Role of intragrain oxygen diffusion in polycrystalline tin oxide conductivity

Aldao, C. M.; Mirabella, D. A.; Ponce, Miguel Adolfo; Giberti, A; Malagù, C.

doi:10.1063/1.3561375

Cited by 26 publications

(25 citation statements)

References 25 publications

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“…2, the conductance changed its slope to the point that practically became temperature independent up to the highest temperature of our experiment, 358 • C (point E). We interpret this result as a consequence of oxygen diffusion into the grains, which is activated at temperatures above 200 • C. 13,14 As oxygen incorporates into the grains, the dopant concentration reduced and then the tunneling conduction was affected in such a way that compensates the temperature increasing effect (D-E).…”

confidence: 99%

“…c) No oxygen diffusion into or out of the grains occurs during the heating or cooling within the temperature range of the study. 13,14 In several articles, Eq. (1) is applied to estimate the φ value by plotting the conductance as a reverse function of temperature, without considering that the gas sensor is being cooled in vacuum, air, or CO, and that tunneling through the barriers can be significant.…”

confidence: 99%

“…Indeed, for temperatures above 220 • C, we have regularly detected that oxygen diffuses out the grains increasing considerably the density of vacancies that, in tin oxide, behave as donors. 13,14 Assuming that parabolic Schottky barriers form at the grain boundaries, the barrier height (φ), and singly ionized donor density (N d ) within a grain are directly related as follows 3…”

confidence: 99%

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Schottky barriers measurements through Arrhenius plots in gas sensors based on semiconductor films

2012

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The oxygen adsorption effects on the Schottky barriers height measurements for thick films gas sensors prepared with undoped nanometric SnO2 particles were studied. From electrical measurements, the characteristics of the intergranular potential barriers developed at intergrains were deduced. It is shown that the determination of effective activation energies from conduction vs. 1/temperature curves is not generally a correct manner to estimate barrier heights. This is due to gas adsorption/desorption during the heating and cooling processes, the assumption of emission over the barrier as the dominant conduction mechanism, and the possible oxygen diffusion into or out of the grains

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confidence: 99%

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Schottky barriers measurements through Arrhenius plots in gas sensors based on semiconductor films

2012

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“…A plausible explanation for this phenomenon has been given recently and it is out of the scope of the present work. 14 …”

Section: Calculation Of Schottky Barriers Heightsmentioning

confidence: 99%

“…However, the equilibrium oxygen vacancies density is far from constant implying a particular dependence on the amount of adsorbed oxygen and then on the ambient oxygen pressure. On the other hand, in previous works [10][11][12][13][14] we have demonstrated that not only thermionic emission is responsible for conductance but also tunneling has to be taken into account to explain observed changes in resistance. This is why we are very interested not only on the barriers height but also on the shape of the barriers, as tunneling depends on both.…”

Section: Introductionmentioning

confidence: 99%

Non-parabolic intergranular barriers in tin oxide and gas sensing

Aldao¹,

Malagù²

2012

Journal of Applied Physics

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Chemoresistive properties of crystalline solids strongly depend on the concentration of stoichiometric defects. In the case of tin oxide, oxygen vacancies are a case in point of such kind of defects. We address the problem of band bending and Schottky barrier formation in tin oxide. We approached the problem of charged native defects, oxygen vacancies, in a metal oxide in equilibrium with an oxygen containing ambient under three equivalent points of view. We focused on the non-parabolic barriers character that form at intergrains. Implications in electrical responses to oxygen concentration variations will be discussed

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Experiment and Theoretical Calculation of the Surface Space Charge Region Effect on Photocurrent Generation of SnO₂ Bilayer Photodiode Devices

Liao

Lee

Lin

et al. 2019

Adv Elect Materials

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to prolong the lifetime of the photocarriers of the photodetectors. [8][9][10][11] Das et al. reported the surface oxygen ion-adsorption on the oxygen-annealed SnO 2 surface would trap free electrons from the conduction band of SnO 2 , which results in an electrical potential built in the space charge region in the SnO 2 surface layer of SnO 2 -based UV-photodetectors. [3] As the photocarriers are generated by UV illumination on the SnO 2 surface layer of SnO 2 -based UV-photodetectors, the photocarriers would be separated by the electrical field built in the surface space charge region. As a result, the lifetime of the photocarriers can be enhanced. The abovementioned built-in electrical potential in the surface space charge region in the SnO 2 layer greatly depends on the oxygen vacancy concentration in the SnO 2 phase of the SnO 2 -based UV-photodetectors. Lee et al.'s study also stated that a critical oxygen vacancy concentration in the SnO 2 phase of the UV-photodetectors is required to create a sufficient built-in electrical potential in the surface space charge region to generate the detectable photocurrent. [12] So, they concluded that the critical electrical field required in the SnO 2 surface layer relies on the two criteria: 1) an adequate vacancy concentration in the SnO 2 layer, 2) oxygen ion-adsorption on the SnO 2 surface by annealing SnO 2 photodiode device in the O 2 ambient at elevated temperature. [12] However, for SnO 2 -based UV-photodiodes, the oxygen vacancies in the SnO 2 phase (causing low mobility) would trap the photocarriers and greatly reduce the lifetime of the generated photocarriers. Thus, the SnO 2 photocurrent generation layer with a high oxygen vacancy concentration would not be a good transportation path for the photocarriers.So, in this work, a SnO 2 bilayers photodiode device is studied, which consists of a thin SnO 2 photocurrent generation layer and a SnO 2 thick film on the glass substrate. The built-in electrical field in the thin SnO 2 photocurrent generation layer would drive the photocarrier down to and flow in the photocarrier transportation layer, i.e., the high-mobility SnO 2 thick film on the glass substrate. The designed SnO 2 bilayers photodiode device could enhance the photocurrent generation and the resolution for the SnO 2 -based UV-photodetectors.In this work, a SnO 2 bilayers photodiode device is designed, which consists of a thin SnO 2 photocurrent generation layer and a SnO 2 thick layer on the glass substrate. The SnO 2 photocurrent generation layer with high oxygen vacancy concentration is intentionally prepared. With annealing in oxygen ambient, an electrical potential would be built in the surface space charge region in the thin SnO 2 photocurrent generation layer, which would drive the photocarriers down to and flow in the photocarrier transportation layer, i.e., the high-mobility SnO 2 thick film on the glass substrate. The designed SnO 2 bilayers photodiode device could enhance photocurrent generation and resolution for the SnO 2 -based UV-photodete...

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Role of intragrain oxygen diffusion in polycrystalline tin oxide conductivity

Cited by 26 publications

References 25 publications

Schottky barriers measurements through Arrhenius plots in gas sensors based on semiconductor films

Schottky barriers measurements through Arrhenius plots in gas sensors based on semiconductor films

Non-parabolic intergranular barriers in tin oxide and gas sensing

Experiment and Theoretical Calculation of the Surface Space Charge Region Effect on Photocurrent Generation of SnO₂ Bilayer Photodiode Devices

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Role of intragrain oxygen diffusion in polycrystalline tin oxide conductivity

Cited by 26 publications

References 25 publications

Schottky barriers measurements through Arrhenius plots in gas sensors based on semiconductor films

Schottky barriers measurements through Arrhenius plots in gas sensors based on semiconductor films

Non-parabolic intergranular barriers in tin oxide and gas sensing

Experiment and Theoretical Calculation of the Surface Space Charge Region Effect on Photocurrent Generation of SnO2 Bilayer Photodiode Devices

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Product

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Experiment and Theoretical Calculation of the Surface Space Charge Region Effect on Photocurrent Generation of SnO₂ Bilayer Photodiode Devices