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Investigation of structural, electrical and optical properties of the hybrid structure PbxSn1-xO2/TiO2: interface analysis and influence of substrate temperature

Grant number: 18/25241-4
Support type:Scholarships in Brazil - Master
Effective date (Start): June 01, 2019
Effective date (End): February 28, 2021
Field of knowledge:Engineering - Materials and Metallurgical Engineering
Principal Investigator:Luis Vicente de Andrade Scalvi
Grantee:Stevan Brayan Oliveira dos Santos
Home Institution: Faculdade de Ciências (FC). Universidade Estadual Paulista (UNESP). Campus de Bauru. Bauru , SP, Brazil

Abstract

The work involves the production and the characterization electrical, optical and morphological of PbxSn1-xO2 and TiO2 in the form of thin films, and their combination in the form of heterostructure. Besides, the study of the influence of substrate temperature on the properties of these samples will also be approached. The steps of the work are: 1) Deposition of thin films of PbxSn1-xO2 (with x ranging from 0.001 to 0.15, so that Lead may enter the matrix as a dopant, or may form a compound) and TiO2. 2) Synthesis of the hybrid structure PbxSn1-xO2 / TiO2 and study of the interface between the films. In both steps the substrate temperature will be a parameter adjusted during the deposition, in order to optimize the samples properties. The interest in the heterostructure between SnO2 and TiO2 is mainly in the constitution of the interface between the thin films, which can lead to the appearance of ferroelectric effect, due to the dopant Pb. Thus, the properties of this interface will be investigated when the substrate temperature is varied (during dip-coating deposition) and how this may contribute to the optimization of the ferroelectric effect. In addition, due to the possibility of PbTiO3 formation, the insertion of the Pb dopant is aimed for decrease of SnO2 bandgap, improvements in the conductivity of the heterostructure and the photovoltaic behavior. All of these characteristics contribute to the potential applicability of this heterostructure in data storage devices and, in addition, when combined with the high transmittance of PbxSn1-xO2 and TiO2, may present applicability in solar cells. Samples will be built using the sol-gel-dip-coating technique (SGDC). Measurements to be performed include: optical absorption in UV-Vis and FTIR, X-ray diffraction, confocal microscopy analysis, scanning electron microscopy and atomic force microscopy. Regarding the electrical characterization, measurements of IxV at different temperatures and with different sources of excitation, as well as measurements of polarization through cyclic voltammetry (to evaluate the ferroelectric effect and application in data storage devices) will be carried out. Microscopy is mainly aimed for evaluating the PbxSn1-xO2 / TiO2 interfaces, in addition to the surfaces of these layers. The main objective is the development of scientific and technological knowledge, and the contribution to the making of photovoltaic devices that can be used in solar cells, as well as the manufacture of data storage devices based on ferroelectric effect.