Sb doping effects and oxygen adsorption in SnO2 thin films deposited via sol-gel

Geraldo, Viviany; Scalvi, Luís Vicente de Andrade; Morais, Evandro Augusto de; Santilli, Celso Valentim; Pulcinelli, Sandra Helena

doi:10.1590/s1516-14392003000400004

Cited by 39 publications

(16 citation statements)

References 21 publications

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“…The remaining concentrated solution was then deposited on glass substrates of about 1.0 mm thickness. This sort of substrate leads to good adherence of the deposited material, as previously verified by scanning electron microscopy (SEM), 18 and as also shown in this work. Additionally, such substrates resist thermal annealing temperatures for films fairly well.…”

Section: Methodssupporting

confidence: 86%

Interface Formation and Electrical Transport in SnO2:Eu3+/GaAs Heterojunction Deposited by Sol–Gel Dip-Coating and Resistive Evaporation

Pineiz

Scalvi

Saeki

et al. 2010

Journal of Elec Materi

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The natural n-type conduction of tin dioxide (SnO 2 ) may be compensated by trivalent rare-earth doping. In this work, SnO 2 thin films doped with Eu 3+ have been deposited by the sol-gel dip-coating (SGDC) process, topped by a GaAs layer deposited by the resistive evaporation technique. The goal is the combination of a very efficient rare-earth emitting matrix with a high-mobility semiconductor. The x-ray diffraction pattern of SnO 2 :Eu/GaAs heterojunctions showed simultaneously the crystallographic plane characteristics of GaAs as well as cassiterite SnO 2 structure. The electric resistance of the heterojunction device is much lower than the resistance of the SnO 2 :2 at.%Eu and GaAs films considered separately. Micrographs obtained by scanning electron microscopy (SEM) of the cross-section showed that the interface is clearly identified, exhibiting good adherence and uniformity. A possible explanation for the low resistivity of the SnO 2 :2 at.%Eu/GaAs heterojunction is the formation of small channels with two-dimensional electron gas (2DEG) behavior.

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Section: Methodssupporting

confidence: 86%

Interface Formation and Electrical Transport in SnO2:Eu3+/GaAs Heterojunction Deposited by Sol–Gel Dip-Coating and Resistive Evaporation

Pineiz

Scalvi

Saeki

et al. 2010

Journal of Elec Materi

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“…If, instead, this level can be attributed to V O , which becomes more dominant once the hydrogen donors are removed, then our calculated value is also in good agreement with this result. We note that a level at 0.28-0.35 eV has been observed in many n-type samples [75,[164][165][166] (as has the ∼0.15 eV level) [73][74][75]167], and that, in a study on SnO 2 nanoparticles [168], a switching of activation energy from 0.11 to 0.35 eV was observed in the largest nanoparticle when changing from low to high temperature.…”

Section: Sn Omentioning

confidence: 52%

Deep vs shallow nature of oxygen vacancies and consequentn-type carrier concentrations in transparent conducting oxides

Buckeridge

Catlow

Farrow

et al. 2018

Phys. Rev. Materials

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The source of n-type conductivity in undoped transparent conducting oxides has been a topic of debate for several decades. The point defect of most interest in this respect is the oxygen vacancy, but there are many conflicting reports on the shallow versus deep nature of its related electronic states. Here, using a hybrid quantum mechanical/molecular mechanical embedded cluster approach, we have computed formation and ionization energies of oxygen vacancies in three representative transparent conducting oxides: In 2 O 3 , SnO 2 , and ZnO. We find that, in all three systems, oxygen vacancies form well-localized, compact donors. We demonstrate, however, that such compactness does not preclude the possibility of these states being shallow in nature, by considering the energetic balance between the vacancy binding electrons that are in localized orbitals or in effective-mass-like diffuse orbitals. Our results show that, thermodynamically, oxygen vacancies in bulk In 2 O 3 introduce states above the conduction band minimum that contribute significantly to the observed conductivity properties of undoped samples. For ZnO and SnO 2 , the states are deep, and our calculated ionization energies agree well with thermochemical and optical experiments. Our computed equilibrium defect and carrier concentrations, however, demonstrate that these deep states may nevertheless lead to significant intrinsic n-type conductivity under reducing conditions at elevated temperatures. Our study indicates the importance of oxygen vacancies in relation to intrinsic carrier concentrations not only in In 2 O 3 , but also in SnO 2 and ZnO.

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“…Convém ressaltar que esse comportamento relacionado a um comprimento de onda de plasma baixo significa alta concentração de elétrons livres, da ordem de 10 20 cm -3 [20]. Esse tipo de comportamento, ou seja, dependência das curvas de refletância e transmitância no infravermelho próximo, em função da concentração de íons dopantes, já foi observada anteriormente para amostras de SnO 2 dopadas com Sb 5+ [19][20][21]. Como naquele caso o íon dopante é um doador, o comportamento observado foi o inverso, ou seja, a maior concentração de Sb 5+ leva a maior quantidade de elétron livres e conseqüentemente menor transmitância e maior reflexão no infravermelho próximo.…”

Section: Resultsunclassified

Resistividade do filme depositado via sol-gel e estado de oxidação do dopante Ce na matriz SnO2

et al. 2011

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Incorporação de Ce3+ ou Ce4+ em filmes finos de SnO2 depositados via sol-gel-dip-coating aumenta drasticamente a resistividade elétrica. No primeiro caso, temos comportamento aceitador do dopante, levando a matriz à alta compensação de carga. Por outro lado, para Ce4+, verifica-se aumento na largura da região de depleção do contorno de grão, resultando em maior espalhamento de elétrons. Medidas de caracterização elétrica sob pressão ambiente levam à barreiras de potencial mais altas do que as medidas sob vácuo, devido a adsorção de oxigênio na superfície das partículas. A presença de Ce3+ aumenta a transmitância no infravermelho, o que significa menor quantidade de elétrons livres. Dados de XANES confirmam que o tratamento térmico a 550 ºC dos filmes, ainda que promova oxidação parcial para Ce4+, preserva uma quantidade significativa (em torno de 60%) no estado Ce3+. Espectroscopia Raman mostra a evolução dos modos de vibração intra-grãos de SnO2 com o aumento da temperatura de tratamento térmico.

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Sb doping effects and oxygen adsorption in SnO2 thin films deposited via sol-gel

Cited by 39 publications

References 21 publications

Interface Formation and Electrical Transport in SnO2:Eu3+/GaAs Heterojunction Deposited by Sol–Gel Dip-Coating and Resistive Evaporation

Interface Formation and Electrical Transport in SnO2:Eu3+/GaAs Heterojunction Deposited by Sol–Gel Dip-Coating and Resistive Evaporation

Deep vs shallow nature of oxygen vacancies and consequentn-type carrier concentrations in transparent conducting oxides

Resistividade do filme depositado via sol-gel e estado de oxidação do dopante Ce na matriz SnO2

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