Investigation on fluorescence and thermoluminescence of bismuth silicate crystal doped with Dy

Bismuth silicate single crystals doped with rare-earth dysprosium (Dy) were excited by ultra-violet laser pulses with pulse width of 100 ps and wavelength of 266 nm, the lifetime and spectra of the fluorescence were observed. After the samples were irradiated at liquid nitrogen temperature, the thermoluminescence was measured at the rate of 1 K/s. Fluorescence experiments show that the lifetime of the slow decay component is about 100 ns, and the fast decay component is weak; The incorporation of a small amount of Dy can enhance the fluorescent intensity, and so do to the lifetime of slow decay component of the fluorescence; the fluorescence intensity and lifetime decrease while the doping concentration is too large. Low temperature thermoluminescence measurements show that there are thermoluminescence peaks near 176 K and 230 K, and the corresponding energies of thermoluminescence traps are 0.27 eV and 0.36 eV. The presence of these shallow traps may attenuate the fast decay components of the crystal's fluorescence.