A Study on Er3+ Substitution in Sol-gel BaTiO3 Thin Films Using X-ray Line Profile Analysis

Abstract

Perovskite erbium doped barium titanate (Ba_1-xEr_xTiO₃) thin films, at different x values, have been fabricated on SiO₂/Si substrate and characterized using X-ray diffraction (XRD) in the range of 20° to 60° to study the phase structure and geometric parameters for the films. XRD patterns show a broadening and shifting for the perovksite peaks toward higher angle due to Er³⁺ doping. The effect of Er³⁺ substitution into BaTiO₃ lattice has been deeply investigated using X-ray line profine analysis through Scherrer equation, Williamson-Hall and size-strain plot (SSP) approaches. For all approaches used, it has been found that the crystallite size for the films decreases as the value of x increases, which is attributed to the relatively small Er³⁺ ionic size compared to Ba²⁺. In Williamson-Hall and SSP analysis, it is found that the microstrain created due to Er³⁺ doping causes distortion for the lattice and broadening for perovskite peaks as a result. Among all approaches used in this work, SSP shows to be the most suitable for this type of materials by giving the best fitted plots and goodness of fit R² close to 1.

DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16225