Heterojunctions of SnO2 for applications in optoelectronic devices:1) GaAs/SnO2, 2) grafeno/SnO2

Abstract

In recent years we have dedicated to the investigation of transport properties of the heterojunction SnO2 / GaAs, which has opened possibilities to several specific projects. In this context this PhD project can be suited, being divided into two lines of research: 1) Deposition of heterojunction of SnO2 with GaAs, where the SnO2 can be pure or doped with rare-earth ions, such as Er3 + or Eu3 +, because they present high efficiency of optical emission in this matrix. 2) synthesis of hybrid structure composed of SnO2 / graphene. In these lines, the investigation of thermally and photo-excited electrical transport as well as optical properties of these structures will be critical. The main objective is the development of scientific and technological knowledge, and contribution to the making of electroluminescent devices, transparent high mobility transistors and / or gas sensors combining transport both GaAs layer or graphene with the efficiency of emission of rare-earth in the SnO2 matrix. The electrical and optical characteristics of the films, when coupled in the form of heterojunction, can show improvement related to electric transport. Measurements to be taken include: resistivity and current-voltage depending on the temperature, optical absorption from UV to infrared, X-ray diffraction, photoluminescence, atomic force microscopy and scanning electron microscopy, to evaluate the interfaces substrate/SnO2 and SnO2/GaAs, since the interfacial conducting channel is an essential parameter for transport properties. Aiming to further explore the properties of these heterojunction interfaces, will be held optical excitation experiments of films, obtaining electrical signal and also optical emission. Production, characterization and application of the hybrid graphene and semiconductor oxide SnO2 will also be performed, where the properties of the hybrid structure will be investigated. The technique for the deposition of graphene is the mechanical exfoliation. The combination of metal oxides with graphene in a hybrid structure may be listed as an alternative to combine the properties of both materials.