Luminescence and dosimetric characteristics of nanocrystalline Al2O3:C synthesized by thermal plasma reactor

Abstract

Nanocrystalline Al2O3:C has been synthesized by thermal plasma method. The sample was annealed at 1300 °C in air and vacuum. XRD studies show phase change from γ-Al2O3:C to α-Al2O3:C. Average particle sizes estimated from XRD peaks and TEM images show increase in the particle size from ~30 nm to ~ 67 nm. The UV–visible spectrum of the as-synthesized Al2O3:C shows absorption peaks at 209 and 255 nm confirming the formation of F and F+ centers. XPS analysis reveals that the concentration of carbon impurity remains intact in Al2O3 lattice. The TL glow curves were fitted by CGCD method. The glow curve of as-synthesized Al2O3:C found to have six peaks and that of annealed sample have four peaks. The changes in the glow curve structures of the as-synthesized and annealed phosphor may be attributed to the phase change of the crystal structure and/or different kinds of defects formed on annealing in air/vacuum.