Interface formation of nanostructured heterojunction SnO 2:Eu/GaAs and electronic transport properties
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2013-02-15
Autores
Pineiz, Tatiane F. [UNESP]
De Morais, Evandro A.
Scalvi, Luis V.A. [UNESP]
Bueno, Cristina F. [UNESP]
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Resumo
Thin films of tin dioxide (SnO2) are deposited by the sol-gel-dip-coating technique, along with GaAs layers, deposited by the resistive evaporation technique. The as-built heterojunction has potential application in optoelectronic devices, combining the emission from the rare-earth doped transparent oxide (Eu3+-doped SnO2 presents very efficient red emission) with a high mobility semiconductor. The advantage of this structure is the possibility of separation of the rare-earth emission centers from the electron scattering, leading to a strongly indicated combination for electroluminescence. Electrical characterization of the heterojunction SnO2:Eu/GaAs shows a significant conductivity increase when compared to the conductivity of the individual films, and the monochromatic light irradiation (266 nm) at low temperature of the heterojunction GaAs/SnO2:Eu leads to intense conductivity increase. Scanning electron microscopy (SEM) of the heterojunction cross section shows high adherence and good morphological quality of the interfaces substrate/SnO2 and SnO2/GaAs, even though the atomic force microscopy (AFM) image of the GaAs surface shows disordered particles, which increases with sample thickness. On the other hand, the good morphology of the SnO2:Eu surface, shown by AFM, assures the good electrical performance of the heterojunction. The observed improvement on the electrical transport properties is probably related to the formation of short conduction channels at the semiconductors interface, which may exhibit two-dimensional electron gas (2DEG) behavior. © 2012 Elsevier B.V. All rights reserved.
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Palavras-chave
Electrical conductivity, Gallium arsenide, Heterojunction, Interface, Tin dioxide, AFM, Conduction channel, Electrical characterization, Electrical performance, Electrical transport properties, Electronic transport properties, GaAs, GaAs surfaces, High-mobility semiconductors, Interface formation, Low temperatures, Monochromatic light, Nano-structured, Potential applications, Rare earth doped, Rare-earth emission, Red emissions, Sample thickness, Transparent oxides, Two-dimensional electron gas (2DEG), Atomic force microscopy, Deposits, Electric conductivity, Electron gas, Europium, Interfaces (materials), Optoelectronic devices, Resistive evaporation, Scanning electron microscopy, Semiconducting gallium, Sol-gels, Tin, Transport properties, Heterojunctions
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Applied Surface Science, v. 267, p. 200-205.