VUV excited luminescence and thermoluminescence investigation on Er3+- or Pr3+-doped BaY2F8 single crystals

Abstract Photoluminescence (PL), thermoluminescence (TL) emission spectra and TL glow curves of barium yttrium fluoride (BaY 2 F 8 – BaYF), undoped and doped with erbium (Er 3+ ) or praseodymium (Pr 3+ ) were measured to investigate the fundamental absorption (band gap – E g ), the nature of the trapping centers, as well as the electronic transitions of Ln 3+ in BaYF host. The band gap energy E g of BaY 2 F 8 was determined by vacuum ultraviolet (VUV) excitation measurements to be around 11.2 eV. Additionally, the electronic transition from excited states of Ln 3+ ions and the exciton state were also identified. TL emission spectra showed that the TL emission of doped samples is related to the Ln 3+ ion, indicating that the related host trapping centers are not affected by the new trapping centers originated due the dopant ions. Trap depths were calculated by fitting the glow curves using a first order kinetics model. Host-related trapping centers were attributed to intrinsic defects such as V k and F centers and the new TL peaks observed for Er and Pr-doped samples was associated to the electrons trapping centers. These results lead us to propose a simple model to explain the origin of the TL emission in BaYF.