Influence of annealing atmosphere on the structural phase changes and optical properties of TiO₂ nanoparticles

¹ Department of Physics, Fatima Mata National College (Autonomous), Kollam, Kerala, India - 691001
² M. Dasan Institute of Technology, Ulliyeri PO, Kozhikode, Kerala, India - 673323

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Published online: 5 March 2026

Abstract

In the present work, structural and optical behaviour of sol-gel synthesized TiO₂ and Nitrogen doped TiO₂ (N-doped TiO₂) nanoparticles calcined under air and vacuum atmosphere have been analysed. N-doped TiO₂ samples were synthesized by adding ammonia as nitrogen source and as reducing agent. The molar concentration of Ammonia was fixed at 1 M and 2 M respectively. The incorporation of nitrogen into the TiO₂ samples was verified using X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) was used to examine the structural characteristics of air and vacuum-annealed samples, and Scherrer equation was used to determine the average crystallite size. Raman analysis was carried out to understand all the major modes of vibration in the annealed samples. UV-visible spectroscopy was carried to analyse the effect of different atmospheres on the band gap of the samples. Photoluminescence studies were used to understand the presence of defect states in the sample.