Anatase-Rutile Transition and Photo-Induced Conductivity of Highly Yb-Doped TiO(2)Films Deposited by Acid Sol-Gel Dip-Coating Method

Author(s)

Pedrini, Luiz F. Kaezmarek ; Santos, Stevan B. O. ; Trino, Luciana D. ; Scalvi, Luis V. A.

• Document type: Journal article
• Source: JOURNAL OF ELECTRONIC MATERIALS; v. 49, n. 11, p. 11-pg., 2020-08-25.

Abstract

A method to prepare Yb-doped TiO(2)is proposed, using titanium isopropoxide and ytterbium oxide. Thin films and powders are produced through the sol-gel technique where the Yb concentrations are 0.01 at.%, 0.02 at.%, 1 at.%, 2 at.% 4 at.% and 8 at.%. The increase in the doping concentration intensifies gradually the sample transparency for the whole observed spectrum and reaches the transparency degree of the undoped sample with the highest concentration of ytterbium. By means of x-ray diffraction (XRD) we find that the solution's pH leads to the formation of a rutile structure which is compensated for by lanthanide doping, inhibiting the anatase-rutile phase transformation. Then, the XRD profile depends on the Yb concentration, being mostly anatase for undoped and highly (8 at.%) doped samples, with mixed ratios of these two phases in other concentrations. Maintaining an acid solution leads to fewer intergrain defects in the rutile structure contributing to higher conductivity. Photo-induced investigation of 8 at.% Yb-doped thin film, using several light sources leads to distinct behavior concerning the excitation of intra-bandgap states and/or electron-hole pairs. This result helps to understand the electronic transport in Yb-doped TiO(2)and shows that devices based on its conductivity may have improved performance by irradiation with controlled light energy. (AU)

• FAPESP's process: 18/25241-4 - Investigation of structural, electrical and optical properties of the hybrid structure PbxSn1-xO2/TiO2: interface analysis and influence of substrate temperature
• Grantee: Stevan Brayan Oliveira dos Santos
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 19/00683-7 - Deposition of heterostrucures of SnO2 and TiO2 by dip-coating using a two phase technique
• Grantee: Luiz Felipe Kaezmarek Pedrini
• Support Opportunities: Scholarships in Brazil - Master