Structural and Optical Properties of ZnWO4:Er3+ Crystals

Erbium ion-(Er3+-) doped ZnWO4 crystals were synthesized via a hydrothermal method with different erbium concentrations. The prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman, UV-Vis, and photoluminescence (PL) spectroscopy. For ZnWO4:Er3+ crystals, a pure phase of ZnWO4 was obtained without any evidence of impurity present. The SEM images show that the grain size and morphology of ZnWO4:Er3+ material depends on the Er3+-dopant concentration. The UV-Vis spectra of ZnWO4:Er3+ compounds exhibited an absorption band at about 323 nm (3.83 eV) stemming from the [WO4](2-). Other absorption bands centered at 367, 379, 408, 490, and 522 nm are related to Er3+-ion transitions. Room temperature PL spectra of the ZnWO4:Er3+ compounds exhibited visible emission at 515-540 and 545-565 nm corresponding to the H-2(11/2)-I-4(15/2) and S-4(3/2)-I-4(15/2) transitions of Er3+ ions, respectively.