefore, we see the baseline resistance of both sensors at 90% r.h. to be lower than that at 40% r.h.…”

Section: Resultsmentioning

confidence: 99%

Nickel-Oxide Based Thick-Film Gas Sensors for Volatile Organic Compound Detection

Ayyala¹,

Covington²

2021

Chemosensors

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In this paper, we report on the development of a highly sensitive and humidity-tolerant metal-oxide-based volatile organic compound (VOC) sensor, capable of rapidly detecting low concentrations of VOCs. For this, we successfully fabricated two different thicknesses of nickel oxide (NiO) sensors using a spin-coating technique and tested them with seven different common VOCs at 40% r.h. The measured film thickness of the spin-coated NiO was ~5 μm (S-5) and ~10 μm (S-10). The fastest response and recovery times for all VOCs were less than 80 s and 120 s, respectively. The highest response (Rg/Ra = 1.5 for 5 ppm ethanol) was observed at 350 °C for both sensors. Sensors were also tested in two different humidity conditions (40% and 90% r.h.). The humidity did not significantly influence the observed sensitivity of the films. Furthermore, S-10 NiO showed only a 3% drift in the baseline resistance between the two humidity conditions, making our sensor humidity-tolerant compared to traditional n-type sensors. Thus, we propose thick-film NiO (10 μm) sensing material as an interesting alternative VOC sensor that is fast and humidity-tolerant.

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Section: Resultsmentioning

confidence: 99%

Nickel-Oxide Based Thick-Film Gas Sensors for Volatile Organic Compound Detection

Ayyala¹,

Covington²

2021

Chemosensors

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“…ture [24]. Different literature reports have shown that the gas response at low temperatures starts to disappear at around 200 °C and is replaced by the typical sensitivity response at high temperatures [13,20]. The optimum temperature depends on the sensing material and the sensed gas.…”

Section: Co Analysismentioning

confidence: 99%

“…One of them is that the type of oxygen species adsorbed on the oxide depends on temperature [28]. As mentioned, atomic species, which are more reactive than molecular species, predominate at temperatures above 150 • C [13]. Another fact is that the oxidation reaction is an activated process, where its rate increases with temperature.…”

Section: Co Analysismentioning

confidence: 99%

“…As a result of these reactions, an electronic variation is produced on the surface that can be verified by the change in capacitance, electrical resistance, work function, or changes in its optical properties [9]. Among the wide variety of investigations on gas sensors, the binary compounds SnO 2 and ZnO [13] and the ternaries SmCoO 3 and ZnAl 2 O 4 have been the most studied [14]. In fact, several studies have indicated that the trirutile-type antimonates ZnSb 2 O 6 and CoSb 2 O 6 are good candidates for application as gas sensors due to their interesting detection properties [15].…”

Section: Introductionmentioning

confidence: 99%

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Preparation of Powders Containing Sb, Ni, and O for the Design of a Novel CO and C3H8 Sensor

et al. 2021

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In this work, powders of NiSb2O6 were synthesized using a simple and economical microwave-assisted wet chemistry method, and calcined at 700, 800, and 900 °C. It was identified through X-ray diffraction that the oxide is a nanomaterial with a trirutile-type structure and space group P42/mnm (136). UV–Vis spectroscopy measurements showed that the bandgap values were at ~3.10, ~3.14, and ~3.23 eV at 700, 800, and 900 °C, respectively. Using scanning electron microscopy (SEM), irregularly shaped polyhedral microstructures with a size of ~154.78 nm were observed on the entire material’s surface. The particle size was estimated to average ~92.30 nm at the calcination temperature of 900 °C. Sensing tests in static atmospheres containing 300 ppm of CO at 300 °C showed a maximum sensitivity of ~72.67. On the other hand, in dynamic atmospheres at different CO flows and at an operating temperature of 200 °C, changes with time in electrical resistance were recorded, showing a high response, stability, and repeatability, and good sensor efficiency during several operation cycles. The response times were ~2.77 and ~2.10 min to 150 and 200 cm3/min of CO, respectively. Dynamic tests in propane (C3H8) atmospheres revealed that the material improved its response in alternating current signals at two different frequencies (0.1 and 1 kHz). It was also observed that at 360 °C, the ability to detect propane flows increased considerably. As in the case of CO, NiSb2O6’s response in propane atmospheres showed very good thermal stability, efficiency, a high capacity to detect C3H8, and short response and recovery times at both frequencies. Considering the great performance in propane flows, a sensor prototype was developed that modulates the electrical signals at 360 °C, verifying the excellent functionality of NiSb2O6.

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“…Accordingly, this process ends up in electron trapping from the valence band, which successively increases the concentration of holes near the surface. This explains why, in general, p-type materials exhibit lower electrical resistance in air when compared to n-type ones [18]. In spite of the technological importance of NiO material, the understanding of the gas-sensing mechanism involved in the detection of different types of gases continues to be in progress.…”

Section: Introductionmentioning

confidence: 99%

Insights about CO Gas-Sensing Mechanism with NiO-Based Gas Sensors—The Influence of Humidity

et al. 2021

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Polycrystalline NiO thick film-based gas sensors have been exposed to different test gas atmospheres at 250 °C and measured via simultaneous electrical resistance and work function investigations. Accordingly, we decoupled different features manifested toward the potential changes, i.e., work function, band-bending, and electron affinity. The experimental results have shown that the presence of moisture induces an unusual behavior toward carbon monoxide (CO) detection by considering different surface adsorption sites. On this basis, we derived an appropriate detection mechanism capable of explaining the lack of moisture influence over the CO detection with NiO-sensitive materials. As such, CO might have both chemical and dipolar interactions with pre-adsorbed or lattice oxygen species, thus canceling out the effect of moisture. Additionally, morphology, structure, and surface chemistry were addressed, and the results have been linked to the sensing properties envisaging the role played by the porous quasispherical–hollow structures and surface hydration.

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Review: Influences of Semiconductor Metal Oxide Properties on Gas Sensing Characteristics

Cited by 175 publications

References 210 publications

Nickel-Oxide Based Thick-Film Gas Sensors for Volatile Organic Compound Detection

Nickel-Oxide Based Thick-Film Gas Sensors for Volatile Organic Compound Detection

Preparation of Powders Containing Sb, Ni, and O for the Design of a Novel CO and C3H8 Sensor

Insights about CO Gas-Sensing Mechanism with NiO-Based Gas Sensors—The Influence of Humidity

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