Annealing effects on Czochralski grown Lu2Si2O7:Ce3+ crystals under different atmospheres

Cerium-doped lutetium pyrosilicate Lu2Si2O7:Ce3+ (LPS:Ce) single crystal samples grown via Czochralski method were annealed under air and H-2 atmospheres from 350 to 1600 degrees C. The x-ray excited luminescence spectra and UV as well as thermal stimulated luminescence spectra were measured. It was found that the luminescence efficiency after annealing in air at 1400 degrees C was significantly enhanced compared to the unannealed samples. This phenomenon was suggested to be caused by the existence of some oxygen vacancies in the LPS:Ce crystals, and these oxygen vacancies can be effectively eliminated by means of annealing in air. Although the annealing will lead to the oxidization of cerium ions from Ce3+ ions to Ce4+, which is harmful to the luminescent efficiency, the annealing treatment does enhance the luminescent efficiency of LPS:Ce, without changing its luminescence mechanics. (C) 2008 American Institute of Physics.