Interface formation of nanostructured heterojunction SnO2:Eu/GaAs and electronic transport properties

Pineiz, Tatiane F.; Morais, Evandro Augusto de; Scalvi, Luís Vicente de Andrade; Bueno, Cristina F.

doi:10.1016/j.apsusc.2012.10.097

Cited by 18 publications

(11 citation statements)

References 23 publications

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“…Thus, the GaAs layer acts as a shield, preventing the light from reaching the SnO 2 layer. This behavior is similar to what was recorded for SnO 2 :Eu/GaAs, when the exact same light source was used [13]. Figure 4 shows a proposed model for the results of conductance as a function of the temperature presented in Figure 3.…”

Section: Electrical Transport Propertiessupporting

confidence: 61%

“…When the total of the desired layers was reached, samples were submitted to thermal annealing, which generally is at 500 • C for 1 h in the same furnace. Resulting thickness of films obtained by this procedure is about 300 nm [13]. The intermediate thermal treatment between layers was absent in the case where the SnO 2 film was deposited on top of GaAs.…”

Section: Synthesis Of Heterostructurementioning

confidence: 84%

“…It is important to mention that indications of the effect of confinement in a 2DEG-like potential has been found before [13]. Although the deposition procedures of these layers do not suggest that a 2DEG formation is possible for the samples, the obtained effect on the conductance indicates that some sort of interfacial conduction improvement is being generated.…”

Section: Electrical Transport Propertiesmentioning

confidence: 97%

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Photoluminescence of Rare-Earth Ions in the Nanocrystalline GaAs/SnO2 Heterostructure and the Photoinduced Electrical Properties Related to the Interface

2017

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Deposition of an SnO 2 thin film was carried out by sol-gel-dip-coating and doped with Ce 3+ or Eu 3+ , and a GaAs layer was deposited by resistive evaporation or sputtering. This investigation combines the emission properties of these rare-earth ions with the unique transport properties generated by the heterostructure assembly. Illumination with light with energy above the GaAs bandgap and below the SnO 2 bandgap drastically increases the GaAs/SnO 2 heterostructure conductance, which becomes practically temperature-independent. This was associated with the presence of interface conduction, possibly a two-dimensional electron gas at the GaAs/SnO 2 interface. This feature takes place only for the sample where the GaAs bottom layer is deposited via sputtering. Irradiation with energies above the SnO 2 bandgap only excites the top oxide layer. The heterostructure assembly GaAs/SnO 2 :Eu leads to emission from Eu 3+ , unlike SnO 2 deposition directly on a glass substrate, where the Eu 3+ transitions are absent. Eu emission comes along a broad band, located at a higher energy compared to Eu 3+ transitions, which are blue-shifted as the thermal annealing temperature increases. Luminescence from Ce 3+ ions in the heterostructure can be detected, but the ions overlap with emission from the matrix, and a cleaning procedure helps to identify Ce 3+ transitions.

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Section: Electrical Transport Propertiessupporting

confidence: 61%

Section: Synthesis Of Heterostructurementioning

confidence: 84%

Section: Electrical Transport Propertiesmentioning

confidence: 97%

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Photoluminescence of Rare-Earth Ions in the Nanocrystalline GaAs/SnO2 Heterostructure and the Photoinduced Electrical Properties Related to the Interface

2017

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“…The SnO 2 and GaAs combination may improve the electrical properties, as have been reported previously [17,18]. The junction of these two materials leads to a discontinuity in the valence and conduction bands, due to the Fermi level equality condition.…”

Section: Accepted Manuscriptmentioning

confidence: 77%

On the electrical properties of distinct Eu3+ emission centers in the heterojunction GaAs/SnO2

Bueno

Scalvi

2016

Thin Solid Films

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GaAs/SnO 2 :2%Eu heterojunctions are deposited by resistive evaporation and sol-gel-dip-coating techniques respectively, with the top layer thermally annealed at different temperatures. The sample annealed at 200°C/1 h has a much higher conductivity and a lower deepest level (79 meV) than the sample annealed at 400 o C/20 min, for which the deepest level value is 98 meV. The decay of photo-induced current at room temperature for these heterojunctions shows a decay of 48.8% from the initial value for a sample annealed at 200°C/1 h, compared to a decay of 54.2% from the initial value for a sample treated at 400 o C/20 min. The excitation source has a broad band with energy lower than 1.65 eV, assuring that no electron-hole pair is generated in the SnO 2 (top) layer. The data fitting seems to indicate that, although the grain boundary scattering dominates the mobility, the inclusion of time dependent terms is needed, such as multi-center capture or ionized impurity scattering. Photoluminescence data shows that the main Eu 3+ transition changes from 5 D 0 → 7 F 2 (related to ions located at asymmetric sites such as boundary layer) to 5 D 0 → 7 F 1 (related to ions located at symmetric sites), as the annealing temperature is increased.

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“…Other investigations on the luminescence properties of lanthanide-based systems with NPs, nanorods or systems assembled using sol-gel techniques have been reported in the literature [17,22,27,33,34,38,40,43,45,49,50,60,61,67,73,78,82,88,93,107,[127][128][129]133,136,140,142,143,149,163,[169][170][171]176,178,201,211,212,214,[235][236][237][238][239][240][241][242][243][244][245]…”

Section: Nanoparticles Nanorods and Sol-gel Processmentioning

confidence: 99%

Recent advances in lanthanide spectroscopy in Brazil

Silva

Capelo

Albuquerque

2016

Journal of Luminescence

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a b s t r a c tThis rev Q2 iew discusses recent advances in lanthanide spectroscopy involving luminescence applications carried out in Brazil. The revised topics include glasses, sol-gel, light-emitting diodes, nanoparticles, metal-organic frameworks, coordination polymers, thin films, energy transfer processes, upconversion and development of new theoretical tools. The important role played by Prof. Oscar L. Malta on this subject is evidenced by his many contributions to the broad range of investigations reported here and this review is dedicated to him, on the occasion of his 60th birthday.& 2015 Published by Elsevier B.V.

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Interface formation of nanostructured heterojunction SnO2:Eu/GaAs and electronic transport properties

Cited by 18 publications

References 23 publications

Photoluminescence of Rare-Earth Ions in the Nanocrystalline GaAs/SnO2 Heterostructure and the Photoinduced Electrical Properties Related to the Interface

Photoluminescence of Rare-Earth Ions in the Nanocrystalline GaAs/SnO2 Heterostructure and the Photoinduced Electrical Properties Related to the Interface

On the electrical properties of distinct Eu3+ emission centers in the heterojunction GaAs/SnO2

Recent advances in lanthanide spectroscopy in Brazil

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