The impact of 3D Raman imaging and HR-TEM analysis on the observed changes in the orientation of the crystallites in 3D flower-like nanostructured layers

Abstract

The presented study aims to explain the formation phenomena of titanium dioxide flower_like forms on Ti foil. TiO2 nanoforms were obtained by chemical oxidation using H2O2 and further crystallization at 600 °C under an argon atmosphere. The morphology of layers is determined by reaction time. Understanding the factors that indicate the transition sequence and control the phase stability may provide insight into how the properties of titanium dioxide nanomaterials can be manipulated. A cross-sectional view of the samples reveals the complex arrangement of grains and their different shapes. HR-TEM and 3D Raman spectroscopy allowed to gain new insights into the structure formation. Observations of vibrational modes of anatase (101) and (001) surfaces allow quantitatively defining the percentage of facets exposition. Moreover, the spectra collected from different z-heights for the sample and the analysis of the integrated intensity ratio of Eg (144 cm−1) and A1g (514 cm−1) anatase bands show the grains' variable nature. The results present that the inner layer of the nanostructure is composed of more oriented crystallites, in contrast to the oxide/substrate interface and the sample surface. The model of the growth mechanism of a multilayered TiO2 scale formed on Ti has been proposed. Data availability statementThe raw/processed data required to reproduce these findings cannot be shared at this time as the data also forms part of an ongoing study.