1. Study on the optical properties of CdWO4 crystal with oxygen vacancies
- Author
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Gaiping Lian, Tingyu Liu, and Le Yu
- Subjects
Nuclear and High Energy Physics ,Materials science ,Band gap ,Analytical chemistry ,chemistry.chemical_element ,Oxygen ,Crystal ,chemistry.chemical_compound ,chemistry ,Cadmium tungstate ,Density functional theory ,Absorption (electromagnetic radiation) ,Luminescence ,Luminous efficacy ,Instrumentation - Abstract
Cadmium tungstate crystals have attracted much attention because of its excellent scintillation performance. The existence of oxygen vacancies will reduce the luminous efficiency of the crystal, extend its luminous decay time and reduce light resolution of the crystal. However, the luminescence mechanism of the oxygen vacancies is not clear yet. Here, the optical properties of cadmium tungstate crystal with oxygen vacancies have been studied based on the Density Functional Theory (DFT). We calculated the defect formation energies of oxygen vacancies with three different charges (0, +1, +2), and corrected the band gap to make it more accurate. We obtained the absorption and emission peaks of the F center and F+ center for two different types of oxygen vacancies. The calculated absorption peaks of the F center of V OI and F+ center of V OII at 3.04 eV and 3.59 eV respectively, which are close to the experimental results (3.1 eV (400 nm) and 3.5 eV (350 nm)). So we speculate that these two obvious absorption peaks are caused by oxygen vacancies.
- Published
- 2021
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