Enhanced H2S sensing properties of Gallium doped ZnO nanocrystalline films as investigated by DC conductivity and impedance spectroscopy

Girija, K.G.; Somasundaram, K.; Debnath, A.K.; Topkar, A.; Vatsa, R.K.

doi:10.1016/j.matchemphys.2018.04.104

Cited by 29 publications

(9 citation statements)

References 41 publications

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“…As our EDX analyses revealed, the NC effect could also be assigned to the increase in oxygen content in the air annealed samples. It is believed that the accumulation of charges (or ions) at the metal/semiconductor interface facilitated by excess oxygen, vacancies, defects, and interface charge states in gallium doped zinc oxide films are a reason for the observed NC at low frequencies . Studies on the current conduction mechanism in CdS/Sb 2 Te 3 heterojunctions has shown that the resonance‐antiresonance switching happens at critical frequency values where the conduction converts from tunneling to correlated barrier hopping .…”

Section: Resultsmentioning

confidence: 99%

Structural and electrical characterizations of the as grown and annealed Au/MοO₃/In/MoO₃/C bandpass filters

Khanfar

Qasrawi

Daraghmeh

et al. 2019

Micro & Optical Tech Letters

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In this work, the structural, morphology, and electrical properties of two 500 nm thick molybdenum trioxide layers that are sandwiched with indium slab of thickness of 200 nm (MoO 3 /In/MoO 3 [MIM]) to form a bandpass filter are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and impedance spectroscopy techniques, respectively. The MIM films which coated onto Au thin film substrates by the thermal evaporation technique under vacuum pressure of 10 −5 mbar was post annealed at 250 C in air atmosphere. While the XRD analysis revealed polycrystalline hexagonal lattice structure of the Au/MLM samples, the SEM and EDS analysis displayed grains of sizes of 350 nm and stoichiometric structure of MoO 3 . Electrically, indium layer which caused n-type conduction with donor level of 299 meV, forced the material to exhibit negative capacitance (NC) effect at high frequencies (above 1.1 GHz). The impedance spectroscopy which was recorded in the frequency domain of 0.01 to 1.80 GHz, also revealed low pass and high pass filters characteristics in the low and high frequency domains, respectively. The annealing of the Au/MIM samples, decreased the crystallite and grain sizes and increased the microstrain, the defect density and the stacking faults. Small amount of excess oxygen and some indium deficiency are observed upon annealing. In addition, the annealing shifted the donor level closer to the bottom of the conduction band and inverted the NC effect from high to low frequency regions. The study indicates the applicability of the Au/MIM/C structures as microwave cavities and parasitic capacitance cancellers in electronic circuits. K E Y W O R D S band filters, coating, hexagonal, molybdenum trioxide, negative capacitance

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Section: Resultsmentioning

confidence: 99%

Structural and electrical characterizations of the as grown and annealed Au/MοO₃/In/MoO₃/C bandpass filters

Khanfar

Qasrawi

Daraghmeh

et al. 2019

Micro & Optical Tech Letters

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“…Hence, providing reliable H 2 S sensors sensitive to parts per million level concentrations has become mandatory wherever it may occur. 25,26 Toxicology and environmental hazards of H 2 S 27−29 fall outside the scope of this manuscript.…”

Section: Chemical Sensors (See Below)mentioning

confidence: 99%

“…The long-term (8 h) and short-term (10 min) exposure levels permitted are 20 and 50 ppm, respectively, and hence, a monitoring and alarming system has to detect parts per million level contaminations. ,,, Even at lower concentration levels, H 2 S is harmful to humans; absorbed by the lungs, H 2 S molecules rapidly erode the respiratory system causing unconsciousness and death in acute cases. Hence, providing reliable H 2 S sensors sensitive to parts per million level concentrations has become mandatory wherever it may occur. , Toxicology and environmental hazards of H 2 S − fall outside the scope of this manuscript.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric Dependence of Thermoelectric Generation in SnO₂ Thin Films with Different Intergranular Potential Barriers Utilized for Self-Powered H₂S Sensor Fabrication

Hossein‐Babaei

Masoumi

Aghili

et al. 2021

ACS Appl. Electron. Mater.

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The profound contribution of grain boundaries to the Seebeck voltage generation in the polycrystalline semiconductors has recently been stated. Considering the direct link between the chemiresistive sensitivity and intergranular energy barrier, the “chemithermoelectric” (CTE) effect follows as the interrelating effect. Here, we compare the magnitude of the CTE effects in SnO2 thin films with different intergranular potential barriers and show that the Seebeck coefficient and CTE magnitude are both linearly related to the experimentally determined charge conduction barrier height. It is shown that exposing the samples to the H2S-contaminated air at elevated temperatures reversibly modifies the barrier height and, hence, the Seebeck voltage generated along the sample at the presence of a constant temperature gradient. The demonstrated effect is utilized for the fabrication of the first CTE-based H2S sensor. Safety regulations regarding this highly hazardous gas are tight and the presented device provides safer monitoring of the surrounds than its chemiresistive counterpart; natural aging brings its output closer to the alarming level preventing silent failure. Powered by a temperature gradient, the device detects the presence of sub-parts per million H2S concentrations in air requiring no electrical power source for operation.

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“…Gallium doped ZnO (GZO) nanocrystalline films have been synthesized by radio frequency magnetron sputtering and their gas sensing properties with respect to H 2 S were investigated [16]. Doping lead to enhanced sensing characteristics of the fabricated gas sensors and increased stability with respect to oxidation.…”

Section: Gallium Nps Based Sensorsmentioning

confidence: 99%

Gallium and indium nanomaterials for environmental protection

2020

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Recent advances in preparation and use of gallium and indium nanoparticles and nanocomposites are briefly presented. The following applications of the obtained materials are outlined: (i) Preparation of sensors for measuring in air of gaseous pollutants (carbon monoxide, nitrogen dioxide, hydrogen sulfide, ammonia, ozone, hydrogen), vapours of volatile organic compounds (methanol, ethanol, butanol, acetone, liquefied petroleum gas), and humidity, including the basics of the sensing mechanism; (ii) removal of water pollutants by photocatalysis and/or adsorption. Finally, conclusions are drawn about the potential of gallium and indium nanoparticles and nanocomposites and the further studies needed to achieve the implementation of these materials in the real life.

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Enhanced H2S sensing properties of Gallium doped ZnO nanocrystalline films as investigated by DC conductivity and impedance spectroscopy

Cited by 29 publications

References 41 publications

Structural and electrical characterizations of the as grown and annealed Au/MοO₃/In/MoO₃/C bandpass filters

Structural and electrical characterizations of the as grown and annealed Au/MοO₃/In/MoO₃/C bandpass filters

Atmospheric Dependence of Thermoelectric Generation in SnO₂ Thin Films with Different Intergranular Potential Barriers Utilized for Self-Powered H₂S Sensor Fabrication

Gallium and indium nanomaterials for environmental protection

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Enhanced H2S sensing properties of Gallium doped ZnO nanocrystalline films as investigated by DC conductivity and impedance spectroscopy

Cited by 29 publications

References 41 publications

Structural and electrical characterizations of the as grown and annealed Au/MοO3/In/MoO3/C bandpass filters

Structural and electrical characterizations of the as grown and annealed Au/MοO3/In/MoO3/C bandpass filters

Atmospheric Dependence of Thermoelectric Generation in SnO2 Thin Films with Different Intergranular Potential Barriers Utilized for Self-Powered H2S Sensor Fabrication

Gallium and indium nanomaterials for environmental protection

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Product

Resources

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Structural and electrical characterizations of the as grown and annealed Au/MοO₃/In/MoO₃/C bandpass filters

Structural and electrical characterizations of the as grown and annealed Au/MοO₃/In/MoO₃/C bandpass filters

Atmospheric Dependence of Thermoelectric Generation in SnO₂ Thin Films with Different Intergranular Potential Barriers Utilized for Self-Powered H₂S Sensor Fabrication