TY - JOUR
T1 - Annealing-induced phase transformation in vapor deposited tellurium dioxide thin films and its structural, chemical analysis
AU - Chandra, K.
AU - Mahesha, M. G.
AU - Shetty, Pramoda Kumara
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2025/1/15
Y1 - 2025/1/15
N2 - Tellurium dioxide (TeO2) thin films were synthesized by thermal vacuum deposition on glass substrate and samples were annealed from 250 °C to 400 °C at 50 °C interval. The annealing was found to have a significant impact on the structural, optical, and electrical properties of TeO2 thin films. X-ray diffraction spectra (XRD) revealed an increase in crystallite size and corresponding decrease in micro strain and dislocation density with increasing temperature. Annealed sample at 350 °C and 400 °C showed phase change from γ-TeO2 to β-TeO2 since β phase is thermodynamically favourable with greater free energy change. X-ray Photoelectron spectroscopy of all annealed sample confirm the improvement in formation of TeO2 from metallic Tellurium with air annealing. The XPS analysis also confirmed the existence of interstitial Oxygen, and its concentration increased at 400 °C. Raman spectroscopy employed to investigate the variation in vibrational modes with temperature and correlate these findings with other structural and chemical analyses. Photoluminescence study of TeO2 thin films reveals evolution of defect states with annealing temperature. Decrease in intensity of defect-related emissions (green, near-IR) suggests improved crystallinity which was in turn supported by the disappearance of low-level defect peaks upon annealing.
AB - Tellurium dioxide (TeO2) thin films were synthesized by thermal vacuum deposition on glass substrate and samples were annealed from 250 °C to 400 °C at 50 °C interval. The annealing was found to have a significant impact on the structural, optical, and electrical properties of TeO2 thin films. X-ray diffraction spectra (XRD) revealed an increase in crystallite size and corresponding decrease in micro strain and dislocation density with increasing temperature. Annealed sample at 350 °C and 400 °C showed phase change from γ-TeO2 to β-TeO2 since β phase is thermodynamically favourable with greater free energy change. X-ray Photoelectron spectroscopy of all annealed sample confirm the improvement in formation of TeO2 from metallic Tellurium with air annealing. The XPS analysis also confirmed the existence of interstitial Oxygen, and its concentration increased at 400 °C. Raman spectroscopy employed to investigate the variation in vibrational modes with temperature and correlate these findings with other structural and chemical analyses. Photoluminescence study of TeO2 thin films reveals evolution of defect states with annealing temperature. Decrease in intensity of defect-related emissions (green, near-IR) suggests improved crystallinity which was in turn supported by the disappearance of low-level defect peaks upon annealing.
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U2 - 10.1016/j.matchemphys.2024.130160
DO - 10.1016/j.matchemphys.2024.130160
M3 - Article
AN - SCOPUS:85209108866
SN - 0254-0584
VL - 330
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
M1 - 130160
ER -