Structure and physicochemical properties of nanostructured metal oxide films for use as the sensitive layer in gas sensors

Белышева, Т. В.; Гатин, А. К.; Grishin, M. V.; Иким, М. И.; Matyuk, V. M.; Sarvadii, S. Yu.; Трахтенберг, Л. И.; Шуб, Б. Р.

doi:10.1134/s1990793115050048

Cited by 18 publications

(4 citation statements)

References 17 publications

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“…At the same time, the significant change in conductivity values seems to be associated with a different concentration of states at these levels. A similar type of temperature dependence of conductivity with several activation energies is also found for other metal oxide semiconductors. , …”

Section: Resultssupporting

confidence: 74%

“…A similar type of temperature dependence of conductivity with several activation energies is also found for other metal oxide semiconductors. 30,31 For a better understanding of the structural changes that occur when zinc is introduced into cobalt oxide and, as shown above, has a strong effect on the conductivity of the material, the samples were studied by EPR spectroscopy (Figure 6). Figure 6a shows the EPR spectra of all samples in the magnetic field range of 1450−1700 G with g eff = 4.21, which can be associated with Co 2+ ions in the high-spin (S = 3/2) state in an octahedral environment.…”

Section: Preparationmentioning

confidence: 99%

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Nanocrystalline Complex Oxides Zn_xCo_3–xO₄: Cobalt and Zinc Ions Impact on Large Growth of Conductivity

et al. 2022

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Cobalt oxide based nanostructures are perspective materials for gas sensors, photocatalysts, and other devices for ecology applications due to the high concentration of chemisorbed oxygen and catalytic activity in oxidation reactions. Finely dispersed nanocrystalline oxides Zn x Co3–x O4 (0 ≤ x ≤ 1) with a high level of conductivity have been synthesized by the chemical precipitation of oxalates with subsequent thermal treatment. Comprehensive studies of the morphology, electrophysical properties, nature and concentration of defects in the obtained materials were carried out. It is shown that the introduction of zinc atoms to the Co3O4 structure leads to a sharp increase in conductivity by more than 5 orders of magnitude. In addition, the zinc-induced interplay of Co2+ spin centers between tetrahedral and octahedral sites was revealed using the EPR method. The correlation between the conductivity and the concentration of Co2+ ions in tetrahedral and octahedral environments was established for the first time. The obtained results open up the possibility of fine-tuning the electronic properties of nanostructured Zn x Co3–x O4 by variation of zinc concentration in the samples.

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Section: Resultssupporting

confidence: 74%

Section: Preparationmentioning

confidence: 99%

Nanocrystalline Complex Oxides Zn_xCo_3–xO₄: Cobalt and Zinc Ions Impact on Large Growth of Conductivity

et al. 2022

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“…The shallow traps operate mostly at low temperatures, and the deeper traps are added at increasing temperature. These results are largely similar to those obtained in other studies. − …”

Section: Nanoparticle Parameterssupporting

confidence: 92%

Absorption of Infrared Radiation by an Electronic Subsystem of Semiconductor Nanoparticles

et al. 2016

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The frequency dependence of the cross section of photon absorption by semiconductor nanoparticles in the infrared range is considered. Light is absorbed by conduction electrons with plasmon formation and electrons in the traps both within the bulk and on the nanoparticle surface. The regularities of the photoabsorption cross section largely depend on the size of the nanoparticles. For sufficiently large nanoparticles, there appear only two characteristic peaks in the cross section distribution corresponding to light absorption by two types of electronsconduction electrons and electrons in the volume traps of nanoparticles. The number of electrons trapped on the surface is relatively small, and the electrons do not contribute to the total cross section of photoabsorption. In the case of photon absorption by quantum dots, the contribution of these surface electrons as well as a third peak is evident. This result occurs due to a complex dependence of the number of electrons in the traps on their depth and size of nanoparticles.

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“…To uniquely determine the distribution of conduction electrons inside In 2 O 3 , several parameters were obtained from experiment. In particular, the activation energies ε d = 7.4 × 10 –3 and ε O = 2 × 10 –2 (here and further we use the atomic units) were determined by measuring the sensor conductivity in vacuum and in air. , However, several important parameters, controlling absorption and desorption of oxygen and hydrogen, are unknown. They are obtained by comparing experimental and theoretical temperature dependencies of sensitivity Θ( P H 2 ; T ) and choosing the values that give the best agreement between experimental and theoretical sensitivities at corresponding temperatures at maxima of Θ( T ) curves for the case of concentration of hydrogen at 1100 ppm.…”

Section: Sensor Effectmentioning

confidence: 99%

Sensor Effect in Oxide Films with a Large Concentration of Conduction Electrons

et al. 2017

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This paper presents a joint experimental and theoretical investigation of sensor response of nanostructured In2O3 semiconductor thin films containing a large concentration of conduction electrons. The capture of the conduction electrons by oxygen adsorbates from air causes redistribution of the electrons inside the nanoparticles, resulting in reduction of the subsurface electron density, and the drop of the conductivity of nanoparticle thin films. When CO and H2 reduced gas analytes are introduced to the system, their reaction with previously adsorbed negative atomic oxygen ions O– releases electrons back to the nanoparticles, producing a noticeable increase of thin-film conductivity, which constitutes the sensor effect. This work presents a kinetic model of such processes, which allows us to a quantitative description of the sensor effect including dependence of sensor sensitivity on temperature. Concurrently, experiments are performed to quantify the sensor response by nanostructured In2O3 thin film as a function of temperature and hydrogen concentration upon addition of hydrogen gas to the gas medium. The measured response is described well by the theoretical model developed in this work.

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Structure and physicochemical properties of nanostructured metal oxide films for use as the sensitive layer in gas sensors

Cited by 18 publications

References 17 publications

Nanocrystalline Complex Oxides Zn_xCo_3–xO₄: Cobalt and Zinc Ions Impact on Large Growth of Conductivity

Nanocrystalline Complex Oxides Zn_xCo_3–xO₄: Cobalt and Zinc Ions Impact on Large Growth of Conductivity

Absorption of Infrared Radiation by an Electronic Subsystem of Semiconductor Nanoparticles

Sensor Effect in Oxide Films with a Large Concentration of Conduction Electrons

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Structure and physicochemical properties of nanostructured metal oxide films for use as the sensitive layer in gas sensors

Cited by 18 publications

References 17 publications

Nanocrystalline Complex Oxides ZnxCo3–xO4: Cobalt and Zinc Ions Impact on Large Growth of Conductivity

Nanocrystalline Complex Oxides ZnxCo3–xO4: Cobalt and Zinc Ions Impact on Large Growth of Conductivity

Absorption of Infrared Radiation by an Electronic Subsystem of Semiconductor Nanoparticles

Sensor Effect in Oxide Films with a Large Concentration of Conduction Electrons

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Product

Resources

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Nanocrystalline Complex Oxides Zn_xCo_3–xO₄: Cobalt and Zinc Ions Impact on Large Growth of Conductivity

Nanocrystalline Complex Oxides Zn_xCo_3–xO₄: Cobalt and Zinc Ions Impact on Large Growth of Conductivity