Rare earth centers properties and electron trapping in SnO2 thin films produced by sol–gel route

Morais, Evandro Augusto de; Scalvi, Luís Vicente de Andrade; Cavalheiro, Alberto Adriano; Tabata, A.; Oliveira, José Brás Barreto de

doi:10.1016/j.jnoncrysol.2008.04.029

Cited by 29 publications

(35 citation statements)

References 24 publications

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“…It has been carried out for SnO 2 thin films with several sort of doping such as Er-doped and Eu-doped 26,36 or Sb-doped SnO 2 37 . However the scope here is not to model it but only to report the effect of monochromatic light excitation and current decay, and besides, to show the much faster effect of carrier capture compared to SnO 2 .…”

Section: Resultsmentioning

confidence: 99%

“…The decay of photo-induced electrons (n) from the conduction band to the trapping defect is given by a simple differential equation 38 , whose solution was previously published 36,37 . Considering that in this sort of oxides, the mobility (µ) is dominated by the grain boundary scattering, we may neglect bulk scattering mechanisms (phonon and ionized impurity).…”

Section: Referencesmentioning

confidence: 99%

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Emission Properties Related to Distinct Phases of Sol-Gel Dip-Coating Titanium Dioxide, and Carrier Photo-Excitation in Different Energy Ranges

Ramos

Boratto

et al. 2017

Mat. Res.

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Titanium dioxide (TiO 2 ) in the form of pellets (pressed powder) and thin films are investigated, revealing the presence of distinct phases: mainly anatase and rutile. Characterization of optical, structural and electrical properties were carried out on samples submitted to different sort of thermal annealing (TA), at distinct temperatures, 500 and 1000 o C, due to their influence on the obtained phases. TA temperature along with pressure application for sample conformation, determine the bands present in the photoluminescence (PL) spectra, being about 550nm, characteristic of anatase phase and 800nm, related to the presence of rutile phase. The bandgap of thin films is determined from optical absorbance data, yielding 3.4eV for anatase phase (indirect transition), and 2.9eV for rutile phase (direct transition). Besides, irradiation with monochromatic light strongly affects the thin film conductivity, but the energy range (above or below the bandgap energy) does not seem to affect the behavior, which is associated with the excitation of intrabandgap states or crystallites belonging to phases with distinct bandgaps.

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Section: Resultsmentioning

confidence: 99%

Section: Referencesmentioning

confidence: 99%

Emission Properties Related to Distinct Phases of Sol-Gel Dip-Coating Titanium Dioxide, and Carrier Photo-Excitation in Different Energy Ranges

Ramos

Boratto

et al. 2017

Mat. Res.

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“…22,24 Then, based on Fig. 1, the pH 4 sample would have more imperfections and symmetry break as compared to pH 7 and pH 11 pellets, because vibrations S 2 and S 3 are more intense in the pH 4 sample.…”

Section: Resultsmentioning

confidence: 99%

Nanoparticle characterization of Er-doped SnO2 pellets obtained with different pH of colloidal suspension

Ravaro¹,

Scalvi

Tabata

et al. 2013

Journal of Applied Physics

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SnO 2 :2 at. %Er xerogel samples were obtained by sol-gel technique from colloidal suspensions with distinct pHs. The evaluation of critical regions inside the nanocrystallite is fundamental for the interpretation of the influence of pH on the emission data. In this way, the nanocrystal depletion layer thickness was obtained with the help of photoluminescence, Raman, X-ray diffraction, and field-emission gun scanning electron microscopy measurements. It was observed that acid suspensions (pH < 7) lead to high surface disorder in which a larger number of cross-linked bonds Sn-O-Sn among nanoparticles are present. For these samples, the nanoparticle depletion layer is larger as compared to samples obtained from other pH. Photoluminescence measurement in the near infrared region indicates that the emission intensity of the transition 4 I 13/2 ! 4 I 15/2 is also influenced by the pH of the starting colloidal suspension, generating peaks more or less broadened, depending on location of Er 3þ ions in the SnO 2 lattice (high or low symmetry sites). V C 2013 AIP Publishing LLC. [http://dx

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“…It is important to mention that 628 nm is a higher wavelength (lower energy) compared with the SnO 2 bandgap (about 350 nm), as is 450 nm, which is far below the GaAs bandgap (about 870 nm) but still above the SnO 2 bandgap. The wavelength of 266 nm is below the SnO 2 bandgap (higher energy) and then, the corresponding energy (4.65 eV) was previously efficiently used for SnO 2 matrix excitation, concerning electron-hole generation in the evaluation of photo-induced electrical properties 30 , as well as in the energy transfer process for Eu 3+ excitation, leading to a highly efficient luminescence, in the evaluation of Eu-doped SnO 2 emission properties 6 . The excitation processes can be outlined by considering that the GaAs film is grown on top of the SnO 2 film.…”

Section: Resultsmentioning

confidence: 99%

Photo-Induced conductivity of heterojunction GaAs/Rare-Earth doped SnO2

et al. 2013

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Rare earth centers properties and electron trapping in SnO2 thin films produced by sol–gel route

Cited by 29 publications

References 24 publications

Emission Properties Related to Distinct Phases of Sol-Gel Dip-Coating Titanium Dioxide, and Carrier Photo-Excitation in Different Energy Ranges

Emission Properties Related to Distinct Phases of Sol-Gel Dip-Coating Titanium Dioxide, and Carrier Photo-Excitation in Different Energy Ranges

Nanoparticle characterization of Er-doped SnO2 pellets obtained with different pH of colloidal suspension

Photo-Induced conductivity of heterojunction GaAs/Rare-Earth doped SnO2

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