Sputter deposited p-NiO/n-SnO2 porous thin film heterojunction based NO2 sensor with high selectivity and fast response

Mangalam, S Kiruba; Jose, Anu; Prajwal, Kumar; Chowdhury, P.; Barshilia, Harish C.

doi:10.1016/j.snb.2020.127830

Cited by 33 publications

(15 citation statements)

References 45 publications

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“…In general, CO and NH 3 being a reducing gas should decrease the resistance of a sensing film depending on the operating conditions. 29 The obtained experimental results are consistent with the theory (Figure 7a−h). 13 Strong variation in the sensing behavior was observed in ATO films compared to TO films toward CO and NH 3 gas detection.…”

Section: Gas Sensor Device Performancesupporting

confidence: 89%

“…Surface resistance is more influenced by the charge state of the adsorbed oxygen. 29 The charge state of the adsorbed oxygen (O 2 − , O 2− , O − ) depends on the operating temperature of a sensor. 29,45 For example, sensors operating between 100 to 300 °C exhibit an O 2 − charge state.…”

Section: Gas Sensor Device Performancementioning

confidence: 99%

“…29 The charge state of the adsorbed oxygen (O 2 − , O 2− , O − ) depends on the operating temperature of a sensor. 29,45 For example, sensors operating between 100 to 300 °C exhibit an O 2 − charge state. During the exposure of the target gases on a film surface, oxygen ions are adsorbed by leaving electrons on the surface.…”

Section: Gas Sensor Device Performancementioning

confidence: 99%

“…Sensing behavior in the presence of reduced gas is effectively controlled by a total resistance of the shell and core properties of the films, which are schematically presented with the energy band diagram of SnO 2 and Sb-doped SnO 2 samples in Figure 8, parts b, d, f, and h. Cores usually contain strongly bound electrons, whereas shells usually contain loosely bound electrons and also the free electron provided by the doping process. 29 The surface charge carrier plays a major role in the charge transfer process of the gas sensor. 7 In addition, the surface exhibits free electrons, which promotes an effective charge transfer process.…”

Section: Gas Sensor Device Performancementioning

confidence: 99%

“…A variation in electron depletion layer width causes the Fermi level to shift when the film is exposed to a target gas. 29 The large variation in the EDL layer may cause the more Fermi level to shift toward the vacuum level, leading to significant variation in the potential difference. 29 Hence, surface resistance varies in response to this potential difference.…”

Section: Gas Sensor Device Performancementioning

confidence: 99%

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Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO₂ Films toward CO and NH₃ Gases

Ramanathan

Nagarajan

Bonu

et al. 2023

ACS Appl. Nano Mater.

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Thin film technology offered several possibilities and advancements in modern gas sensor devices. We have developed template-free, Sb-doped nanometer thin-SnO 2 films for CO/NH 3 gas detection using a facile spray technique on the glass substrates. Structural, surface, optical, and resistivity properties of as-deposited films were investigated as a function of film thickness for enhanced gas sensor performance. Structural analysis confirms tetragonal phase formation along with the texture behavior of the films. Increasing film thickness leads to an increase in the texture growth of the film, which can also impact gas sensing. As-deposited films display a polygon microstructure with dense film formation, leading to a large sensing surface. HR-TEM analysis confirms that Sb-doped nanometer-thin SnO 2 (ATO) films have a relatively low crystallite size than pristine TO films. Pristine SnO 2 (TO) film has better bandgap matching with bulk SnO 2 samples. ATO thin films have relatively lower band gap values and decrease as a function of film thickness due to enhanced free carrier density upon Sb doping. To determine the best optimum condition, gas sensing analysis was investigated at different operating temperatures (150, 200, and 250 °C) for different gas concentrations (5 to 25 ppm). Designed TO and ATO film base sensors exhibit rectifying gas-sensing behavior, indicating the formation of a potential barrier across the film surface and metal (Au) interface. ATO film-based gas sensor devices showed enhanced response toward CO/NH 3 gas detection compared to pristine TO thin film. Also, ATO thin films exhibited better stability and selectivity toward CO gas detection than NH 3 gas. However, the ATO film with very low resistance below 1 kΩ is not able to be used as a gas sensor. Hence, the results obtained indicate the optimum resistive behavior of nanometer ATO films' applicability toward enhanced CO/NH 3 gas detection.

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Section: Gas Sensor Device Performancesupporting

confidence: 89%

Section: Gas Sensor Device Performancementioning

confidence: 99%

Section: Gas Sensor Device Performancementioning

confidence: 99%

Section: Gas Sensor Device Performancementioning

confidence: 99%

Section: Gas Sensor Device Performancementioning

confidence: 99%

See 3 more Smart Citations

Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO₂ Films toward CO and NH₃ Gases

Ramanathan

Nagarajan

Bonu

et al. 2023

ACS Appl. Nano Mater.

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Interface Oxygen Vacancy‐Enhanced Co₃O₄/WO₃ Nanorod Heterojunction for Sub‐ppm Level Detection of NO_x

Manoharan,

Govindharaj,

Muthumalai

et al. 2023

Adv Eng Mater

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In this work, we developed and optimized a cobalt oxide/tungsten oxide (Co3O4/WO3) p‐n heterojunction for NOx detection. Field emission scanning electron microscopy showed that the WO3 nanorods were embellished with Co3O4 nanostructure. X‐ray photoelectron spectroscopy revealed the presence of oxygen vacancy on the Co3O4 coupled with WO3 heterojunction. Compared to bare WO3 and pure Co3O4, the Co3O4/WO3 heterojunction sensor showed significant sensitivity to NOx at 200oC. The sensor exhibited higher linearity from 0.4 to 10 ppm of NOx, with a sensing response of 4.4% to 93%. The NOx sensitivity of the Co3O4/WO3 heterojunction sensor was 9‐fold higher than that of the pure WO3 sensor. Even at a high humidity (84%) environment, the Co3O4/WO3 heterojunction sensor demonstrated high NOx sensitivity. The sensor maintained remarkable stability measured for up to 4 weeks. We additionally discussed the possible NOx sensing mechanism of the Co3O4/WO3 heterojunction.This article is protected by copyright. All rights reserved.

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Functionalization of Mesoporous Semiconductor Metal Oxides for Gas Sensing: Recent Advances and Emerging Challenges

et al. 2022

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With the emerging of the Internet of Things, chemiresistive gas sensors have been extensively applied in industrial production, food safety, medical diagnosis, and environment detection, etc. Considerable efforts have been devoted to improving the gas-sensing performance through tailoring the structure, functions, defects and electrical conductivity of sensitive materials. Among the numerous sensitive materials, mesoporous semiconductor metal oxides possess unparalleled properties, including tunable pore size, high specific surface area, abundant metal-oxygen bonds, and rapid mass transfer/diffusion behavior (Knudsen diffusion), which have been regarded as the most potential sensitive materials. Herein, the synthesis strategies for mesoporous metal oxides are overviewed, the classical functionalization techniques of sensitive materials are also systemically summarized as a highlight, including construction of mesoporous structure, regulation of micro-nano structure (i.e., heterojunctions), noble metal sensitization (e.g., Au, Pt, Ag, Pd) and heteroatomic doping (e.g., C, N, Si, S). In addition, the structure-function relationship of sensitive materials has been discussed at molecular-atomic level, especially for the chemical sensitization effect, elucidating the interface adsorption/catalytic mechanism. Moreover, the challenges and perspectives are proposed, which will open a new door for the development of intelligent gas sensor in various applications.

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Sputter deposited p-NiO/n-SnO2 porous thin film heterojunction based NO2 sensor with high selectivity and fast response

Cited by 33 publications

References 45 publications

Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO₂ Films toward CO and NH₃ Gases

Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO₂ Films toward CO and NH₃ Gases

Interface Oxygen Vacancy‐Enhanced Co₃O₄/WO₃ Nanorod Heterojunction for Sub‐ppm Level Detection of NO_x

Functionalization of Mesoporous Semiconductor Metal Oxides for Gas Sensing: Recent Advances and Emerging Challenges

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Sputter deposited p-NiO/n-SnO2 porous thin film heterojunction based NO2 sensor with high selectivity and fast response

Cited by 33 publications

References 45 publications

Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO2 Films toward CO and NH3 Gases

Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO2 Films toward CO and NH3 Gases

Interface Oxygen Vacancy‐Enhanced Co3O4/WO3 Nanorod Heterojunction for Sub‐ppm Level Detection of NOx

Functionalization of Mesoporous Semiconductor Metal Oxides for Gas Sensing: Recent Advances and Emerging Challenges

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Product

Resources

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Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO₂ Films toward CO and NH₃ Gases

Enhanced Sensing Performance of Sb-Doped Nanometer-Thin SnO₂ Films toward CO and NH₃ Gases

Interface Oxygen Vacancy‐Enhanced Co₃O₄/WO₃ Nanorod Heterojunction for Sub‐ppm Level Detection of NO_x