Decay of photo-excited conductivity of Er-doped SnO2 thin films

Morais, Evandro Augusto de; Scalvi, Luís Vicente de Andrade

doi:10.1007/s10853-006-1320-0

Cited by 20 publications

(22 citation statements)

References 16 publications

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“…From equation (1), and with the help of a straightforward derivation [9], it can be shown that the variation of sample resistivity with time and temperature can be used to obtain important parameters related to electronic mobility. It can be shown that [9]:…”

Section: Results -Discussionmentioning

confidence: 99%

“…K f is a constant [9]. A plot of ln(slope/T) as function of 1/T yields the quantity (E cap -φ) directly from the curve inclination.…”

Section: Results -Discussionmentioning

confidence: 99%

“…For the shown data of conductivity decay of Er 3+ doped SnO 2 thin film, samples were irradiated with the fourth harmonic (266nm) of an Nd:YAG pulsed laser, with 10 Hz of pulse frequency, by 10 min, keeping constant temperature. More details on Er-doped samples and conductivity decay measurements have been published elsewhere [9]. Data are shown here only for comparison.…”

Section: Methodsmentioning

confidence: 99%

“…Recombination of electron-hole pairs with desorbed oxygen species leads to persistent photoconductivity (PPC) effect [8] in undoped SnO 2 sol-gel thin films at low temperature [7], and to an exponentiallike decay for RE-doped SnO 2 . The decay of photo-excited conductivity can be applied in order to understand the electron trapping phenomena [9]. The experiment may be summarized as follows: a monochromatic excitation may ionize intra-bandgap defects and electron-hole pairs, depending on the energy of the excitation irradiation.…”

Section: Introductionmentioning

confidence: 99%

“…After removing the illumination, the time-temperature dependence of charge carrier trapping by defects is measured and the thermally activated capture cross section of the dominating level is evaluated. Recently, the decay of excited conductivity of Er-doped SnO 2 have been recorded and the carrier trapping by Er-related defects have been modeled [7,9], where the excitation is obtained with the fourth harmonic of a Nd:YAG laser (266nm), which leads to ionization of intra-bandgap defect centers along with electron-hole pairs.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Optical excitation of charge carriers from intra-bandgap states in Ce-doped SnO[sub 2] thin films

Silva¹,

Pineiz²,

Morais³

et al. 2008

AIP Conference Proceedings

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Abstract. Optical excitation of Ce 3+ -doped SnO 2 thin films, obtained by the sol-gel-dip-coating technique, is carried out and the effects on electrical transport are evaluated. Samples are doped with 0.1at% of Ce, just above the saturation limit. The excitation is done with an intensity-controlled halogen-tungsten lamp through an interference filter, yielding an excitation wavelength of 513nm, 9 nm wide (width at half intensity peak). Irradiation at low temperature (25K) yields a conductivity increase much lower than above bandgap light. Such a behavior assures the ionization of intra-bandgap defect levels, since the filter does not allow excitation of electron-hole pairs, what would happen only in the UV range (below about 350nm). The decay of intra-bandgap excited levels in the range 250-320 K is recorded, leading to a temperature dependent behavior related to a thermally excited capture cross section for the dominating defect level.

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Section: Results -Discussionmentioning

confidence: 99%

“…K f is a constant [9]. A plot of ln(slope/T) as function of 1/T yields the quantity (E cap -φ) directly from the curve inclination.…”

Section: Results -Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Optical excitation of charge carriers from intra-bandgap states in Ce-doped SnO[sub 2] thin films

Silva¹,

Pineiz²,

Morais³

et al. 2008

AIP Conference Proceedings

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Electron trapping in the photo-induced conductivity decay in GaAs/SnO2 heterostructure

Bueno

Scalvi

2018

Appl. Phys. A

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The decay of photo-induced conductivity is measured for GaAs/SnO 2 heterostructure, after illumination with appropriate wavelength. The top oxide layer is deposited by sol-gel-dip-coating and doped with Eu 3+ , and the GaAs bottom layer is deposited by resistive evaporation. It shows quite unusual behavior since the decay rate gets slower as the temperature is raised. The trapping by intrabandgap defects in the SnO 2 top layer is expected, but a GaAs/SnO 2 interface arrest becomes also evident, mainly for temperatures below 100 K. Concerning the SnO 2 layer, trapping by different defects is possible, due to the observed distinct capture time range. Besides Eu 3+ centers and oxygen vacancies, this sort of heterostructure also leads to Eu 3+ agglomerate areas in the SnO 2 top layer surface, which may contribute for electron scattering. The electrical behavior reported here aims to contribute for the understanding of the electrical transport mechanisms which, combined with emission from Eu 3+ ions from the top layer of the heterostructure, opens new possibilities for optoelectronic devices because samples in the form of films are desirable for circuit integration. The modeling of the photo-induced decay data yields the capture barrier in the range 620-660 meV, and contributes for the defect rules on the electrical properties of this heterostructure.

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Investigation of sensing properties of sol–gel processed 4 at%Sb:SnO2/TiO2 thin films

Boratto

Ramos

Scalvi

2017

J Mater Sci: Mater Electron

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In this work we investigate the gas and photo sensing properties of the antimony doped tin oxide and titanium oxide (4 at%Sb:SnO 2 /TiO 2 ) nanocrystalline thin films deposited by sol-gel dip-coating. Photoconductivity measurements are carried out under solar light spectra irradiation at different powers. These results show a photo sensitivity of the films in a lateral junction due to interfacial defects. Gas sensitivity was studied at different pressures, and higher conductivity is presented at lower pressure compared to oxygen-rich atmosphere. It occurs due to absence of oxygen adsorption on the semiconductors surface. TiO 2 films are also investigated concerning its properties to gas sensing under photo-excitation with InGaN LED light source with wavelength centered in 450 nm. The decay of photo-induced current evaluated under O 2 and vacuum atmospheres shows that the sample illumination may contribute to higher gassensitivity. This measurement allows determining the charge carrier capture energy, that is related to trapping dominated by distinct defects in each atmosphere.

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Decay of photo-excited conductivity of Er-doped SnO2 thin films

Cited by 20 publications

References 16 publications

Optical excitation of charge carriers from intra-bandgap states in Ce-doped SnO[sub 2] thin films

Optical excitation of charge carriers from intra-bandgap states in Ce-doped SnO[sub 2] thin films

Electron trapping in the photo-induced conductivity decay in GaAs/SnO2 heterostructure

Investigation of sensing properties of sol–gel processed 4 at%Sb:SnO2/TiO2 thin films

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